Nitrates (isosorbide mononitrate)

Question 1

What is isosorbide mononitrate used for/

Answer 1

isosorbide mononitrate is a long acting nitrate that is used for prophylaxis of angina when a beta blocker or calcium channel blocker is not tolerated.

Question 2

How do nitrates work?

Answer 2

Nitrates are converted to nitric oxide (NO).
NO increases cyclic GMP synthesis and reduces Calcium in vascular smooth muscle cells causing them to relax.
This leads to vasodilation.
—-> Reduced preload and left ventricular filling —> reduced cardiac work and oxygen demand —-> less angina.

Question 3

What are the side effects of Nitrates?

Answer 3

flushing,
headaches,
light headedness,
hypotension,

Question 4

In what patients are nitrates contraindicated in?

Answer 4

• severe aortic stenosis
• haemodynamic instability
• hypotension

Question 5

What are the drug interactions of nitrates?

Answer 5

-phosphodiesterase inhibitors (prolong and enhance effect of nitrates)

Question 6

/What is the plasma half life of isosorbide mononitrate

Answer 6

4-5 hours

Question 7

What is the route of isosorbide mononitrate?

Answer 7

oral tablets (immediate release, modified release) or dermal patches

Question 8

How is the efficacy of nitrates monitored?

Answer 8

reduced breathlessness
relieved chest pain

(tolerance can develop with prolonged use)