Cilostazol: A review of its use in intermittent claudication

Cilostazol (Pletal®) is a selective inhibitor of phosphodiesterase-III with antiplatelet, antithrombotic and vasodilating properties. It also exhibits antiproliferative effects on smooth muscle cells and has beneficial effects on high density lipoprotein-cholesterol and triglyceride levels. Randomized, double-blind, placebo-controlled 12-to 24-week trials in >2000 patients with moderate to severe intermittent claudication demonstrated that cilostazol generally significantly increased walking distances and improved quality of life compared with placebo. Additionally, a large comparative 24-week trial showed that cilostazol 100mg twice daily was significantly more effective than pentoxifylline 400mg three times daily (pentoxitylline was not significantly different from placebo). Cilostazol was generally well tolerated. Adverse events reported significantly more often with cilostazol than with placebo included headache, diarrhea, abnormal stools, infection, rhinitis and peripheral edema and in comparison with pentoxifylline were headache, diarrhea, abnormal stools and palpitations. Adverse events were generally mild to moderate in intensity, transient or resolved after symptomatic treatment and rarely required treatment withdrawal. Significant drug interactions are observed when cilostazol is coadministered with other agents that inhibit cytochrome P450 (CYP) 3A4 (e.g. erythromycin or diltiazem) or CYP2C19 (e.g. omeprazole). As a result, in Europe cilostazol is contraindicated in patients receiving CYP3A4 or CYP2C19 inhibitors and in the US it is recommended that dosage reduction for cilostazol be considered during coadministration of cilostazol and CYP3A4 or CYP2C19 inhibitors. Conversely, cilostazol itself does not appear to inhibit CYP3A4. Coadministration of cilostazol with aspirin or warfarin did not result in any clinically significant changes to coagulation parameters, bleeding time or platelet aggregation. Conclusion: In six of eight well designed clinical trials, cilostazol was significantly more effective than placebo in increasing walking distances and improving the quality of life of patients with moderate to severe intermittent claudication. In addition, limited comparative data have shown that cilostazol has superior efficacy compared with pentoxifylline. Cilostazol is also generally well tolerated. Additional comparative trials are required to confirm these results, to determine the place of cilostazol in relation to other agents or exercise therapy and risk factor reduction alone, and to establish the effects of long-term treatment with cilostazol in patients with intermittent claudication. Cilostazol is contraindicated in several subpopulations of patients, particularly those with congestive heart failure and severe hepatic or renal impairment. Nonetheless, current data support the choice of cilostazol as a promising therapy amongst the limited options available for patients with intermittent claudication.