Cardiovascular (Nitrates)

Question 1

Examples of drugs (Nitrates)

Answer 1

• Isosorbide Mononitrate

- Glyceryl Trinitrate (GTN)

Question 2

Mechanism of action (Nitrates)

Answer 2

• Converted to Nitric Oxide (NO), a potent vasodilator.
• Cardioselective, acting predominantly on coronary blood vessels, enhancing flow of blood to ischaemic areas of the myocardium.
• Additionally, reduces myocardial oxygen consumption by reducing cardiac preload and afterload.

Question 3

Indications (Nitrates)

Answer 3

• Treatment of Angina

- Severe hypertension (intravenous GTN is sometimes used in this setting)

Question 4

Side-effects (Nitrates)

Answer 4

• Headache (incidence varies greatly, between 20-82%, causing cessation of treatment in 10%)
• Postural Hypotension / Dizziness
• Tachycardia

Question 5

Important pharmacokinetics/pharmacodynamics (Nitrates)

Answer 5

• Tolerance develops with long-term use.
• ## In order to avoid tolerance, patients should have a daily nitrate-free period.Isosorbide Mononitrate: Oral medication, longer duration of action than GTN.
• GTN: Rapidly inactivated by first pass (hepatic) metabolism and therefore cannot be digested – sublingual spray/tablet only. It can also be given intra-venously.

Question 6

Patient information (Nitrates)

Answer 6

• Headache is a common side effect initially, but incidence decreases the longer the patient is on the drug.
• Take GTN before activity that you know will bring on angina.