Angina drugs

Question 1

Classes of drugs used to treat angina

Answer 1

1. Nitrates (Glycerol nitrates, Isosorbide dinitrate)
2. Beta blockers
3. Ca2+ channel blockers (non DHP and DHP)
4. Ivabradine

Question 2

MOA of glycerol nitrates and Isosorbide dinitrate

Answer 2

• Vasodilator → decrease preload and afterload → decrease oxygen consumption (reduce DEMAND)

(NO activates guanylyl cyclase, increasing cGMP → inactivation of myosin LC)

Question 3

Clinical uses of nitrates

Answer 3

1. Nitroglycerin for the treatment of angina
2. ISDN and ISMN for prophylaxis as the onset of action is quite long (ISMN faster)

Also reduces end diastolic pressure → lowers intramural pressure → improvement to subendocardial flow → direct dilatory effect on coronary arteries

Question 4

Side effect of nitrates

Answer 4

Reflex tachycardia
Hypotension
Headache

Question 5

Examples of beta blockers

Answer 5

Non selective: propranolol, carvedilol

B1 selective: bisoprolol, metoprolol XL

Dose dependent: Nebivolol

Question 6

which class of drugs ends in -lol?

Answer 6

Beta blockers

Question 7

MOA of beta blockers

Answer 7

Decrease heart rate and contractility → reduce myocardial oxygen requirements

Question 8

MOA of Calcium channel blockers

Answer 8

Block the calcium channels to prevent influx of Ca2+ → prevent formation of Ca2+-calmodulin complex → no activation of MLCK → no Myosin-LC activation

Vasodilation –> reduce peripheral vascular resistance –> decrease workload of heart –> decrease demand of O2

Question 9

DHP or non DHP CCB used in angina treatment?

Answer 9

Both
DHP: Nifedepine, amlodipine
NDHP: Verapamil, Diltiazem

Question 10

What else is non DHP CCB used for?

Answer 10

Anti arrhythmics

Question 11

Clinical uses of CCB

Answer 11

1. Hypertension (lowers vascular smooth muscle tone)
2. Stable angina (amlodipine)
3. Reduce risk of myocardial infarction & stroke (amlodipine)

Question 12

Adverse effects of CCB

Answer 12

Hypotension
Heart failure
Myocardial infarction

Question 13

What are examples of CCB

Answer 13

DHP: Nifedipine, amlodipine
NDHP: Verapamil, Diltiazem

Question 14

MOA of Ivabradine

Answer 14

A ‘pure’ heart rate lowering agent

Inhibits cardiac pacemaker I(f) current that controls the spontaneous depolarisation in the SA node
Blocking this pacemaker → regulates heart rate → reduce workload of heart → reduce oxygen consumption

Question 15

Clinical uses of Ivabradine

Answer 15

1. Stable angina pectoris
2. HFrEF in patients in sinus rhythm whose heart rate is > 75bmp

Question 16

Adverse effects of Ivabradine

Answer 16

1. Visual problems: Luminous phenomena, transient enhanced brightness in a limited area of the visual field
2. Bradycardia – dizziness, hypotension, fatigue

Question 17

Do CCB work reduce cardiac muscle contractility directly or indirectly?

Answer 17

Indirectly. By reducing peripheral vascular resistance (vasodilation) and afterload, nifedipine can decrease the workload on the heart, leading to a reduction in cardiac oxygen demand.

Question 18

Which drug is used for long term therapy for variant angina aimed at reducing incidence or severity of the coronary vasospasm

Answer 18

Diltiazem