BLACK BOX WARNING
- contraindicated in heart failure — cilostazol and similar PDE3 inhibitors have caused decreased survival in patients with class III-IV heart failure
cilostazol
Brand: Pletal
⚠ BBW Prototype: aspirin
Drug Class: antiplatelet agent — phosphodiesterase III inhibitor
Drug Family: antiplatelet
Subclass: PDE3 inhibitor with vasodilatory and antiplatelet properties
Organ Systems: cardiovascular
Mechanism of Action
Selectively inhibits PDE3, the cAMP-specific phosphodiesterase in platelets and vascular smooth muscle, elevating intracellular cAMP; in platelets, elevated cAMP inhibits aggregation; in vascular smooth muscle, it causes vasodilation — together improving walking distance in peripheral arterial disease.
phosphodiesterase III (PDE3)platelet cAMPvascular smooth muscle cAMP
Indications
- symptomatic intermittent claudication (peripheral arterial disease)
Contraindications
- heart failure of any severity (black box warning — class effect of PDE3 inhibitors)
- known hypersensitivity
- hemostatic disorders
Adverse Effects
Common
- headache
- diarrhea
- palpitations
- dizziness
- abnormal stools
Serious
- increased mortality risk in heart failure
- tachyarrhythmias
- hemorrhage
Pharmacokinetics (ADME)
| Absorption | oral; take on empty stomach (food increases Cmax by 90%); bioavailability approximately 70% |
| Distribution | Vd approximately 480 L; highly protein bound (>95-98%) |
| Metabolism | extensive hepatic CYP3A4 (primary) and CYP2C19; active metabolites contribute to efficacy |
| Excretion | renal (~74%) and fecal (~20%) |
| Half-life | 11-13 hours |
| Onset | 2-4 weeks for walking distance improvement |
| Peak | 2-3 hours |
| Duration | clinical improvement over weeks of treatment |
| Protein Binding | 95-98% |
| Vd | approximately 480 L |
Drug Interactions
| Drug / Agent | Mechanism | Severity |
|---|---|---|
| CYP3A4 inhibitors (erythromycin, diltiazem, ketoconazole) | increase cilostazol plasma levels; reduce dose to 50 mg twice daily | major |
| CYP2C19 inhibitors (omeprazole, esomeprazole) | increase active metabolite levels | moderate |
| antiplatelet agents and anticoagulants | additive bleeding risk | moderate |
Nursing Considerations
- Administer on an empty stomach (30 minutes before or 2 hours after meals); food significantly increases drug absorption and risk of adverse effects including palpitations.
- Inform patients that therapeutic improvement in walking distance typically requires 2-4 weeks of consistent therapy; adherence should be emphasized during this latency period.
- Assess cardiac status before and during therapy; cilostazol is absolutely contraindicated in patients with any degree of heart failure — screen for symptoms of HF (dyspnea, orthopnea, peripheral edema) at every visit.
- Monitor for palpitations and tachyarrhythmias; instruct patients to report any rapid or irregular heartbeat to their healthcare provider promptly.
Clinical Pearls
- Cilostazol is the only FDA-approved pharmacological therapy for symptomatic improvement of intermittent claudication, improving maximal walking distance by approximately 50% compared with placebo.
- The class contraindication in heart failure derives from the increased mortality seen with other PDE3 inhibitors (milrinone, amrinone) in heart failure trials; cilostazol was never studied in HF but shares the mechanism-based risk.
Safety Profile
Pregnancy use-with-caution
Lactation avoid
Renal Adjustment Not required
Hepatic Adjustment Not required
TDM Not required
Concordance Terms
Cross-referenced clinical concepts — click any term to see all content where it appears.