Antihypertensives

Question 1

Calcium Channel Blockers (Verapamil, Amlodipine): Mechanism of Action

Answer 1

Selectively L-Type CCB reducing transport of Ca decreasing excitation-contraction coupling - negative inotropy, vasodilatation, depress SA/AVN.

Arteriolar dilators
Negative inotropic effect (increase cardiac output)
Interfere with excitation contraction coupling and so decrease the force of contraction

Question 2

Calcium Channel Blockers (Verapamil, Amlodipine): Effects

Answer 2

Arteriolar dilators
Negative inotropic effect (increase cardiac output)
Interfere with excitation contraction coupling and so decrease the force of contraction

Reduce myocardial oxygen consumption as well` as increasing oxygen supply through coronary dilation to treat Angina.
Also used to treat hypertension particularly in elderly patients

Question 3

Calcium Channel Blockers (Verapamil, Amlodipine): Side Effects

Answer 3

Not just vascular smooth muscle also gastrointestinal, uterine and bronchiolar tissues.
Hypotension
Bradycardia
Oedema

Question 4

Calcium Channel Blockers (Verapamil, Amlodipine): Cautions

Answer 4

Hepatic or renal impairment

Question 5

Calcium Channel Blockers (Verapamil, Amlodipine): Drug Dose

Answer 5

Amlodipine 5-10 mg/day PO

Verapamil 80 mg PO

Question 6

Spironolactone: Mechanism of Action

Answer 6

Aldosterone antagonists – prevents nuclear translocation of the mineralcorticoid receptor

That is, it is an antagonist of the mineralocorticoid receptor (MR), the biological target of mineralocorticoids like aldosterone and 11-deoxycorticosterone.[5] By blocking the MR, spironolactone inhibits the effects of mineralocorticoids in the body.[5]

(Spironolactone is a moderate antiandrogen.[111][130][153] That is, it is an antagonist of the androgen receptor (AR), the biological target of androgens like testosterone and dihydrotestosterone (DHT).[111][130][153] By blocking the AR, spironolactone inhibits the effects of androgens in the body.)

Question 7

Spironolactone: Effects/ Clinical Use

Answer 7

Oedema in congestive heart failure
Hypertension

Decreases circulating volume

Question 8

Spironolactone: Side Effects

Answer 8

urinary frequency
Hyperkalaemia
Gastrointestinal
In men gynecomastia

Question 9

Spironolactone: Cautions/Contraindications

Answer 9

Addison’s disease; anuria; hyperkalaemia, Pregnancy

Question 10

Spironolactone: Dose

Answer 10

25mg OD PO

Relatively week so used in combination with other diuretics to prevent hypokalaemia

Question 11

Amiloride: Mechanism of Action

Answer 11

Direct inhibition of Na+ permeability in the collecting duct by competitive inhibition of ENaC CT

Question 12

Amiloride: Effects/ Clinical Use

Answer 12

Decreases circulating volume

Question 13

Amiloride: Side Effects

Answer 13

Hyperkalaemia

Gastrointestinal

Question 14

Amiloride: Cautions/Contraindications

Answer 14

Addison’s disease; anuria; hyperkalaemia

Question 15

Amiloride: Dose

Answer 15

5mg OD PO

Question 16

ACE inhibitor (e.g. Ramipril, Lisinopril): Mechanism of Action

Answer 16

Blocks the cleavage of Angiotensin I to Angiotensin II by ACE. This also decreases ADH release and aldosterone production thus reducing Na+ reabsorption

Question 17

ACE inhibitor (e.g. Ramipril, Lisinopril): Effects/ Clinical Use

Answer 17

Mixed vasodilator
Inhibits degredatio of bradykinin increasing vasodilation
Decrease systemic arterial pressure
Facilitate natiuresis 
Limits ventricular remodelling

Question 18

ACE inhibitor (e.g. Ramipril, Lisinopril): Side Effects

Answer 18

Dry Cough
Hyperkalaemia
Hypotension
- agranulocytosis

Question 19

ACE inhibitor (e.g. Ramipril, Lisinopril): Cautions/Contraindications

Answer 19

Afro-Caribbean patients (may respond less well to ACE inhibitors);
use with caution in hepatic and renal impairment

Question 20

ACE inhibitor (e.g. Ramipril, Lisinopril): Dose

Answer 20

Initially 1.25–2.5 mg once daily, increased if necessary up to 10 mg OD

Question 21

ARBs (e.g. Losartan, Valsartan, Candesartan): Mechanism of Action

Answer 21

Antagonise action of angiotensin II at AT1 receptor

Question 22

ARBs (e.g. Losartan, Valsartan, Candesartan): Effects/ Clinical Use

Answer 22

Less effective vasodilator than ACEi but used in chronic heart failure when ACE inhibitors are unsuitable or contra-indicated (They do not inhibit the breakdown of bradykinin or other kinins, and are thus only rarely associated with the persistent dry cough and/or angioedema that limit ACE inhibitor therapy)

Benefit for sever heart failure and may also prevent against stroke
Also used in hypertension
Blockage of AT1 receptors directly causes vasodilation, reduces secretion of vasopressin, and reduces production and secretion of aldosterone, among other actions. The combined effect reduces blood pressure.

Question 23

ARBs (e.g. Losartan, Valsartan, Candesartan): Side Effects

Answer 23

Abdominal pain; asthenia; back pain; cough; diarrhoea; dizziness; headache; hyperkalaemia; hypotension;

anemia

Question 24

ARBs (e.g. Losartan, Valsartan, Candesartan): Cautions/Contraindications

Answer 24

thrombocytopenia/bilateral renal artery stenosis and pregnancy
Afro-Caribbean patients—particularly those with left ventricular hypertrophy (may not benefit from an angiotensin-II receptor antagonist); aortic or mitral valve stenosis;

Question 25

List 3 Beta Blockers

Answer 25

Atenolol, bisoprolol, timolol, carvedilol, propranolol