Nicorandil
MECHANISM OF ACTION
- Dual mechanism of action.
- Opens ATP-sensitive Kþ channels resulting in smooth muscle relaxation, thereby promoting arterial vasodilatation and reducing afterload.
- Nitric oxide moiety activates guanylyl cyclase to achieve venous relaxation and a reduction in preload.
- Direct effects on coronary arteries are also seen.
INDICATIONS
- Prophylaxis and treatment of angina
CAUTIONS AND CONTRA-INDICATIONS
- Cardiogenic shock.
- Hypotension.
- LVF with poor filling pressures
SIDE-EFFECTS
- Headaches on initiation.
- Nausea and vomiting.
- Dizziness.
- Flushing.
- Weakness.
- Oral ulceration.
- Angioedema.
METABOLISM AND HALF-LIFE
- t½ is 40–80min. Metabolised by the liver via nicotinamide pathway; <20% excreted in the urine.
MONITORING
- Monitor clinically for adverse effects.
DRUG INTERACTIONS
- Hypotensive effects significantly enhanced when taken with phosphodiesterase type 5 inhibitors (e.g. sildenafil).
- Hypotensive effects possibly enhanced with tricyclic antidepressants and alcohol.
IMPORTANT POINTS
- Start at a lower dose in patients susceptible to headaches.
- Patients are advised not to drive or operate machinery until it is established that their performance is unaffected.
- Titrate dose to symptomatic relief.
- Used as an add-on therapy