Anti-Hypertensive Drugs Flashcards
What are the classes of anti-hypertensive drugs?
- Diuretics
- Beta blockers
- Vasodilators
- Mineralocorticoid antagonists
- Alpha 2 or imidazoline receptor agonist
What are the types of anti-hypertensive vasodilators?
- Calcium channel blockers
- Alpha 1 blockers
- Angiotensin converting enzyme inhibitors (ACEi)
- Angiotensin receptor blockers (ARB)
What is the mechanism of action of thiazide diuretics?
Thiazide diuretics work by inhibiting sodium reabsorption at the beginning of the kidney’s distal convoluted tubule (DCT) by blocking the thiazide-sensitive Na+-Cl− symporter
What is an example of a thiazide diuretic and what condition is it used for?
Bendrofluazide, used in hypertension (although recent NICE guidelines now recommend other thiazide-like diuretics such as indapamide and chlortalidone)
What is the mechanism of action of loop diuretics?
Loop diuretics act by inhibiting the Na-K-Cl cotransporter in the kidney’s thick ascending limb of the loop of Henle, reducing the absorption of NaCl.
What is an example of a loop diuretic and what conditions is it used for?
Furosemide, used in heart failure, both acute (usually intravenously) and chronic (usually orally) and resistant hypertension
What are some side effects of diuretics?
- Hypokalaemia, resulting in tiredness
- Arrhythmias
- Hyperglycaemia, resulting in diabetes
- Increase in uric acid, resulting in gout
- Impotence (erectile dysfunction)
What is the mechanism of action of beta blockers?
Blocking of beta 1 and beta 2 adrenoceptors
Which receptors do cardioselective beta blockers act on?
Only block beta 1 receptors
Which receptors do non-selective beta blockers act on?
Block both beta 1 and beta 2 receptors
What are examples of cardioselective beta blockers and what conditions are they used for?
Examples :
- Atenolol
- Bisoprolol
Used for :
- Angina
- Acute coronary syndrome
- Myocardial infarction
- Hypertension
- Heart failure
What are examples of non selective beta blockers and what conditions are they used in?
Examples :
- Propanolol
- Carvedilol
Used in :
- Thyrotoxicosis
- Migraine
What is special about carvedilol?
It is both an alpha and beta blocker
What are some side effects of beta blockers?
- Bronchospasm
- Tiredness
- Cold peripheries
- Erectile dysfunction
- Sleep disturbances (including nightmares)
In what conditions are beta blockers contraindicated?
Asthma and uncontrolled heart failure (beta blockers can worsen heart failure in the short term, especially cardiogenic shock)
What are the types of calcium channel blockers?
- Dihydropyridines
- Rate limiting calcium channel blockers
What is the mechanism of action of calcium channel blockers?
Calcium channel blockers block the inward movement of calcium by binding to the L-type “long-acting” voltage-gated calcium channels in the heart, vascular smooth muscle, and pancreas
What is an example of a dihydropyridine, what conditions is it used for and what is a notable side effect?
- Example : Amlodipine
- Used in hypertension and angina
- Side effect : Ankle oedema
What are examples of rate limiting calcium channel blockers, what conditions are they used in, and what medication should they not be used alongside?
Examples :
- Verapamil
- Diltiazem
Used in :
- Hypertension
- Angina
- Supraventricular arrhythmias (AF, SVT)
Avoid use with beta blockers
What is the mechanism of action of ACE inhibitors?
ACE inhibitors block angiotensin I becoming angiotensin II
What are examples of ACE inhibitors?
Lisinopril and ramipril
What conditions are ACE inhibitors used in?
- Hypertension
- Heart failure
What are the effects of ACE inhibitors on the kidneys?
- Good for kidneys in diabetic nephropathy
- Bad for kidneys in renal artery stenosis
What are some side effects of ACE inhibitors?
- Cough
- Renal dysfunction
- Angioneurotic oedema
In what situation should ACE inhibitors never be used?
Pregnancy induced hypertension
What is the mechanism of action of ARBs?
ARBs block angiotensin II receptors
What is an example of an ARB?
Losartan
What conditions are ARBs used in?
- Hypertension
- Heart failure
What are the effects of ARBs on the kidneys?
- Good for kidneys in diabetic nephropathy
- Bad for kidneys in renal artery stenosis
What are some side effects of ARBs?
- Renal dysfunction
- NO cough (in contrast to ACEi)
In what situation should ARBs never be used?
Pregnancy induced hypertension
What is the mechanism of action of alpha blockers?
Alpha blockers block alpha adrenoceptors to cause vasodilation
What is an example of an alpha blocker, what conditions is it used in and what is a notable side effect?
- Example : Doxazosin
- Used in hypertension and prostatic hypertrophy
- Side effect : Postural hypotension
What is the mechanism of action of mineralocorticoid antagonists?
Mineralocorticoid antagonists block aldosterone receptors
What are examples of mineralocorticoid antagonists, what conditions are they used in and what are some side effects?
Examples :
- Spironolactone
- Eplerenone
Used in :
- Heart failure
- Resistant hypertension
Side effects :
- Gynaecomastia
- Hyperkalaemia
- Renal impairment
What are clonidine and moxonidine?
- Alpha 2 adrenoceptor / imidazoline receptor agonists
- Centrally acting drugs - lower heart rate and blood pressure
