Onset of Action: Naftidrofuryl and Cilostazol
Both naftidrofuryl and cilostazol require 3 months of continuous therapy to demonstrate clinically meaningful improvements in walking distance for intermittent claudication, with neither drug providing immediate symptom relief.
Naftidrofuryl Onset of Action
- Clinical trials demonstrate that naftidrofuryl 600-633 mg/day requires 3 to 6 months of oral therapy to significantly increase pain-free walking distance compared to placebo 1
- The drug must be taken in divided doses (either 3 or 2 times daily) throughout this period to achieve therapeutic benefit 1
- There is no evidence of acute or immediate symptom relief; the mechanism involving improved oxidative metabolism, transcutaneous oxygen pressure, and rheological properties requires sustained administration 1
Cilostazol Onset of Action
- Cilostazol 100 mg twice daily similarly requires evaluation at 24 weeks (approximately 6 months) to assess therapeutic efficacy 2
- The drug should be taken 30 minutes before or 2 hours after breakfast and dinner, with clinical benefit accumulating over months rather than days or weeks 3
- As a phosphodiesterase III inhibitor affecting cyclic adenosine monophosphate-mediated responses, cilostazol's antiplatelet, vasodilatory, and antiproliferative effects develop gradually 3
Clinical Implications
- Patients must be counseled that neither medication provides rapid symptom relief and adherence for at least 3 months is necessary before determining treatment efficacy 1, 2
- Walking distance improvements are measured at 24-week endpoints in clinical trials, establishing this as the minimum timeframe for therapeutic assessment 2, 4
- Both medications showed significant improvements in maximal walking distance only after sustained therapy: naftidrofuryl increased walking distance by 71.2 m (95% CI 13.3-129.0 m) and cilostazol by 41.3 m (95% CI -7.1-89.7 m) compared to placebo, but these benefits were measured after months of treatment 5