Classification
Selective serotonin reuptake inhibitors (SSRIs) — e.g., Fluoxetine, Sertraline.
Serotonin-noradrenaline reuptake inhibitors (SNRIs) — e.g., Venlafaxine, Duloxetine.
Tricyclic antidepressants (TCAs) — e.g., Amitriptyline, Nortriptyline.
Monoamine oxidase inhibitors (MAOIs) — now less commonly used.
Atypical antidepressants — e.g., Mirtazapine, Bupropion.
Mechanism of Action (Pharmacodynamics)
SSRIs: inhibit serotonin reuptake at the presynaptic neuron, thereby increasing serotonin concentration in synaptic cleft.
SNRIs: inhibit reuptake of both serotonin and norepinephrine.
TCAs: inhibit reuptake of norepinephrine and serotonin, also block other receptors (e.g., muscarinic, histaminergic) → more side-effects.
MAOIs: inhibit monoamine oxidase (A or B) which breaks down monoamines (serotonin, norepinephrine, dopamine).
Atypicals: varied mechanisms (for Mirtazapine: antagonism of central α2 autoreceptors, enhancing noradrenergic/serotonergic transmission).
Pharmacokinetics
Varies by drug: absorption oral, metabolised in liver (CYP enzymes), varied half-lives, many have active metabolites; some require dose‐adjustment in hepatic/renal impairment.
Important: time-lag of clinical effect (often 4–6 weeks) despite faster pharmacologic action.
Indications
Major depressive disorder (MDD) – primary.
Anxiety disorders (e.g., GAD, panic disorder, social anxiety) — many antidepressants also used.
Other: OCD, PTSD, neuropathic pain (some), fibromyalgia (some SNRIs).
Side‐effects / Key Practical Considerations
SSRIs/SNRIs: nausea, headache, insomnia or somnolence, sexual dysfunction, weight changes, possible increased suicidal thoughts in younger people.
TCAs: anticholinergic (dry mouth, blurred vision, urinary retention), orthostatic hypotension, cardiac conduction issues; more toxic in overdose.
MAOIs: dietary restrictions (tyramine) due to hypertensive crisis risk, many drug interactions.
Withdrawal/ discontinuation syndrome: especially SNRIs/SSRIs (e.g., dizziness, flu-like symptoms) when stopped abruptly.
Onset is slow: improvements often seen after weeks; counsel patients accordingly.
Must monitor for drug–drug interactions, especially in polypharmacy (important in cardiometabolic patients).
Clinical/Pedagogic Notes
For medical students: emphasise that selection of antidepressant is often based on side‐effect profile, co-morbid conditions (e.g., anxiety + depression), drug interactions, patient preference.
For your PhD interest (cardiometabolic health): note interactions with cardiovascular drugs, impact on weight/ metabolism (some antidepressants cause weight gain which may be relevant in cardiometabolic context).
In anxiety: SSRIs/SNRIs are first line; benzodiazepines (see below) often adjunctive/short‐term.
Classification
Benzodiazepines — e.g., Diazepam, Lorazepam.
Non‐benzodiazepine anxiolytics — e.g., Buspirone.
Antidepressants (used for anxiety) — i.e., SSRIs/SNRIs used for anxiety disorders.
Other adjuncts: antihistamines (e.g., hydroxyzine), beta-blockers (for performance anxiety) etc.
Mechanism of Action
Benzodiazepines: enhance the effect of GABA at the GABAA_AA receptor, increasing inhibitory neurotransmission → sedation, anxiolysis, muscle relaxation.
Buspirone: partial agonist at 5-HT1A_{1A}1A receptors (serotonin), also some dopaminergic/adrenergic activity; slower onset, less risk of dependence.
SSRIs/SNRIs (for anxiety): by increasing serotonergic (and sometimes noradrenergic) neurotransmission, reducing anxiety via modulation of mood circuits.
Indications
Generalised anxiety disorder (GAD), panic disorder, social anxiety disorder, specific phobias (adjunct), insomnia (some), muscle spasms (for benzos).
Benzodiazepines also used in acute anxiety, acute agitation, status epilepticus (not purely anxiolytic role).
Side‐effects / Practical Considerations
Benzodiazepines: drowsiness, sedation, cognitive impairment, risk of dependence/ withdrawal, respiratory depression (especially with other depressants).
Buspirone: less sedation/ dependence; slower onset (weeks rather than immediate).
SSRIs/SNRIs for anxiety: same side effect profile as for depression; need time to act; switching/ dose-titration needed.
Key teaching point: Avoid long-term benzo use if possible; monitor for misuse; assess underlying causes of anxiety etc.
Clinical/Pedagogic Notes
For teaching: show difference between immediate relief (benzo) vs longer term management (SSRI) in anxiety disorders.
Emphasise in your cardiometabolic PhD context: anxiolytics and antidepressants have cardiovascular implications (e.g., metabolic side effects, drug interactions).
In patients with comorbid depression + anxiety + cardiometabolic disease (like metabolic syndrome), drug selection must consider all domains.
This section covers non-opioid analgesics, opioid analgesics, non-steroidal anti-inflammatory drugs (NSAIDs) and steroids as anti-inflammatory agents.
Definition / Classification
Non-opioid analgesics include drugs such as Acetaminophen (paracetamol) and the NSAIDs.
Antipyretic effect is the fever-reducing property (seen in NSAIDs and acetaminophen) as well.
Mechanism of Action
Acetaminophen: exact mechanism not fully clear; central action to reduce prostaglandin synthesis, antipyretic and analgesic but minimal anti-inflammatory.
NSAIDs: inhibit cyclooxygenase (COX) enzymes (COX-1 and/or COX-2) → decreased formation of prostaglandins, thromboxanes, prostacyclins.
Indications
Mild to moderate pain (headaches, musculoskeletal pain, dysmenorrhea) and fever.
Some non-opioid analgesics are used as adjuncts in chronic pain.
Key Side‐effects / Practical Considerations
Acetaminophen: well tolerated at therapeutic doses, but overdose → hepatotoxicity.
NSAIDs: gastrointestinal (GI) irritation/ulcers, renal impairment (especially in volume‐depleted states), increased cardiovascular risk (esp. certain selective COX-2 inhibitors), bleeding risk (platelet inhibition with aspirin etc).
Teaching point: For NSAIDs, must consider patient’s GI risk, renal function, cardiovascular status (very relevant in cardiometabolic health).
Ceiling effect (for many NSAIDs): above certain dose no further analgesia but increased risk of side-effects.
Classification
Opioids (“narcotics”) include agents such as Morphine, Fentanyl, Oxycodone, etc. (For detailed list one would refer to specific textbooks).
These are used for moderate-to-severe pain.
Mechanism of Action
Bind to opioid receptors (mu, delta, kappa) in CNS and peripheral tissues → inhibit pain transmission, increase pain threshold, alter pain perception/emotional response.
Indications
Severe acute pain (post-operative, trauma, cancer pain), chronic pain (carefully selected), palliative care.
Sedation, respiratory depression, constipation (common), nausea/vomiting, itching, tolerance, dependence/abuse potential.
