The duration of action of ropinirole is 8 hours.

• A. 12 hours
• B. 8 hours
• C. 6 hours
• D. 4 hours

Answer: (B)

Duration of action reflects how long the drug continues to provide therapeutic effect, which for ropinirole’s immediate-release form is about eight hours. The half-life is around six hours, so the clinical effect generally lasts roughly eight hours. That makes eight hours the best match. A longer duration like twelve hours would exceed what's typical for the immediate-release form, while four hours would be shorter than expected. (Extended-release ropinirole can last about 24 hours, but this question refers to the standard form.)