How do nitrates work in angina management?

How do nitrates work in angina management?

• A. They release nitric oxide to dilate blood vessels
• B. They block beta receptors
• C. They inhibit ACE
• D. They increase heart rate

Answer: (A)

Nitrates relieve angina by releasing nitric oxide, which dilates vascular smooth muscle. When nitrates release NO, it activates a signaling pathway that increases cyclic GMP, causing relaxation of the smooth muscles in veins (and to some extent arteries). The result is venodilation that lowers venous return to the heart (preload) and reduces wall stress and myocardial oxygen demand. This helps lessen angina symptoms and can improve blood flow to ischemic areas as a secondary benefit from the overall reduction in oxygen demand. In practice, short-acting nitrates provide immediate relief for an acute attack, while longer-acting nitrates are used for ongoing prophylaxis, with attention to tolerance and potential side effects like headaches or hypotension. This mechanism is distinct from blocking beta receptors, inhibiting ACE, or intentionally increasing heart rate. Those actions belong to other drug classes, and while nitrates can cause a reflex tachycardia due to lowered blood pressure, their primary therapeutic effect is not to raise heart rate.

Nitrates relieve angina by releasing nitric oxide, which dilates vascular smooth muscle. When nitrates release NO, it activates a signaling pathway that increases cyclic GMP, causing relaxation of the smooth muscles in veins (and to some extent arteries). The result is venodilation that lowers venous return to the heart (preload) and reduces wall stress and myocardial oxygen demand. This helps lessen angina symptoms and can improve blood flow to ischemic areas as a secondary benefit from the overall reduction in oxygen demand. In practice, short-acting nitrates provide immediate relief for an acute attack, while longer-acting nitrates are used for ongoing prophylaxis, with attention to tolerance and potential side effects like headaches or hypotension.

This mechanism is distinct from blocking beta receptors, inhibiting ACE, or intentionally increasing heart rate. Those actions belong to other drug classes, and while nitrates can cause a reflex tachycardia due to lowered blood pressure, their primary therapeutic effect is not to raise heart rate.