Because of safety concerns (especially in chronic non-malignant pain) and the opioid epidemic, need careful monitoring, dose-limiting, combinations etc.
Teaching point: In analgesic-plans, balancing non-opioid + opioid, consider step-wise escalation, contraindications, patient risk factors (especially in cardiometabolic disease where respiratory depression + sedation may affect comorbidities).
We have already partly covered under non-opioid analgesics; here’s a more focused look.
Mechanism of Action
As above: Block COX enzymes → less prostaglandin/thromboxane production → less pain, inflammation, fever.
Indications
Pain with inflammatory component (arthritis, musculoskeletal injuries, dysmenorrhea, gout flare, renal colic etc). Fever, mild pain conditions, prophylaxis of certain cardiovascular events (in aspirin’s case).
Side‐effects / Risks
GI: dyspepsia, ulceration, bleeding.
Renal: decreased renal perfusion (via prostaglandin blockade) especially in hypovolemia or CKD.
Cardiovascular: Some NSAIDs increase risk of myocardial infarction, stroke (especially COX-2 selective).
Drug interactions: e.g., with anticoagulants (bleeding risk), antihypertensives (renal perfusion effects) etc.
Clinical Notes
Among analgesics, NSAIDs may provide analgesia comparable to opioids in some acute settings.
Important to assess individual patient risk (age, renal/hepatic function, cardiovascular status, concomitant medications).
For your cardiometabolic health interest: NSAIDs may impact hypertension, renal function, fluid retention — all relevant in patients with metabolic syndrome, CKD etc.
Teaching point: Distinguish analgesic vs anti-inflammatory vs antipyretic effects (NSAIDs cover all three), recognise ceiling dose, emphasise that selective COX-2 inhibitors may reduce GI risk but increase cardiovascular risk.
Classification
Systemic corticosteroids: e.g., Prednisone, Dexamethasone
Local (intra-articular, topical) corticosteroids for inflammation
Mechanism of Action (Pharmacodynamics)
Mimic endogenous glucocorticoids: bind to intracellular glucocorticoid receptors → modulate gene transcription → reduce production of pro-inflammatory cytokines, inhibit phospholipase A2 (thus less arachidonic acid → less prostaglandins/leukotrienes), reduce capillary permeability, inhibit immune cell migration.
They have strong anti-inflammatory and immunosuppressive effects.
Indications
Moderate-to-severe inflammatory and autoimmune conditions (e.g., rheumatoid arthritis, lupus, asthma exacerbations, COPD exacerbations, severe allergic reactions)
As adjunct in certain infectious/inflammatory states, in organ transplantation, adrenal insufficiency etc.
In pain/inflammation when NSAIDs insufficient or contraindicated.
Side‐effects / Practical Considerations
Short-term: hyperglycaemia, fluid retention, hypertension, mood changes, increased appetite
Long-term: osteoporosis, adrenal suppression, immunosuppression (infection risk), glaucoma/cataracts, skin thinning, fat redistribution, metabolic syndrome (weight gain, dyslipidaemia)
In cardiometabolic context: steroids can worsen hypertension, hyperglycaemia, dyslipidaemia — highly relevant for your PhD interest.
Use lowest effective dose, shortest duration possible; monitor for complications.
When using with NSAIDs, combined risk of GI bleeding may be higher.
Clinical Notes
In inflammatory pain conditions (e.g., rheumatoid arthritis) steroids may be used when NSAIDs insufficient — systematic reviews exist but long-term safety data are limited.
Teaching point: Distinguish between anti-inflammatory agents (NSAIDs, steroids) vs pure analgesics (some non-opioids) vs analgesics with anti-inflammatory effect.
Emphasise tapering of steroids when used > 2-3 weeks to avoid adrenal insufficiency.
In cardiometabolic patients (obesity, diabetes, hypertension) caution with steroids given metabolic side‐effects.
Analgesia vs Anti-inflammation: Some drugs relieve pain by reducing inflammation (NSAIDs, steroids), some relieve pain by central modulation (opioids, antidepressants used for pain) and some reduce pain by lowering the fever or general nociception (acetaminophen).
Step-wise approach in pain: Mild pain → non‐opioid analgesics (acetaminophen/NSAIDs) → moderate pain → add opioids or stronger non-opioid + adjuvants → severe pain → opioids (with caution).
Adjuvant analgesics: Some antidepressants (especially TCAs, SNRIs) and anticonvulsants are used for neuropathic pain (though this lies outside your list but good to mention).
Chronic vs acute use: Analgesics/NSAIDs are often used acutely; steroids and some chronic anti-inflammatory treatments may be long-term but require monitoring.
Comorbidities matter: In patients with cardiometabolic disease (hypertension, diabetes, CKD) selecting analgesics/anti-inflammatories needs extra care (renal risk, fluid retention, blood‐pressure effects, cardiovascular risk).
Drug interactions: Antidepressants with anxiolytics may interact; NSAIDs with anticoagulants/antiplatelets; steroids with many metabolic drugs; opioids with central depressants.
Teaching methodology: For your audience (medical students/PhD), structure each class or presentation by: classification → mechanism → kinetics (brief) → indications → contraindications/side effects → special populations (cardiometabolic, renal, hepatic) → clinical cases/quiz.
Clinical case inclusion: It’s beneficial to include case studies: e.g., patient with CKD on NSAIDs for osteoarthritis and develops AKI; or patient with depression + T2DM on SSRI and weight gain; or patient with RA on steroids who develops hypertension + hyperglycaemia.
The central nervous system (CNS) serves as the integrative command center of the human body, coordinating sensory input, motor output, and higher cognitive functions. Pharmacological modulation of the CNS forms the basis for managing a broad spectrum of neurological and psychiatric disorders. This chapter provides an in-depth exploration of the mechanisms, classifications, pharmacokinetics, and clinical applications of CNS stimulants, hypnotics, sedatives, tranquilizers, and anticonvulsant agents—drawing upon recent neuroscientific and pharmacogenomic research.
CNS stimulants are psychotropic substances that increase neuronal firing rates, elevate mood, and enhance alertness. Their effects primarily arise through monoaminergic activation, involving dopamine (DA), norepinephrine (NE), and serotonin (5-HT) neurotransmission.
Amphetamines: Promote presynaptic release and inhibit reuptake of DA and NE.
Methylphenidate: Selective DAT/NET reuptake blockade, enhancing cortical catecholamine levels.
Caffeine and theophylline: Antagonize adenosine A1/A2A receptors, disinhibiting excitatory transmission.
Modafinil: Stimulates orexin and histaminergic neurons, supporting wakefulness.
Amphetamines: t½ ≈ 10 h, extensive hepatic metabolism (CYP2D6).
Modafinil: t½ ≈ 15 h, hepatic conjugation.
Caffeine: t½ ≈ 5 h, metabolized by CYP1A2.
Attention-Deficit/Hyperactivity Disorder (ADHD)
Narcolepsy and excessive daytime sleepiness
Apnea of prematurity (caffeine citrate)
Insomnia, anxiety, tachycardia, hypertension, tolerance, dependence, and potential psychosis with chronic abuse.
