What is the starting oral dose of phentermine/topiramate?

• A. 3.75 mg/23 mg
• B. 7.5 mg/46 mg
• C. 15 mg/92 mg
• D. 1 mg/8 mg

Answer: (A)

Starting with a low dose helps balance the desire to reduce appetite with tolerability for side effects. The initial oral dose is phentermine 3.75 mg combined with topiramate 23 mg, taken once daily in the morning. This modest amount minimizes cognitive effects that topiramate can cause and reduces stimulant-related symptoms such as jitteriness or increased heart rate, while still providing early weight-loss benefits. If this is tolerated well for about two weeks, the dose is typically increased to 7.5 mg/46 mg daily for more substantial weight loss, with further increases only as needed and guided by tolerance. Safety notes important for any patient include avoiding use during pregnancy and discussing contraception, since topiramate can cause fetal harm, and monitoring for common side effects like paresthesias, dry mouth, and mood changes.