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