Drugs Used In Angina Pectoris and Myocardial Infarction Question And Answers

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Drugs Used In Angina Pectoris and Myocardial Infarction Important Notes

1. Classification of nitrates

  • Short-acting
    • Glyceryl trinitrate
    • Nitroglycerine
  • Long-acting
    • Isosorbide dinitrate
    • Isosorbidemononitrate

2. Isosorbidemononitrate

  • Long-acting
  • Undergoes little first-pass metabolism
  • Bioavailability is high

3. Nitrates

  • Its most prominent action is exerted on vascular smooth muscle
  • It dilates veins more than arteries
  • Causes peripheral pooling of blood
  • This decreases venous return
  • Decrease load on the heart

4. Nitroglycerine

  • Used by sublingual route
  • Acts within 1-2 min as it is directly absorbed into the systemic circulation

Drugs Used In Angina Pectoris and Myocardial Infarction Long Essays

Question 1. Classify vasodilators. Describe the pharmacol¬ogical actions of nitrates, their clinical uses, and side effects.

Answer:

Classification of Vasodilators:

1. Arteriolar dilators – decreases afterload.

  • Hydralazine, Nifedipine, Nicorandil.

2. Venodilators – Decreases preload.

  • Nitrates – Glyceiyl trinitrate, isosorbide dinitrate.

3. Mixed dilators – Decreases both pre and after-load.

  • ACE inhibitors, prazosin, sodium nitroprusside.

Read And Learn More: Pharmacology Question and Answers

Nitrates:

  • Nitrates are prodrugs.

Actions:

1. Preload reduction.

Nitrates dilates veins
↓
Causes peripheral pooling of blood
↓
Decreases venous return
↓
Reduces preload.

2. Afterload reduction.

Nitrates dilate arteries.
↓
Decreases vascular resistance
↓
Decreases afterload.

  • Decreases in preload afterload result in a decrease in cardiac workload.

3. Redistribution of coronary flow.

  • Nitrates relax bigger conducting coronary arteries.
  • Causes redistribution of blood flow to ischaemic areas in angina pectoris.

4. Other vasculature.

  • Dilates cutaneous vessels → causes flushing.
  • Dilates meningeal vessels → causes headache.

Question 2. Enumerate four antianginal drugs that belong to different groups. Write the mechanism of action.

Answer:

Anti-anginal drugs Classification:

1. Nitrates.

  • Short-acting – Glyceryl trinitrate, Nitroglycerine.
  • Long-acting – Isosorbide dinitrate, Isosorbide mononitrate.

2. Beta blockers.

  • Propranolol, Metoprolol, Atenol.

3. Calcium channel blockers.

  • Verapamil, Diltiazem, Nifedipine.

4. Potassium channel opener- Nicorandil.

5. Others

  • Dipyridamole, Trimetazidine.

Short-Acting Drugs – Nitrates:

  • Short-acting drugs are among nitrates.

Mechanism of Action:

Denitration of organic nitrates in the smooth muscle cells.
↓
Releases reactive free radical nitric oxide.
↓
Causes activation of cytosolic guanylyl cyclase.
↓
Increases cGMP
↓
Causes dephosphorylation of myosin light chain kinase
(MLCK)
↓
This interferes with the activation of myosin.
↓
Myosin fails to interact with actin.
↓
No contraction occurs, thus it causes relaxation.

Drugs Used In Angina Pectoris and Myocardial Infarction Short Essays

Question 1. List one cardioselective and one nonselective beta-blocker. Mention two therapeutic uses of them.

Answer:

1. Cardioselective beta blocker:

  • They selectively block the bl receptor and weakly the b2 receptor.
  • Their inhibition of glycogenolysis is low.
  • Impairs exercise performance to a lesser degree.

Cardioselective Beta Blocker Uses:

  • Safer is diabetics
  • Cardiac arrhythmia.
  • Angina pectoris.
  • Hypertension.

Cardioselective Beta Blocker Examples:

  • Atenolo, metoprolol and esmolo.

2. Non-selective beta blockers.

Non-Selective Beta Blockers Uses:

  • Glaucoma.
  • Anxiety
  • Pheochromocytoma.
  • Thyrotoxicosis.
  • Prophylaxis of migraine.

Non-Selective Beta Blockers Examples:

  • Timolol, propranolol, nadolol, sotalol.

Drugs Used In Angina Pectoris and Myocardial Infarction Short Answers

Question 1. Nitroglycerine.

Answer:

Nitroglycerine is a short-acting antianginal drug.

Nitroglycerine Mechanism:

Conversion of nitroglycerine to nitric oxide.
↓
Causes relaxation of vascular smooth muscles
↓
Leads to vasodilation.
↓
Reduces venous return and preload on the heart

Nitroglycerine Pharmacokinetics:

  • Effective sublingually.
  • Well absorbed from buccal mucosa.

Nitroglycerine Uses:

  • Angina
  • Cardiac failure
  • Myocardial infarction.
  • Cyanide poisoning.

Question 2. Name drugs causing gingival hyperplasia.

Answer:

Drugs causing gingival hyperplasia:

1. Anticonvulsants.

  • Phenytoin sodium – phenobarbitone, carbamazepine.

2. Antihypertensive-nifedipine, amlodipine, nimodipine.

3. Immunosuppressants – cyclosporine.

Question 3. Name organic nitrates used in the treatment of angina pectoris.

Answer:

Organic nitrates used in the treatment of angina pectoris are.

1. Short acting-Glyceryl trinitrate Nitroglycerine.

2. Long-acting – Isosorbide dinitrates, isosorbide mononitrate.

Question 3. Angina pectoris

Answer:

Angina pectoris is a pain syndrome due to the induction of an adverse oxygen supply-demand situation in a portion of a myocardium.

Angina pectoris Forms:

1. Classical/Stable angina.

  • The attack is provoked by exercise, emotion, and eating.
  • In it, blood flow fails to increase during increased demand despite dilatation of resistance vessels and pain occurs.

2. Variant angina.

  • Attacks occur at rest or during sleep.
  • Occurs due to recurrent localized coronary vaso-spasm in the presence of atherosclerotic coronary artery disease.

Drugs Used In Angina Pectoris and Myocardial Infarction Viva Voce:

1. Nitroglycerine is used by the sublingual route

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