Antihypertensives Flashcards
Name some ACEi
ramipril, Captopril, Enalapril, Lisinopril, Perindopril, Trandolapril.
MoA ACEi
competitive inhibitor of angiotensin converting enzyme (ACE)
Inhibits synthesis of potent vasoconstrictor peptide angiotensin II leading to vascular smooth
muscle relaxation and vasodilatation
Overall effect: Reduced blood pressure
indications ACEi
Hypertension (1st line drug in younger caucasian patients <55 years)
Heart failure and secondary prevention Post-MI
Type I Diabetic nephropathy
Following acute MI
Dosing ACEi
Starting dose: Hypertension 2.5 mg daily / 1.25mg daily in heartfailure or elderly
Maintenance dose: 10mg daily
Adverse effects ACEi COMMON
Persistent dry cough, hyperkalaemia, increase in serum creatinine
(First dose) hypotension – may be profound
Adverse effects ACEi important
Acute renal failure, cholestatic jaundice/hepatitis
Angioedema, hypersensitivity reactions
cautions and contraindications ACEi
caution: anything which could impact renal function wg renal impairment, diuretics
severe aortic stenosis
contraindictaed in pregnancy
interactions ACEi
Diuretics (increased risk of hypotension)
Potassium sparing diuretics (increased risk of hyperkalaemia) – amiloride, triamterene,
spironolactone, eplerenone
Potassium salts
Avoid co-prescription with ARBs candesartan etc. or Direct renin inhibitors – aliskiren
Lithium
Immunosuppressants – ciclosporin (increased risk of hyperkalaemia)
how do ace inhibitors cause hyperkalaemia
The blockade of angiotensin II prevents the downstream secretion of aldosterone
therapeutic drug monitoring ACEi
U&E before and 1-2 w after starting treatment
particularly looking at urea/creatinine and potassium levels for
signs of hyperkalaemia or deterioration in renal function.
patient communication ACEi
Explain the need for a blood test (U+E) before starting treatment and 1-2 weeks after treatment.
If
the patient devlops a dry cough within the first few months thenthey should report this to their GP
and their medication will be changed to an ARB.
If the patient is at risk of first dose hypotension (e.g.
elderly) then should take initial first dose at night.
name some ARBs
Candesartan, Losartan, Valsartan, Eprosartan,
Olmesartan, Telmisartan, irbesartan
MoA ARB
competitive antagonist of angiotensin II AT1 receptor
Selective inhibition of potent vasoconstrictor peptide angiotensin II leading to vascular
smooth muscle relaxation and vasodilatation
indications ARBs
Hypertension
Heart failure
Post-MI
Prevention of cardiovascular events in patients with established atherosclerotic
cardiovascular disease and/or diabetes mellitus with target-organ damage
Type II diabetic nephropathy
medication for diabetic nephropathy
both can have ACEi or ARB but ideal is:
type 1 diabetic - ACEi
type 2 diabetic - ARB (angiotensin 2!)
common adverse effects ARB
(First dose) hypotension – less marked than with ACE inhibitor, dizziness, hyperkalaemia,
increase in serum creatinine
contraindications and cautions ARB
Caution in aortic or mitral stenosis and in renal artery stenosis
Avoid in pregnancy & breast-feeding; do not prescribe to women of child bearing age if they
are trying to conceive.
important adverse effects ARB
Acute renal failure
Angioedema (may be delayed onset)
interactions ARBs
Other antihypertensives (increased hypotensive effect)
ACE inhibitors, Potassium sparing diuretics (increased risk of hyperkalaemia)
Lithium
therapeutic drug monitoring ARB
Renal function should be checked at baseline via U+E – this should be repeated 1-2 weeks
after starting treatment and annually thereafter.
Older patients and patients with heart failure
should also be closely monitored clinically.
what are the only scenarios where ARB is preffered over ACEi
- ACEi has caused persistent dry cough
- type 2 diabetic nephropathy
- afro-caribbean ethnicity eg second line HTN
name 4 dihydropyridine calcium channel blockers
amlodipine
nifedipine
felodipine
lercanidipine
MoA dihydropyridine calcium channel blockers
Target: L-type calcium channels - Dihydropyridines favour depolarised closed Ca++ channels most
commonly found in vascular smooth muscle cells
Action: Antagonist
Effect: Inhibit influx of calcium ions into vascular smooth muscle cells through L-type calcium
channels
Overall effect: Decreased arterial smooth muscle contratility leading to vasodilatation
MoA non-dihydropyridine calcium channel blockers
Target: L-type calcium channels - Diltiazem and Verapamil favour the hyperpolarised Ca++ channels
more commonly found in cardiac muscle cells
Action: Antagonist
Effect: Inhibit influx of calcium ions into cardiomyocytes through L-type calcium channels
Overall effect: Negative inotropic effect – decreases cardiac contractility
common adverse effects CCBs
Constipation on toilet
Flushed straining doing a poo
Straining causes a headache
Ankles swell up coz sat down for so long
Dizzy when you stand up
important adverse effects of CCBs
dihydropyridine = Heart failure in patients with poor left ventricular function
non-diydropyridine = Sino-atrial and AV block with diltiazem, particularly in those taking digoxin and/or beta
blockers
interactions CCBs dihydropyridine
Other antihypertensives (increased hypotensive effect)
Simvastatin – increased risk of myopathy therefore dose of statin should be reduced
Antiepileptics (reduced efficacy of dihydropyridines)
Digoxin (increased plasma digoxin concentration)
Theophylline (increased plasma theophylline concentration)
interactions CCBs non-dihydropyridine
Antihypertensives (increased hypotensive effect)
Beta blockers (asystole, severe hypotension, heart failure)
Anti-arrhythmics (increased risk of bradycardia, AV block and myocardial depression)
