In a review of safety data from efficacy trials and a long-term phase IV safety study (CASTLE), cilostazol was shown to increase heart rate by about 5–7 beats per minute, increasing the likelihood of cardiac events in at-risk patients.
Consequently, the PDE3 inhibitor must only be used as second-line treatment where lifestyle modifications (such as smoking cessation and exercise regimens) and other appropriate interventions have failed to provide sufficient improvement alone.
Cilostazol is also now contraindicated in patients with any of the following:
- unstable angina, recent myocardial infarction or coronary intervention (within 6 months)
- history of severe tachyarrhythmia
- receiving two or more other antiplatelet or anticoagulant agents
Prescribers should advise patients to take cilostazol 30 minutes before breakfast and the evening meal. A dose reduction to 50mg twice daily is now recommended when cilostazol is taken in combination with erythromycin, clarithromycin, ketoconazole, itraconazole, omeprazole or any strong inhibitors of CYP3A4 or CYP2C1.
New patients should be assessed after 3 months of treatment and discontinuation considered if there is no clinically relevant improvement in walking distance. Those currently receiving long-term treatment with cilostazol should be reassessed at their next routine appointment, in order to determine the need for ongoing treatment, dose change or withdrawal.