💊 Nicorandil

Nicorandil is an anti-anginal drug that acts as a potassium channel activator and a nitrate, providing both arterial and venous vasodilation.

It has a dual mechanism of action: it activates ATP-sensitive potassium channels in vascular smooth muscle, leading to hyperpolarisation and vasodilation. Additionally, it provides a nitrate-like effect by increasing intracellular cGMP, causing further vasodilation. This results in reduced preload and afterload, and improved coronary blood flow.

Nicorandil is indicated for the prevention and long-term treatment of stable angina pectoris in patients inadequately controlled by or intolerant to first-line anti-anginal therapies. It is particularly useful in patients with microvascular angina or those with contraindications to beta-blockers or calcium channel blockers.

Contraindications include cardiogenic shock, left ventricular failure with low filling pressure, and severe hypotension. Concomitant use with phosphodiesterase-5 (PDE5) inhibitors is an absolute contraindication due to the risk of profound hypotension. It should also be avoided in patients with a history of gastrointestinal ulcers.

Common side effects include headache, flushing, and dizziness, similar to other nitrates. However, nicorandil is particularly associated with ulceration, including oral, gastrointestinal, and perianal ulcers, which can be severe and require discontinuation. Hypotension and reflex tachycardia can also occur.

Patients should be monitored for the development of ulcers, particularly oral or gastrointestinal, and advised to report any such symptoms. Blood pressure should be monitored, especially at the start of treatment. Efficacy in reducing angina symptoms should be assessed.

When prescribing, specifically ask about any history of ulcers or inflammatory bowel disease. Counsel the patient about the potential for mouth sores or other ulcers and to report them immediately. Reiterate the absolute contraindication with PDE5 inhibitors and the risk of severe hypotension.

Nicorandil is unique due to its dual mechanism (K+ channel opener + nitrate). The most high-yield adverse effect is ulceration (oral, GI, perianal). It's a second-line anti-anginal. Remember the interaction with PDE5 inhibitors. Headaches are common.

SBA questions often highlight the dual mechanism of action (potassium channel activation and nitrate effect). A key trap is the association with severe ulceration (oral, GI, perianal), which differentiates it from other anti-anginals. The contraindication with PDE5 inhibitors is also a common theme.