Nicorandil is a vasodilator that works Through a dual mechanism of action, functioning as both a potassium channel opener and a nitrate donor. This unique combination relaxes and widens blood vessels, which reduces the workload on the heart and increases its blood and oxygen supply.

Mechanism of action

1. Potassium channel activation: Nicorandil opens adenosine triphosphate-sensitive potassium (K_ATP) channels in the smooth muscle cells of blood vessel walls. This action leads to several effects:
   • Hyperpolarization: When K_ATP channels open, potassium ions (K⁺) flow out of the cell, making the cell’s membrane potential more negative (hyperpolarized).
   • Vascular smooth muscle relaxation: The hyperpolarization closes voltage-gated calcium channels, which decreases the amount of calcium (Ca²⁺) entering the cell. Lower intracellular calcium levels cause the smooth muscle to relax.
   • Reduced afterload: The relaxation of arterial walls causes vasodilation, which decreases the resistance the heart must pump against (afterload).
2. Nitrate donation: Nicorandil contains a nitrate component, giving it a nitrate-like effect.
   • Nitric oxide (NO) release: The nitrate part of the molecule stimulates the enzyme guanylate cyclase, which increases the production of cyclic guanosine monophosphate (cGMP).
   • Vasodilation: Elevated cGMP levels relax the vascular smooth muscle. This effect primarily dilates the large coronary arteries and veins.
   • Reduced preload: Venous dilation reduces the volume of blood returning to the heart, which in turn decreases the heart’s filling pressure (preload).

Expert advice for Nicorandil

• You must continue to take it as advised, usually for a long time.
• Nicorandil may cause headaches. Drink plenty of water and take a suitable painkiller. Inform your doctor if it does not go away.
• Nicorandil may cause dizziness or sleepiness. Do not drive or do anything which requires concentration until you know how it affects you.
• Do not consume alcohol while taking Nicorandil as that may cause increased dizziness.
• Do not take medications like sildenafil or tadalafil (prescribed for erectile dysfunction) while on treatment with Nicorandil as it may cause low blood pressure.
• Inform your doctor if you notice any bleeding from the anal passage, blood in vomit or black stools.