CV - Nicorandil

Question 1

Nicorandil

Common indications

Answer 1

• For prevention and treatment of chest pain in people with stable angina.
• First choice treatments for stable angina are β-blockers and calcium channel blockers, individually or in combination.
• Nicorandil (or a long-acting nitrate) may be used if these drugs are insufficient or not tolerated.

Question 2

Nicorandil

Mechanisms of action

Answer 2

• Nicorandil causes both arterial and venous vasodilatation through its actions as a nitrate (see Nitrates) and by activating K+-ATP channels.
• Efflux of K+ through activated K+-ATP channels leads to hyperpolarisation of the cell membrane and subsequent inactivation of voltage-gated Ca2+ channels.
• The net effect is a decrease in free intracellular calcium. As calcium is required for smooth muscle contraction, relaxation and vasodilatation occur.
• The effect of this is to reduce cardiac preload and systemic and coronary vascular resistance.
• This improves myocardial perfusion, and decreases myocardial work and oxygen demand. Clinically, this reduces the frequency and severity of angina attacks.

Question 3

Nicorandil

Important Adverse Affects

Answer 3

• Unwanted effects of vasodilatation include flushing, dizziness and headache. Nicorandil can also cause nausea, vomiting and hypotension.
• Less frequently, it can cause gastrointestinal, skin or mucosal ulceration, which only responds to withdrawal of treatment.

Question 4

Nicorandil

Warnings

Answer 4

• You should not routinely prescribe nicorandil for patients with poor left ventricular function, hypotension or pulmonary oedema, as it can worsen these conditions.
• As with nitrates, the hypotensive side effects of nicorandil are significantly enhanced by phosphodiesterase inhibitors (e.g. sildenafil). They should not be prescribed together.

Question 5

Nicorandil

Px and Administration

Answer 5

• Nicorandil is only available for oral administration.
• It is started at a low dose of 5–10 mg twice daily and increased to 20–30 mg twice daily as the patient becomes tolerant of the vasodilatory adverse effects.
• Advise the patient that nicorandil has been prescribed to reduce attacks of chest pain.
• Explain that they should take the treatment for the foreseeable future. Discuss other measures to reduce cardiovascular risk, including smoking cessation.
• Warn patients not to drive or use heavy machinery until angina symptoms are controlled and side effects of nicorandil, including dizziness and hypotension, have settled.