Nitrates

Question 1

What are some examples of some nitrates

Answer 1

isosorbide mononitrate, glyceryl trinitrate

Question 2

What are the indications for use

Answer 2

• Short-acting nitrates (glyceryl trinitrate) used in Tx ACUTE ANGINA + chest pain ass w. ACUTE CORONARY SYND
• Long-acting nitrates (isosorbide mononitrate) - prophylaxis of ANGINA (where B-Blockers + CaCB insufficient)
• Intravenous nitrates in PULMONARY OEDEMA - in combo w. furosemide + O2

Question 3

What is their mechanisms of action

Answer 3

• Converted to nitric oxide (NO) –> increases cylic cGMP synthesis + reduced intracell Ca in vascular smooth muscle = relax
• Vasodilation - mainly venous
• Reduce preload + L ventricular filling = reduce cardiac work + myocardial O2 demand –> relieve angina + HF
• Can relieve coronary vasospams + dilate collateral vessels

Question 4

What are some important side effects

Answer 4

• Flushing, headache, light-headedness, hypotension (vasodilator)
• Sustained use can lead to tolerance

Question 5

What are some contra-indications

Answer 5

• Severe aortic stenosis (CV collapse- heart unable to increase CO through narrowed valve)
• Haemodynamic instability
• Hypotension

Question 6

What are some interactions

Answer 6

• Phosphodiesterase inhibitors (e.g. sildenafil) –> prolong + enhance hypotensive effects