Sedatives calm and reduce anxiety without inducing sleep.
Hypnotics induce and maintain sleep.
Both act predominantly via GABA-A receptor potentiation, enhancing inhibitory neurotransmission.
| Drug Class | Mechanism | Key Features |
|---|---|---|
| Benzodiazepines | Increase Cl⁻ channel opening frequency at GABA-A receptor | Anxiolytic, anticonvulsant, muscle relaxant |
| Barbiturates | Prolong Cl⁻ channel opening duration | High overdose risk |
| Z-drugs (zolpidem, zaleplon) | Selective α1-subunit activation | Minimal hangover effect |
| Melatonin agonists | Act on MT1/MT2 receptors | Circadian regulation |
Rapid GI absorption, high lipid solubility, hepatic metabolism via CYP3A4, and urinary excretion of glucuronide conjugates.
Insomnia management
Pre-anesthetic sedation
Status epilepticus (diazepam, lorazepam)
Muscle spasm control
Drowsiness, amnesia, tolerance, dependence, and respiratory depression (especially barbiturates).
Tranquilizers attenuate pathological anxiety through limbic GABAergic and serotonergic modulation. They recalibrate amygdalo-prefrontal circuitry to normalize stress response.
Benzodiazepines: Diazepam, Alprazolam, Lorazepam.
Azapirones: Buspirone (5-HT1A partial agonist, non-sedating).
SSRIs/SNRIs: Sertraline, Venlafaxine—long-term anxiety control.
β-blockers: Propranolol—for somatic anxiety symptoms.
CYP2C19 polymorphisms alter SSRI metabolism.
5-HTTLPR gene variants influence therapeutic response and tolerance.
Dependence, psychomotor impairment, withdrawal symptoms, and tolerance development in chronic benzodiazepine users.
Epilepsy arises from hypersynchronous neuronal discharges caused by excitatory-inhibitory imbalance. Antiepileptic drugs (AEDs) stabilize membranes, suppress repetitive firing, and enhance inhibitory signaling.
| Mechanism | Representative Agents | Molecular Target |
|---|---|---|
| Na⁺-channel blockade | Phenytoin, Carbamazepine, Lamotrigine | Voltage-gated Na⁺ channels |
| Ca²⁺-channel blockade | Ethosuximide | Thalamic T-type Ca²⁺ channels |
| GABA enhancement | Valproate, Phenobarbital, Benzodiazepines | GABA-A receptors |
| Glutamate inhibition | Topiramate, Felbamate | NMDA/AMPA receptors |
| Synaptic vesicle modulation | Levetiracetam | SV2A protein |
Phenytoin: Non-linear kinetics, zero-order metabolism.
Carbamazepine: CYP3A4 inducer; autoinduction phenomenon.
Valproate: Broad-spectrum; inhibits CYP2C9.
Generalized and partial seizures
Absence seizures (ethosuximide)
Status epilepticus (benzodiazepines)
Neuropathic pain (carbamazepine, gabapentin)
CNS depression, ataxia, diplopia
Hepatotoxicity (valproate)
Gingival hyperplasia (phenytoin)
Stevens–Johnson syndrome (carbamazepine, lamotrigine)
Teratogenicity—especially neural tube defects with valproate
HLA-B*15:02: Carbamazepine hypersensitivity in Asians.
CYP2C9 variants: Alter phenytoin clearance and toxicity profile.
| Class | Principal Neurotransmitter System | Target Receptor | Clinical Outcome | Major Limitation |
|---|---|---|---|---|
| CNS Stimulants | DA/NE ↑ | DAT/NET | Wakefulness, focus | Addiction, insomnia |
| Hypnotics | GABA ↑ | GABA-A α1 | Sleep induction | Respiratory depression |
| Sedatives | GABA ↑ | GABA-A α2 | Calming, anxiolysis | Tolerance |
| Tranquilizers | 5-HT/GABA ↑ | 5-HT1A, GABA-A | Anxiolysis | Dependence |
| Antiepileptics | GABA ↑ / Glutamate ↓ | Na⁺, Ca²⁺, NMDA | Seizure suppression | Hepatotoxicity, rash |
Combination therapy: Mechanism-based rational polytherapy enhances seizure control and minimizes toxicity.
Neuroinflammation targeting: IL-1β and TNF-α inhibitors show promise as adjuncts in drug-resistant epilepsy.
Precision medicine: Integration of EEG phenotyping, genomics, and AI algorithms for individualized dosing.
Epigenetic approaches: Valproate and new HDAC inhibitors under investigation for neuroplastic modulation.
CNS pharmacotherapy remains a cornerstone of modern neuroscience. A profound understanding of molecular mechanisms, receptor subtypes, and pharmacogenomic variability is essential for optimizing clinical outcomes. Future research lies in personalized neuropharmacology, leveraging AI-driven modeling and genomic profiling to refine therapeutic precision and minimize adverse effects.
Brunton, L. L., Hilal-Dandan, R., & Knollmann, B. C. (Eds.). (2023). Goodman & Gilman’s: The Pharmacological Basis of Therapeutics (14th ed.). McGraw-Hill Education.
Katzung, B. G., Vanderah, T. W., & Trevor, A. J. (2021). Basic and Clinical Pharmacology (15th ed.). McGraw-Hill Education.
Rang, H. P., Ritter, J. M., Flower, R. J., & Henderson, G. (2019). Rang & Dale’s Pharmacology (9th ed.). Elsevier.
Perucca, E., & Tomson, T. (2020). The pharmacological treatment of epilepsy. Epilepsia, 61(S2), S2–S12.
Stahl, S. M. (2021). Stahl’s Essential Psychopharmacology: Neuroscientific Basis and Practical Applications (5th ed.). Cambridge University Press.
Meyer, J. S., & Quenzer, L. F. (2018). Psychopharmacology: Drugs, the Brain, and Behavior (3rd ed.). Oxford University Press.
The ANS is the part of the peripheral nervous system that controls involuntary (automatic) physiological processes (such as heart rate, vascular tone, digestion, pupil size, respiratory rate) via efferent motor fibres.
It works by balancing two major functional divisions:
The Sympathetic nervous system (SNS) — “fight or flight” responses.
The Parasympathetic nervous system (PNS) — “rest and digest” responses.
The ANS uses specific receptors: adrenergic (α, β) for the SNS, and muscarinic & nicotinic for the PNS.
From a pharmacological perspective, many drugs act by mimicking or blocking these autonomic pathways (so-called autonomic agents).
Because virtually all organ systems (cardiovascular, respiratory, gastrointestinal, urinary, ocular) are influenced by autonomic tone, drugs working on the ANS are clinically very important (e.g., in hypertension, asthma, glaucoma, shock).
Understanding the ANS anatomy and receptor pharmacology helps predict both therapeutic effects and side-effects of many drug classes. Medicine LibreTexts+1
According to major standard texts:
Cholinomimetics (parasympathomimetics)
Anticholinergics (parasympatholytics)
Adrenoreceptor agonists (sympathomimetics)
Adrenoreceptor antagonists (sympatholytics)
These categories often serve as the backbone for detailed drug classification.
