Nitrates treat angina by what mechanism and how is tolerance prevented?

• A. Venodilation decreasing preload; nitrate-free interval (8–12 hours daily) to prevent tolerance.
• B. Arterial dilation decreasing afterload; continuous use prevents tolerance.
• C. Vasoconstriction reducing venous return; no tolerance.
• D. Increase heart rate to improve perfusion; take with meals.

Answer: (A)