Class
ACE Inhibitors
Examples
Enalapril, Ramipril, Lisinopril
Mechanism
Inhibit angiotensin-converting enzyme, reducing angiotensin II formation
Key Adverse Effects
Dry cough, angioedema, hyperkalaemia
NotesAll Years (1st-Final)All UniversitiesAntihypertensive
Antihypertensive Drugs Classification Chart for MBBS
Antihypertensive drug classification is one of the most frequently tested topics in Pharmacology, and it resurfaces again in General Medicine case discussions in Final Year. This chart organises the major drug classes by mechanism, with representative examples and key adverse effects, for quick exam revision. This is a study reference for exam preparation, not a prescribing guide. Actual drug choice and dosing in practice depend on patient-specific factors and current clinical guidelines.
SME-reviewed. Updated 2026.
Open GeckoMed for Pharmacology notes, PYQs, and viva prep in one place.Antihypertensive Drug Classes
| Class | Examples | Mechanism | Key Adverse Effects |
|---|---|---|---|
| ACE Inhibitors | Enalapril, Ramipril, Lisinopril | Inhibit angiotensin-converting enzyme, reducing angiotensin II formation | Dry cough, angioedema, hyperkalaemia |
| Angiotensin Receptor Blockers (ARBs) | Losartan, Telmisartan, Valsartan | Block angiotensin II at the AT1 receptor | Hyperkalaemia, dizziness, generally lower cough incidence than ACE inhibitors |
| Beta Blockers | Atenolol, Metoprolol, Propranolol | Block beta-adrenergic receptors, reducing heart rate and cardiac output | Bradycardia, bronchospasm, fatigue |
| Calcium Channel Blockers | Amlodipine, Nifedipine, Diltiazem | Block L-type calcium channels, causing vasodilation | Ankle oedema, flushing, headache |
| Diuretics | Hydrochlorothiazide (thiazide), Furosemide (loop), Spironolactone (potassium-sparing) | Reduce circulating blood volume through renal sodium and water excretion | Electrolyte imbalance, hypokalaemia (except potassium-sparing agents) |
| Alpha Blockers | Prazosin | Block alpha-1 adrenergic receptors, causing vasodilation | Postural hypotension, first-dose syncope |
| Centrally Acting Agents | Methyldopa, Clonidine | Reduce sympathetic outflow from the central nervous system | Sedation, dry mouth, rebound hypertension on abrupt withdrawal |
| Direct Vasodilators | Hydralazine | Directly relax vascular smooth muscle | Reflex tachycardia, lupus-like syndrome |
Class
Angiotensin Receptor Blockers (ARBs)
Examples
Losartan, Telmisartan, Valsartan
Mechanism
Block angiotensin II at the AT1 receptor
Key Adverse Effects
Hyperkalaemia, dizziness, generally lower cough incidence than ACE inhibitors
Class
Beta Blockers
Examples
Atenolol, Metoprolol, Propranolol
Mechanism
Block beta-adrenergic receptors, reducing heart rate and cardiac output
Key Adverse Effects
Bradycardia, bronchospasm, fatigue
Class
Calcium Channel Blockers
Examples
Amlodipine, Nifedipine, Diltiazem
Mechanism
Block L-type calcium channels, causing vasodilation
Key Adverse Effects
Ankle oedema, flushing, headache
Class
Diuretics
Examples
Hydrochlorothiazide (thiazide), Furosemide (loop), Spironolactone (potassium-sparing)
Mechanism
Reduce circulating blood volume through renal sodium and water excretion
Key Adverse Effects
Electrolyte imbalance, hypokalaemia (except potassium-sparing agents)
Class
Alpha Blockers
Examples
Prazosin
Mechanism
Block alpha-1 adrenergic receptors, causing vasodilation
Key Adverse Effects
Postural hypotension, first-dose syncope
Class
Centrally Acting Agents
Examples
Methyldopa, Clonidine
Mechanism
Reduce sympathetic outflow from the central nervous system
Key Adverse Effects
Sedation, dry mouth, rebound hypertension on abrupt withdrawal
Class
Direct Vasodilators
Examples
Hydralazine
Mechanism
Directly relax vascular smooth muscle
Key Adverse Effects
Reflex tachycardia, lupus-like syndrome
Quick Recall: ABCD
A widely used clinical mnemonic for the major first-line antihypertensive drug classes.
| Letter | Stands For |
|---|---|
| A | ACE inhibitors (and ARBs) |
| B | Beta blockers |
| C | Calcium channel blockers |
| D | Diuretics |
Letter
A
Stands For
ACE inhibitors (and ARBs)
Letter
B
Stands For
Beta blockers
Letter
C
Stands For
Calcium channel blockers
Letter
D
Stands For
Diuretics
For more memory aids like this, see the Pharmacology Mnemonics PDF.
How This Appears in Exams
- Short answer questions such as "Classify antihypertensive drugs with examples"
- Viva questions asking you to name the mechanism and adverse effects of a specific class
- Case-based questions in General Medicine linking a patient's comorbidities to an appropriate drug class, such as avoiding beta blockers in asthma
- Applied questions on why ACE inhibitors are avoided in pregnancy, or why methyldopa is preferred in pregnancy-induced hypertension
Frequently Asked Questions
Which MBBS year covers antihypertensive drug classification?
Pharmacology is a 2nd Year MBBS subject, so this classification is first taught then. It resurfaces in General Medicine case discussions in Final Year.
Is this chart useful for clinical prescribing?
No. This chart is compiled as an MBBS study and exam reference. Actual prescribing decisions in practice depend on patient-specific factors and current clinical guidelines, and should not be based on a study chart.
Which class is typically first-line for most patients?
ACE inhibitors, ARBs, calcium channel blockers, and thiazide diuretics are generally considered first-line options, though the appropriate choice depends on patient-specific factors such as comorbidities and pregnancy status. Refer to your pharmacology and medicine textbooks for exam-specific guideline positions.
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