Here is a refined breakdown (relevant for your level) of the major classes of autonomic-acting drugs, focusing on the adrenergic side (since we’ll then focus on sympathomimetics & sympatholytics):
| Major class | Direction of effect | Primary receptors / mechanism |
|---|---|---|
| Sympathomimetics (adrenergic agonists) | Enhance SNS activity | α- and/or β-adrenergic receptor agonism; direct or indirect catecholamine release. UH Pressbooks+1 |
| Sympatholytics (adrenergic antagonists) | Inhibit SNS activity | Blockade or suppression of adrenergic (α, β) receptors OR inhibition of catecholamine release/storage. AMBOSS |
| Parasympathomimetics (cholinergic agonists) | Enhance PNS activity | Muscarinic / nicotinic receptor agonists |
| Parasympatholytics (cholinergic antagonists) | Inhibit PNS activity | Muscarinic receptor antagonists |
Because you asked specifically for sympathomimetic and sympatholytic agents, the remainder of this note will concentrate on those.
Sympathomimetic drugs are those that mimic or enhance the actions of the sympathetic nervous system (i.e., they mimic endogenous catecholamines like norepinephrine and epinephrine).
Mechanistically, they may act:
Direct-acting: bind and activate adrenergic receptors (α or β).
Indirect-acting: increase release or block re-uptake of endogenous catecholamines.
Mixed-acting: both mechanisms in one drug.
Multiple approaches exist; one practical scheme for students:
A. By receptor selectivity
α₁-agonists (→ vasoconstriction, mydriasis)
α₂-agonists (presynaptic inhibition of NE release in some cases)
β₁-agonists (→ increases heart rate & contractility)
β₂-agonists (→ bronchodilation, vasodilation in skeletal muscle)
Dopaminergic (D₁/D₂) agonists (in some cases)
B. By mechanism of action
Direct acting
Indirect acting
Mixed acting
C. By therapeutic application (less important for classification but useful)
Bronchodilators (β₂ agonists)
Vasopressors / inotropes (α₁, β₁ agonists)
Decongestants (α₁ agonists)
CNS stimulants (some indirect sympathomimetics)
Activation of SNS — e.g., increased heart rate & contractile force (β₁), increased BP via vasoconstriction (α₁), bronchodilation (β₂)
Useful in: shock/hypotension, anaphylaxis (epinephrine), asthma/COPD (β₂ agonists), nasal congestion (α₁ agonist)
Note: because they activate the SNS, side-effects reflect “over-drive” (tachycardia, hypertension, arrhythmias, etc).
Phenylephrine (α₁-agonist decongestant/pressor)
Dobutamine (β₁-agonist inotropic agent)
Albuterol (β₂-agonist bronchodilator)
When you hear “adrenergic agonist → SNS activation → increased HR/BP/bronchodilation”, think sympathomimetic.
Knowing the receptor subtype helps: e.g., β₂ agonist → bronchodilation → asthma; α₁ agonist → vasoconstriction → raises BP or nasal decongestant.
Beware indirect acting agents — they may have broader effects and higher risk of side-effects (e.g., CNS stimulation).
In exam/clinical context: recall that if you give a sympathomimetic, you increase sympathetic tone; conversely blocking the SNS is the domain of sympatholytics (below).
Sympatholytic drugs are those that inhibit or block the sympathetic nervous system – also called anti-adrenergic agents.
Mechanisms involve:
Receptor antagonism: α-blockers, β-blockers (prevent NE/epinephrine action).
Inhibition of catecholamine synthesis/storage/release: e.g., drugs reducing NE release from nerve terminals.
Central sympathoinhibition: drugs acting on CNS to reduce sympathetic outflow (e.g., α₂-agonists acting presynaptically).
A useful classification for your level:
Peripheral adrenergic antagonists
α₁-blockers (reduce vasoconstriction)
α₂-blockers (rare clinically)
β₁- and β₂-blockers
Drugs interfering with catecholamine release/storage
e.g., Reserpine (depletes NE)
Centrally acting agents
α₂-agonists (paradox: act to reduce SNS output) such as Clonidine
Decrease SNS tone: lower heart rate (β₁), reduce BP (α₁ blockade reduces vasoconstriction), reduce cardiac output, etc.
Clinical uses include: hypertension, angina, arrhythmias, benign prostatic hyperplasia (via α₁-block), anxiety (some β-blockers)
Side-effects: bradycardia, hypotension, bronchospasm (β₂ blockade), orthostatic hypotension (α₁ blockade), fatigue.
Prazosin (α₁-blocker – used in hypertension, BPH)
Propranolol (non-selective β-blocker)
Atenolol (β₁-selective β-blocker)
If a drug is described as “adrenergic blocker” or “anti-adrenergic” in exam, it is a sympatholytic.
Remember reflex responses: e.g., if you block α₁ → vasodilation → you might get reflex tachycardia. That links to side-effects.
In clinical scenarios: if patient has hypertension + tachycardia, a β-blocker might help both; but if asthma present, beware β₂-blocker caution.
For BPH with hypertension: α₁-blocker (e.g., prazosin) useful because it relaxes prostate smooth muscle and reduces BP.
| Drug Class | Primary Action | Representative Receptors | Clinical Use | Key Side-Effects |
|---|---|---|---|---|
| Sympathomimetics | ↑ SNS tone | α, β agonism | Asthma, shock, decongestion | Hypertension, tachycardia, arrhythmia |
| Sympatholytics | ↓ SNS tone | α, β antagonism or NE release ↓ | Hypertension, angina, BPH | Bradycardia, hypotension, bronchospasm |
In cardiometabolic health, manipulation of the SNS is critical: e.g., β-blockers reduce cardiac workload and improve outcomes in heart failure; α₁-blockers may improve vascular tone.
Recognising that sympathomimetic drugs may worsen hypertension, arrhythmias, or ischemia is important in vulnerable patients.
In metabolic disease (e.g., diabetes, obesity), sympathetic overactivity (and parasympathetic underactivity) may play a role; thus sympatholytics may have beneficial roles beyond BP control (though this is complex).
Always correlate receptor pharmacology with clinical situation: what receptor does drug act on, what is the downstream organ/tissue effect, what are possible compensatory responses/reflexes?
Drugs Acting on the Pituitary
The pituitary gland (hypophysis) is the master endocrine organ controlling hormone secretion from target glands. Drugs acting on it are used for hormone replacement, suppression of excess hormone, or diagnostic purposes. These notes summarize the major drug classes, mechanisms, and Kenyan clinical details.
• Hypothalamic–pituitary axis regulators (e.g. GnRH analogues)
• Pituitary hormone replacements (GH, ACTH analogues)
• Hormone release inhibitors (Somatostatin analogues, Dopamine agonists)
• Posterior pituitary hormone analogues (Vasopressin, Oxytocin)
Mechanism: Stimulates IGF-1 synthesis → promotes growth of bones, cartilage, and soft tissue.
Indications: GH deficiency, Turner’s syndrome, chronic renal failure with growth retardation.
Dose: 0.025–0.035 mg/kg/day subcutaneously.
