Double-Blind Study of Papaverine Hydrochloride on the Efficacy in the Treatment of Intermittent Claudication

Abstract

A double-blind, placebo-controlled, parallel groups study design was utilized to evaluate the efficacy and the safety of papaverine HCL (PA, 300- 1,500 mg/day) in the treatment of intermittent claudication. The study was in two phases: Phase I-6 weeks duration with treadmill claudication tests and doppler ankle/brachial pressure studies every 2 weeks to establish disease stability; Phase II-12 weeks double-blind evaluation of PA versus placebo (PL) with treadmill claudication tests and doppler ankle/brachial pressure studies every 4 weeks. Intermittent claudication was documented by symptoms, his tory and objective evidence of decreased blood supply to the lower ex tremities : decreased resting and post-exercise ankle/brachial pressure indices (A/B Pr), diminished segmental pulse-volumes and physical findings. Data were collected to determine the distance to initial pain (IP), rapidly increasing pain (RIP) and absolute claudication (AC) during treadmill tests and also the changes in resting and post-exercise A/B Pr. In 20 patients who completed this study, the distance to RIP was increased 43% by PA and decreased 2% by PL (p=0.012). PA increased the distance to AC by 29%, but was decreased by 1% in PL (p=0.039). The A/B Pr studies showed significant less decrease in 1 minute and 2.5 minutes post exercise A/B Pr at 12 weeks in PA patients as compared to those in PL patients.