13.01.24 Pharmacology lecture - HTN

Unusual causes of HTN

    • Acromegaly

      • Also raises glucose

    • NSAIDs

    • Pheochromocytoma (cf MEN IIa)

      • => HTN, flushing, sweating

      • May cause hypercalcaemia (but may be due to concurrent hyperparathyroidism in MEN IIa)

      • Risk of death! Must exclude

Liddle's syndrome

    • Autosomal dominant disorder characterized by early, and frequently severe, hypertension

    • Looks like hyperadosteronism

      • Low plasma renin activity

      • Metabolic alkalosis due to hypokalemia

      • But normal to low levels of aldosterone

    • Involves abnormal kidney function

      • Caused by dysregulation of an epithelial sodium channel (ENaC)

    • Treatment

      • Low sodium diet

      • Potassium-sparing diuretic that directly blocks the sodium channel

        • Amiloride or triamterene

      • Spironolactone is not effective because it acts by regulating aldosterone and Liddle syndrome does not respond to this regulation

CCB cardiac selectivity order

    • Varapamil

    • Diltiazem

    • Amlodipine

    • Nifedipine

    • Felodipine

    • Nicardipine

    • Lercanidipine

Side effects

    • CCBs

      • Ankle swelling

      • Gingival hyperplasia

    • Diuretics

      • Gout

      • Impotence

    • ACEi

      • Impotence

      • Cough

      • Renal impairment if renal artery stenosis

Contraindications

    • CCBs

      • Heart failure

    • ACEi

      • Pregnancy

      • Renal artery stenosis

    • Diuretics

      • CKD

    • Beta blockers

      • Asthma

    • Alpha blockers

      • Almost none - Very safe!

Notes

    • Carcinoid

      • => Tachycardia but NOT HTN

      • Test 5-HIAA

    • Bilateral adrenal hyperplasia is more common than adrenal adenoma as a cause of hyperaldosteronism

    • Beading of renal arteries

      • Sign of fibromuscular dysplasia

      • Can cause HTN

    • Lifestyle measures are at least as good as one drug

    • Aged, black => CCB

      • Then A+C

      • Then A+C+D

    • Aliskiren = Direct renin inhibitor

    • Losartan is now off-patant

      • => First choice, as there's no cough

      • However half-life is only 2 hours (but can still take OD)

    • ACEi/ARB help protect kidneys in HTN if there's concurrent diabetes or nephropathy