Essential Hypertension Drug Therapy
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Direct answer
Essential hypertension is persistently raised blood pressure with no identifiable secondary cause. Drug therapy starts with an ACE inhibitor or angiotensin receptor blocker, a dihydropyridine calcium channel blocker or a thiazide-type diuretic, chosen for compelling indications and comorbidities. Most patients need two drugs, and the target is at least below 140 over 90 mmHg, and about 130 over 80 where tolerated, as in diabetes or kidney disease.
What you must remember
- Staging: on the JNC 7 and ESC-style grading used in most Indian texts, stage 1 is systolic 140 to 159 or diastolic 90 to 99 mmHg, and stage 2 is systolic 160 or above or diastolic 100 or above; home or ambulatory readings confirm stage 1 disease before treatment in most patients.
- First-line classes: ACE inhibitors or ARBs, amlodipine among calcium channel blockers, and thiazide-like diuretics such as chlorthalidone or indapamide; beta blockers are second-line unless a compelling indication exists.
- Compelling indications: ACE inhibitor or ARB for diabetes with albuminuria and proteinuric chronic kidney disease; beta blockers after myocardial infarction, in angina and in heart failure; mineralocorticoid antagonists for resistant hypertension and heart failure with reduced ejection fraction.
- Combinations: start with two drugs when pressure is 20 over 10 mmHg or more above target; single-pill combinations such as an ARB with amlodipine improve adherence and are widely prescribed in India.
- Never combine: an ACE inhibitor with an ARB raises hyperkalaemia and renal injury without mortality benefit, as the ONTARGET trial showed.
- Safety: ACE inhibitors and ARBs are contraindicated in pregnancy; non-dihydropyridine calcium channel blockers are avoided in heart failure with reduced ejection fraction; thiazides cause hyperuricaemia and hyponatraemia.
- Monitoring: potassium and creatinine are checked one to two weeks after starting ACE inhibitors, ARBs or mineralocorticoid antagonists; angioedema requires permanent withdrawal of the ACE inhibitor.
A worked example in an outpatient clinic
A 55-year-old man with type 2 diabetes has home readings averaging 166 over 102 mmHg, raised urine albumin excretion and an eGFR around 60.
- Stage and find the indication. He is stage 2 by pressure, and diabetes with albuminuria supplies a compelling indication for renal protection, which points to an ARB or ACE inhibitor first.
- Start two drugs. His pressure is more than 20 over 10 mmHg above a sensible target, so starting two drugs is justified, and a low-dose ARB with amlodipine is a logical combination.
- Check the safety bloods. Blood pressure, potassium and creatinine are checked within one to two weeks, because an ARB can cause hyperkalaemia, and a modest creatinine rise is often accepted if the trajectory is stable.
- Escalate by documented need. If pressure stays above target on two drugs at maximum tolerated doses, a thiazide-like diuretic is the usual third agent.
- Screen for secondary causes. Resistance to three drugs triggers a screen for secondary causes and the addition of spironolactone.
- Add the parallel measures. Statin therapy, lifestyle change and smoking cessation proceed alongside the drugs.
Had he been a woman planning pregnancy, the ARB would be replaced by labetalol, nifedipine or methyldopa.
Where the exam tries to catch you
Four traps recur in hypertension questions, and each one reflects an outdated habit.
- Trap: starting a beta blocker as first line in uncomplicated hypertension, a habit inherited from older textbooks. Correct: reserve beta blockers for compelling indications such as ischaemic heart disease, heart failure and arrhythmias.
- Trap: lumping the ACE inhibitor cough and angioedema together. Correct: cough is a class effect that prompts a switch to an ARB, whereas angioedema of the tongue or lips means never rechallenging with another ACE inhibitor.
- Trap: prescribing an ACE inhibitor or ARB in pregnancy because they are first line otherwise. Correct: they are teratogenic and contraindicated, and labetalol, nifedipine or methyldopa are the accepted alternatives.
- Trap: choosing a fixed-dose pill for convenience alone. Correct: combinations improve adherence, but each component must independently suit the patient first.
Frequently asked questions
Which drug classes are first-line for essential hypertension?
ACE inhibitors or angiotensin receptor blockers, dihydropyridine calcium channel blockers such as amlodipine, and thiazide-like diuretics are first-line for essential hypertension. Beta blockers are second-line unless a compelling indication such as ischaemic heart disease or heart failure is present.
Which antihypertensive classes are unsafe in pregnancy?
ACE inhibitors and angiotensin receptor blockers are contraindicated in pregnancy because they cause fetal renal damage and developmental harm. Labetalol, nifedipine or methyldopa are the accepted alternatives for pregnant women with hypertension.
When should two antihypertensive drugs be started together?
Starting two drugs together is recommended when blood pressure is 20 over 10 mmHg or more above target, because it reaches control faster and improves adherence. Single-pill combinations are often used for convenience once both components suit the patient.
Why should ACE inhibitors and ARBs not be combined?
Combining an ACE inhibitor with an ARB increases hyperkalaemia, hypotension and acute kidney injury without reducing mortality, as shown in the ONTARGET trial. Dual blockade is therefore avoided in routine hypertension care.