Kenyan Trade Names: Norditropin®, Genotropin®.
Adverse Effects: Edema, arthralgia, headache, increased intracranial pressure, hyperglycemia.
Clinical Notes: Monitor growth velocity and glucose tolerance regularly.
Mechanism: Blocks GH receptors → decreases IGF-1 levels.
Indication: Acromegaly refractory to surgery or somatostatin analogues.
Dose: 10–20 mg subcutaneously daily.
Trade Name: Somavert®.
Adverse Effects: Elevated liver enzymes, injection-site pain.
Clinical Notes: Monitor liver enzymes periodically.
Mechanism: Continuous stimulation → downregulation of GnRH receptors → suppression of LH/FSH.
Indications: Prostate cancer, endometriosis, uterine fibroids, precocious puberty.
Dose: Leuprolide 3.75 mg IM monthly; Goserelin 3.6 mg SC monthly.
Trade Names: Zoladex®, Lucrin Depot®.
Adverse Effects: Hot flashes, bone loss, decreased libido, mood swings.
Clinical Notes: Use add-back therapy (estrogen/progestin) to minimize bone loss.
Mechanism: Block GnRH receptors → immediate inhibition of LH/FSH release.
Indications: Endometriosis, ovarian hyperstimulation prevention, advanced prostate cancer.
Dose: Elagolix 150 mg orally daily.
Trade Names: Cetrotide®, Orilissa®, Firmagon®.
Adverse Effects: Hot flashes, headache, bone density loss.
Mechanism: D2 receptor agonist → inhibits prolactin secretion.
Indications: Hyperprolactinemia, prolactinoma, galactorrhea, Parkinson’s adjunct.
Dose: 1.25–2.5 mg orally twice daily.
Trade Names: Parlodel®, Bromergon®.
Adverse Effects: Nausea, vomiting, orthostatic hypotension.
Clinical Notes: Start low and titrate to avoid hypotension.
Mechanism: Long-acting D2 agonist → suppresses prolactin secretion.
Indications: Hyperprolactinemia, prolactinoma.
Dose: 0.25–0.5 mg twice weekly.
Trade Name: Dostinex®.
Adverse Effects: Nausea, dizziness, fatigue.
Clinical Notes: Better tolerated and more effective than bromocriptine.
Mechanism: V2 receptor agonist in kidney → promotes water reabsorption.
Indications: Central diabetes insipidus, nocturnal enuresis, mild hemophilia A.
Dose: 10–20 µg intranasally or 0.2 mg orally daily.
Trade Names: Minirin®, DDAVP®.
Adverse Effects: Hyponatremia, headache, nasal irritation.
Clinical Notes: Monitor serum sodium regularly.
Mechanism: Binds uterine oxytocin receptors → stimulates uterine contractions.
Indications: Labor induction, postpartum hemorrhage prevention.
Dose: 1–5 IU IV infusion titrated to uterine response.
Trade Names: Syntocinon®.
Adverse Effects: Uterine hyperstimulation, water intoxication (rare).
Clinical Notes: Use only under medical supervision in hospital settings.
|
Drug/Class |
Mechanism |
Indication |
Key Adverse Effects |
|
Somatropin |
Stimulates IGF-1 → growth |
GH deficiency |
Edema, hyperglycemia |
|
Leuprolide |
Downregulates GnRH receptors |
Prostate CA, Endometriosis |
Hot flashes, osteoporosis |
|
Cabergoline |
D2 agonist → ↓ prolactin |
Prolactinoma |
Nausea, fatigue |
|
Desmopressin |
V2 agonist → water reabsorption |
Diabetes insipidus |
Hyponatremia |
|
Oxytocin |
Uterine contraction |
Labor induction |
Uterine hypertonus |
• Bromocriptine and cabergoline are available in Kenyan pharmacies.
• GH therapy (Somatropin) is specialist-prescribed and expensive.
• Desmopressin widely used for nocturnal enuresis and diabetes insipidus.
• Oxytocin (Syntocinon®) is standard in Kenyan maternity units.
• Monitor side effects: blood pressure, sodium, liver enzymes, bone density.
Hormonal Contraceptives
Hormonal contraceptives are drugs that use synthetic estrogen and/or progestin to prevent pregnancy. They act by suppressing ovulation, altering cervical mucus, and changing the endometrial lining. In Kenya, these agents are available in oral, injectable, implant, and intrauterine forms.
• Combined oral contraceptives (COCs): Estrogen + Progestin
• Progestin-only pills (POPs) – Mini-pills
• Injectable contraceptives – Depo-Provera®, Noristerat®
• Implants – Jadelle®, Implanon®
• Intrauterine systems (IUS) – Mirena®
• Emergency contraceptive pills – Postinor-2®, Levonelle®
• Suppress ovulation: Estrogen and progestin inhibit GnRH release → ↓ LH and FSH → no ovulation.
• Cervical mucus thickening: Progestin makes mucus hostile to sperm.
• Endometrial changes: Prevent implantation.
• Tubal motility changes: Reduce sperm/egg transport.
Composition: Ethinylestradiol (20–35 µg) + Progestin (Levonorgestrel, Norethisterone, Drospirenone).
Suppress LH/FSH → inhibit ovulation and stabilize endometrium.
• Contraception
• Menstrual regulation
• Endometriosis and dysmenorrhea
• Acne and hirsutism (antiandrogenic progestins)
One tablet daily for 21 days, followed by 7-day pill-free interval or placebo pills.
Microgynon®, Marvelon®, Yaz®, Rigevidon®.
• Mild: Nausea, breast tenderness, headache, breakthrough bleeding.
• Serious: Venous thromboembolism (VTE), hypertension, migraine exacerbation.
• Long-term: Slightly increased risk of cervical cancer; reduced risk of ovarian and endometrial cancer.
• Smoking in women >35 years
• History of VTE, stroke, or ischemic heart disease
• Migraine with aura
• Breast cancer
• Uncontrolled hypertension
Composition: Levonorgestrel 30 µg or Desogestrel 75 µg per tablet.
Mechanism: Thickens cervical mucus, suppresses ovulation in 50–60% of cycles, and alters endometrium.
Dose: One tablet daily at the same time each day (strict adherence required).
Kenyan Brands: Microlut®, Noriday®, Cerazette®.
Adverse Effects: Irregular bleeding, amenorrhea, headache, breast tenderness.
Clinical Notes: Safe for breastfeeding women and those with estrogen contraindications.
• Depo-Provera® (Medroxyprogesterone acetate 150 mg IM every 12 weeks)
• Noristerat® (Norethisterone enanthate 200 mg IM every 8 weeks)
Mechanism: Suppresses ovulation, thickens cervical mucus, and thins endometrium.
Advantages: High efficacy, no daily pill.
Disadvantages: Delayed return to fertility (6–12 months), menstrual irregularities.
Adverse Effects: Weight gain, decreased bone mineral density (long-term use), mood changes.
Clinical Notes: Used widely in Kenyan family planning clinics; calcium supplementation recommended for long-term users.
• Jadelle® (Levonorgestrel) – effective 5 years.
• Implanon® (Etonogestrel) – effective 3 years.
