Continuous transdermal nitroglycerin patch therapy loses its antianginal efficacy within 24 to 48 hours. The recommended strategy to prevent this tolerance is:
- A Increase the patch dose threefold
- B Add a long-acting oral nitrate simultaneously
- C Provide a 10 to 12 hour nitrate-free interval each day ✓
- D Co-administer hydralazine
Correct answer: C. Provide a 10 to 12 hour nitrate-free interval each day
Explanation
Nitrate tolerance results from depletion of reduced sulfhydryl groups needed for biotransformation of nitrates to nitric oxide, along with volume expansion and neurohormonal activation. A daily nitrate-free interval of 10 to 12 hours restores responsiveness and is the standard recommendation in Katzung. Increasing the dose or stacking another nitrate worsens tolerance. Hydralazine increases NO bioavailability but this combination is established in heart failure, not for preventing patch tolerance.
Reference: Katzung's Basic and Clinical Pharmacology, 16th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.