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