Mechanism: Continuous progestin release suppresses ovulation and thickens cervical mucus.
Adverse Effects: Irregular bleeding, headache, acne, mood swings.
Clinical Notes: Effective, long-term, reversible. Insertion and removal require trained personnel.
• Mirena® – releases levonorgestrel 20 µg/day for 5 years.
Mechanism: Local progestin effect → inhibits endometrial proliferation and thickens cervical mucus.
Advantages: Long-acting, low systemic hormone exposure, reduces menorrhagia.
Adverse Effects: Irregular bleeding initially, pelvic discomfort.
Clinical Notes: Inserted by trained providers; available in major Kenyan referral hospitals.
• Levonorgestrel 1.5 mg single dose (Postinor-2®, NorLevo®)
• Ulipristal acetate 30 mg (EllaOne® – less common in Kenya)
Mechanism: Delays ovulation and prevents fertilization (does not terminate pregnancy).
Administration: Take within 72 hours of unprotected intercourse (earlier = more effective).
Adverse Effects: Nausea, vomiting, menstrual delay.
Clinical Notes: Widely available in Kenyan pharmacies and clinics.
• Reduced dysmenorrhea and menstrual blood loss.
• Protection against ovarian and endometrial cancers.
• Improvement of acne and hirsutism.
• Management of polycystic ovarian syndrome (PCOS).
|
Method |
Duration |
Main Mechanism |
Common Side Effects |
|
COCs |
Daily |
Inhibit ovulation |
Nausea, headache, VTE |
|
POPs |
Daily |
Thicken cervical mucus |
Irregular bleeding |
|
Depo-Provera |
3 months |
Suppress ovulation |
Weight gain, amenorrhea |
|
Implanon/Jadelle |
3–5 years |
Continuous progestin release |
Spotting, headache |
|
Mirena IUS |
5 years |
Local endometrial effect |
Initial irregular bleeding |
• Family planning services are offered free in public hospitals under the Ministry of Health.
• Depo-Provera and Implants (Jadelle®, Implanon®) are the most commonly used hormonal methods.
• National guidelines emphasize counselling before initiation and management of side effects.
• HIV-positive women can safely use hormonal contraception; however, drug interactions with ART should be considered.
• Emergency contraception is available OTC but should not replace regular contraception.
The nervous system pharmacology is huge; for clarity we break it into:
The autonomic nervous system (ANS) part – which covers the sympathetic (adrenergic) and parasympathetic (cholinergic) divisions; drugs that mimic or block each side.
The central nervous system (CNS) part – which covers stimulants, sedatives/hypnotics/tranquillisers, antiepileptics, antidepressants/anxiolytics, analgesics/antipyretics/anti-inflammatories, rheumatology/gout, rigidity & tremor controllers (e.g., Parkinson’s), plus anaesthetics & muscle relaxants.
Understanding the ANS is foundational because many drugs either mimic or block the normal “fight-or-flight / rest-and-digest” balance.
The ANS regulates involuntary body functions (heart rate, digestion, bronchi, pupils, glands).
Divided into:
Sympathetic (adrenergic): “fight or flight” – ↑ heart rate, dilate bronchi, dilate pupils, divert blood to muscles.
Parasympathetic (cholinergic): “rest and digest” – ↓ heart rate, ↑ GI motility, constrict pupils, stimulate secretions.
Drugs can modify these by: stimulating (agonists) or blocking (antagonists) either branch.
Major classification groups:
Cholinomimetics (parasympathomimetics) – mimic acetylcholine at muscarinic/nicotinic receptors or inhibit acetylcholinesterase.
Anticholinergics (parasympatholytics) – block cholinergic receptors.
Sympathomimetics (adrenergic agonists) – stimulate alpha/beta adrenergic receptors.
Sympatholytics (adrenergic antagonists) – block the adrenergic receptors (alpha-blockers, beta-blockers, etc.)
Mechanism: Activate adrenergic receptors (α, β) in target organs → mimic sympathetic stimulation.
Main classes & examples
Non-selective: e.g., adrenaline (epinephrine) – acts on α & β.
α1 agonists: e.g., phenylephrine (vasoconstrictor).
β1 agonists: e.g., dobutamine (cardiac stimulant).
β2 agonists: e.g., salbutamol (bronchodilator) for asthma.
Indications: Anaphylaxis (adrenaline), asthma/bronchospasm, cardiogenic shock, nasal congestion.
Key side-effects: Tachycardia, hypertension, arrhythmias, tremor, anxiety.
Key point for diploma students: Recognise that these drugs increase sympathetic output and expect “fight or flight” effects.
Mechanism: Block adrenergic receptors → reduce sympathetic effects. pharmaguideline.com+1
Main classes & examples:
α-blockers: e.g., prazosin (reduce peripheral resistance).
β-blockers: e.g., propranolol (non-selective), metoprolol (β1 selective) – reduce heart rate, blood pressure.
Indications: Hypertension, angina, arrhythmias, benign prostatic hyperplasia (for α-blockers).
Side-effects: Bradycardia, hypotension, bronchospasm (with β2 block), impotence, fatigue.
Key point: They reduce “fight or flight” output – useful when sympathetic overactivity is harmful.
Mechanism: Stimulate muscarinic/nicotinic receptors or inhibit acetylcholinesterase → increase parasympathetic tone.
Examples:
Direct-acting muscarinic agonists: bethanechol (bladder/urinary retention), pilocarpine (glaucoma).
Indirect acting (acetylcholinesterase inhibitors): neostigmine (myasthenia gravis), physostigmine.
Indications: Urinary retention, glaucoma, myasthenia gravis.
Side-effects: Diarrhoea, bradycardia, bronchospasm, sweating, salivation.
Key point: They promote rest-and-digest responses.
Mechanism: Block muscarinic receptors → reduce parasympathetic tone.
Examples: Atropine (↑ heart rate, reduce GI motility, mydriasis), ipratropium (bronchodilator).
Indications: Bradycardia, pre-anaesthetic (to reduce secretions), overactive bladder, COPD/asthma (anticholinergic inhalers).
Side-effects: Dry mouth, blurred vision, constipation, urinary retention, tachycardia.
Key point: They dampen rest-and-digest responses, so expect opposite effects to parasympathomimetic agents.
| Drug‐class | Branch affected | Mechanism | Key clinical uses | Common side-effects |
|---|---|---|---|---|
| Sympathomimetics | Sympathetic ↑ | Agonist at α/β | Asthma (β2), anaphylaxis (α/β), shock | Tachycardia, HTN, tremor |
| Sympatholytics | Sympathetic ↓ | Block α/β | Hypertension, angina, arrhythmias | Bradycardia, hypotension |
| Parasympathomimetics | Parasympathetic ↑ | Stimulate muscarinic/nicotinic or inhibit AChE | Urinary retention, glaucoma, myasthenia gravis | Diarrhea, bronchospasm |
| Parasympatholytics | Parasympathetic ↓ | Block muscarinic receptors | Bradycardia, COPD/asthma (anticholinergic), pre-operative | Dry mouth, tachycardia, urinary retention |
Always consider which receptor is involved (α vs β, muscarinic vs nicotinic) for mechanism and side-effects.
Remember the balance between sympathetic and parasympathetic systems – many diseases or drug effects disturb this balance.
Think of what the body would do in fight/flight (symp) vs rest/digest (parasymp) – then predict what the drug will mimic or block.
For practical use: know the key examples (bethanechol, atropine, salbutamol, propranolol) and their indications and side-effects.
In your “practical” sessions you will often be asked: “which drug would you use for X condition?” (e.g., urinary retention → bethanechol; bradycardia induced by overdose → atropine).
Also important: drug interactions and contraindications (e.g., β-blockers in asthma risk bronchospasm; anticholinergics in glaucoma worsen it).
Because of vastness, I’ll summarise the major categories with key points and examples. For each category: classification, mechanism (brief), major drugs, indications, key side-effects.
Mechanism: Increase CNS activity (e.g., through catecholamine release, blocking reuptake).
Examples: Amphetamines, methylphenidate (for ADHD), caffeine.
Indications: ADHD, narcolepsy, sometimes obesity (less common now).
Side-effects: Insomnia, tachycardia, hypertension, dependence.
Key student point: Recognise that stimulants increase alertness, treat sleepiness and inattentiveness.
Mechanism: Depress CNS activity – varying depth from mild sedation to sleep induction to full anaesthesia.
Classification & examples:
Benzodiazepines (e.g., diazepam, lorazepam) – sedative/tranquiliser/hypnotic.
Non-benzodiazepine hypnotics (e.g., zolpidem).
Barbiturates (less used now).
Indications: Anxiety, insomnia, pre-operative sedation, seizures (some).
Side-effects: Drowsiness, dependence, respiratory depression (especially with alcohol or opioids), cognitive impairment.
Key student point: Distinguish sedative/tranquilliser (reduce anxiety) vs hypnotic (induce sleep) vs anaesthetic (loss of consciousness).
Mechanism: Various (block sodium channels, enhance GABA, inhibit calcium channels).
Examples: Phenytoin, carbamazepine, valproate, lamotrigine.
Indications: Epilepsy (various types), sometimes mood stabilisation.
Side-effects: Ataxia, sedation, hepatotoxicity (valproate), blood dyscrasias (carbamazepine), teratogenicity.
Key student point: Know which drug for generalised vs focal seizures; monitor hepatic/haematologic side-effects.
Mechanism: Increase availability of serotonin, norepinephrine, dopamine; anxiolytics usually enhance GABA or block anxiety circuits.
Examples: SSRIs (fluoxetine), SNRIs (venlafaxine), TCAs (amitriptyline), benzodiazepines (for anxiety).
Indications: Depression, anxiety disorders, sometimes chronic pain.
Side-effects: Sexual dysfunction (SSRIs), weight gain, sedation (TCAs), withdrawal (benzodiazepines), serotonin syndrome (when combined).
Key student point: SSRIs are first-line for depression; anxiolytics for short-term use; avoid long-term benzodiazepine dependence.
Mechanism: Inhibit prostaglandin synthesis (e.g., COX inhibitors) → reduce pain/inflammation/fever.
Examples: Paracetamol (acetaminophen), ibuprofen, aspirin.
Indications: Mild/moderate pain, fever, inflammation (mild).
Side-effects: Gastric irritation/ulcer (NSAIDs), liver damage (paracetamol overdose), bleeding (aspirin).
Mechanism: Bind µ-opioid receptors in CNS → inhibit pain pathways.
Examples: Morphine, codeine, tramadol.
Indications: Moderate to severe pain.
Side-effects: Respiratory depression, constipation, dependence, sedation, nausea.
Mechanism: Block COX1/COX2 → reduce prostaglandins.
Examples: Ibuprofen, naproxen, diclofenac.
Indications: Pain, inflammation (arthritis, gout), fever.
Side-effects: GI bleeding, renal impairment, cardiovascular risk (some).
Mechanism: Glucocorticoids → suppress multiple inflammatory pathways (cytokines, prostaglandins, leukotrienes).
Examples: Prednisone, dexamethasone.
Indications: Severe inflammation (autoimmune disease, asthma exacerbation), immunosuppression.
Side-effects: Hyperglycaemia, immunosuppression, osteoporosis, adrenal suppression, weight gain.
Key student point: Distinguish analgesic vs anti-inflammatory; know when opioids vs non-opioids; NSAIDs carry GI/renal/cardiac risks; steroids carry many systemic side-effects.
Rheumatology/gout:
Drugs for gout: e.g., allopurinol (xanthine oxidase inhibitor), colchicine.
Drugs for rheumatoid arthritis and other rheumatic diseases: NSAIDs, steroids, disease-modifying antirheumatic drugs (DMARDs – methotrexate), biologics (beyond diploma scope maybe).
Rigidity & Tremor Controllers (e.g., Parkinson’s disease):
Dopaminergic agents (levodopa), dopamine agonists (pramipexole), anticholinergics (trihexyphenidyl) for tremor, rigidity.
Key student point: Know gout drug mechanism; tremor/rigidity controllers often adjust dopaminergic/anticholinergic balance in CNS.
Local Anaesthetics: e.g., lidocaine – block sodium channels locally to stop nerve conduction.
General Anaesthetics: e.g., propofol, inhalational agents (sevoflurane) – various mechanisms producing loss of consciousness, analgesia, muscle relaxation.
Skeletal Muscle Relaxants:
Depolarising (succinylcholine) – neuromuscular block at NMJ.
Non-depolarising (rocuronium) – block ACh at NMJ.
Opioid Analgesics in Anaesthesia: Provide analgesia, sedation; e.g., fentanyl.
Key student point: Understand which agents are used for local vs general anaesthesia; muscle relaxants allow surgery; opioids augment anaesthesia.
For your practical sessions: you may be asked to choose a drug for a scenario (e.g., anaesthesia for surgery: general anaesthetic + muscle relaxant; gout acute attack: colchicine + NSAID; tremor in Parkinson’s: trihexyphenidyl).
Also expect dose, side-effects, monitoring parameters (e.g., opioids → monitor respiratory rate; NSAIDs → monitor kidney function & GI bleed; antidepressants → monitor mood changes, suicidal ideation).
Clinical correlations: always link mechanism → clinical effect → side-effect (and contraindications).
Use flowcharts and tables to summarise: e.g., analgesic ladder, classification of antiepileptics by mechanism, classification of antidepressants by generation.
Thyroid agents are drugs that either replace thyroid hormones (in hypothyroidism) or inhibit thyroid hormone synthesis (in hyperthyroidism).
They help maintain normal metabolism, growth, and development.
Used in hypothyroidism (e.g., Hashimoto’s disease, post-thyroidectomy, or cretinism):
Levothyroxine (T₄) – synthetic T₄; drug of choice.
Liothyronine (T₃) – faster onset, shorter half-life.
Liotrix – combination of T₄ and T₃.
Desiccated thyroid – dried animal thyroid gland (rarely used).
Mechanism of Action:
→ Converted to T₃ → binds nuclear receptors → increases transcription of metabolic enzymes → ↑ basal metabolic rate.
Pharmacokinetics:
Absorption: oral (best on empty stomach).
Onset: slow (1–3 weeks).
Half-life: long (T₄ ≈ 7 days).
Indications:
Hypothyroidism
Myxedema coma (IV T₃)
Goiter (non-toxic)
Post-thyroidectomy therapy
Adverse Effects (overdose → hyperthyroid state):
Tachycardia, palpitations
Weight loss, tremor, heat intolerance
Insomnia, anxiety
Atrial fibrillation (elderly)
Contraindications:
Untreated adrenal insufficiency
Thyrotoxicosis
Caution in cardiac disease
Used in hyperthyroidism (e.g., Graves’ disease):
| Drug | Mechanism | Notes |
|---|---|---|
| Propylthiouracil (PTU) | Inhibits thyroid peroxidase (TPO) + blocks peripheral T₄→T₃ conversion | Safe in 1st trimester pregnancy |
| Methimazole | Inhibits TPO (hormone synthesis only) | Longer half-life; contraindicated in 1st trimester |
| Carbimazole | Converted to methimazole | Similar profile |
Adverse Effects:
Agranulocytosis
Rash, urticaria
Hepatotoxicity (PTU)
Arthralgia
Other agents used in thyrotoxicosis:
Iodide (Lugol’s iodine, potassium iodide): inhibits hormone release.
Radioactive iodine (¹³¹I): destroys thyroid tissue.
Beta-blockers (Propranolol): control symptoms, inhibit T₄→T₃ conversion.
Glucocorticoids: reduce T₄→T₃ conversion and manage storm.
The parathyroid glands regulate calcium and phosphate via PTH (parathyroid hormone).
Disorders include hypoparathyroidism (↓PTH → hypocalcemia) and hyperparathyroidism (↑PTH → hypercalcemia).
Used in hypocalcemia / osteoporosis:
Teriparatide (PTH 1-34): recombinant PTH fragment – stimulates bone formation (intermittent use).
Abaloparatide: PTHrP analog, same action.
Adverse Effects:
Hypercalcemia, hyperuricemia, osteosarcoma risk (long-term).
Used in rickets, osteomalacia, renal osteodystrophy, hypocalcemia:
Cholecalciferol (D₃)
Ergocalciferol (D₂)
Calcitriol (1,25(OH)₂D₃): active form, used in renal failure.
Alfacalcidol: precursor activated in liver.
Mechanism: ↑ calcium & phosphate absorption from gut, ↓ renal excretion.
Used in hypocalcemia:
Calcium carbonate
Calcium citrate
Calcium gluconate (IV)
Used in secondary hyperparathyroidism (CKD) and parathyroid carcinoma:
Cinacalcet
Etelcalcetide (IV form)
Mechanism: Increases Ca-sensing receptor sensitivity → ↓ PTH secretion.
Adverse Effects: Hypocalcemia, nausea, vomiting.
Produced by thyroid C-cells; opposes PTH.
Drugs: Salmon calcitonin, human calcitonin.
Uses:
Hypercalcemia
Paget’s disease
Osteoporosis (less common now)
| Condition | Drug | Mechanism | Notes |
|---|---|---|---|
| Hypothyroidism | Levothyroxine | Hormone replacement | Monitor TSH |
| Hyperthyroidism | Methimazole / PTU | Block TPO | PTU in pregnancy |
| Hypocalcemia | Calcium + Calcitriol | Replace Ca/Vit D | Monitor ECG |
| Hypercalcemia | Calcitonin / Bisphosphonates / Cinacalcet | ↓ Bone resorption / ↓ PTH | IV fluids adjunct |
| Osteoporosis | Teriparatide / Denosumab | ↑ Bone formation | Intermittent PTH only |
Myxedema coma: IV levothyroxine + hydrocortisone.
Thyroid storm: PTU + propranolol + iodine + steroids.
Post-thyroidectomy tetany: IV calcium gluconate.
Chronic renal disease: use calcitriol + phosphate binders + cinacalcet.
Trophic hormonal therapies refer to treatments using hormones that stimulate the growth, function, or maintenance of target endocrine glands.
These hormones are secreted by the anterior pituitary gland and regulate other endocrine glands such as the thyroid, adrenal cortex, and gonads.
| Hormone | Target Gland | Main Effect | Therapeutic Use |
|---|---|---|---|
| TSH (Thyroid-Stimulating Hormone) | Thyroid gland | Stimulates thyroid hormone synthesis (T3, T4) | Diagnostic evaluation of thyroid function; rarely used therapeutically |
| ACTH (Adrenocorticotropic Hormone) | Adrenal cortex | Stimulates cortisol and androgens production | Used to test adrenal function (Cosyntropin test) |
| LH (Luteinizing Hormone) | Gonads | Stimulates ovulation and testosterone production | Used in infertility treatment |
| FSH (Follicle-Stimulating Hormone) | Gonads | Stimulates follicular development and spermatogenesis | Used in assisted reproduction (IVF) |
| GH (Growth Hormone) | Liver, bone, muscle | Stimulates growth and IGF-1 synthesis | Replacement in GH deficiency; anti-aging research |
| Prolactin | Mammary glands | Stimulates milk production | Dopamine antagonists may enhance its effect where indicated |
Trophic hormones act by binding to receptors on target gland cells → activate intracellular signaling cascades (e.g., cAMP, JAK-STAT pathways) → stimulate secretion of secondary hormones (like cortisol, estrogen, or thyroxine) → exert feedback inhibition on the pituitary and hypothalamus.
Endocrine replacement therapy: e.g., recombinant FSH, LH, GH.
Diagnostic testing: ACTH stimulation, TRH stimulation, GnRH stimulation.
Fertility therapy: hMG (human menopausal gonadotropin), hCG (human chorionic gonadotropin).
Growth disorders: recombinant GH for dwarfism.
Adrenal insufficiency evaluation: synthetic ACTH (Cosyntropin).
Hormone overproduction (iatrogenic hypersecretion)
Tumor growth stimulation in hormone-sensitive tissues
Electrolyte imbalance, hypertension, edema
Ovarian hyperstimulation syndrome (OHSS) with gonadotropin use
Active hormone-sensitive malignancies
Uncontrolled endocrine disorders (thyrotoxicosis, Cushing’s syndrome)
Pregnancy (for certain hormones)
| Category | Example | Brand Names | Use |
|---|---|---|---|
| GH analogs | Somatropin | Genotropin®, Norditropin® | GH deficiency |
| FSH analogs | Urofollitropin, Follitropin alfa | Bravelle®, Gonal-F® | Ovulation induction |
| LH analogs | Lutropin alfa | Luveris® | Ovulation induction |
| hCG | Chorionic gonadotropin | Pregnyl®, Ovidrel® | Mimics LH surge |
| ACTH analog | Cosyntropin | Cortrosyn® | Adrenal function test |
Biosynthetic trophic hormones with longer half-life
Gene therapy for pituitary hormone deficiencies
Combination hormone regimens for enhanced endocrine recovery
AI-guided hormonal titration in reproductive and growth medicine
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