Cilostazol for Peripheral Artery Disease
Cilostazol 100 mg orally twice daily is the first-line pharmacologic therapy for patients with lifestyle-limiting intermittent claudication due to peripheral artery disease, provided they do not have heart failure of any severity. 1
Dosing
- Standard dose: 100 mg orally twice daily 1, 2, 3
- Reduced dose: 50 mg twice daily may be considered if patients experience intolerable adverse effects, though this dose is less effective 2
- Dose adjustment: Consider reducing to 50 mg twice daily when co-administered with strong CYP3A4 inhibitors (erythromycin, diltiazem) or CYP2C19 inhibitors (omeprazole) 4
- Duration for trial: Assess patient tolerance at 2-4 weeks and evaluate benefit within 3-6 months to determine if long-term therapy is warranted 5
Mechanism and Efficacy
Cilostazol is a phosphodiesterase III inhibitor that increases cyclic adenosine monophosphate, producing vasodilatory and antiplatelet effects. Five prospective randomized trials demonstrated that cilostazol improves maximal walking distance by 40-60% compared to placebo after 12-24 weeks of therapy 2. The drug also modestly improves ankle-brachial index (ABI) and quality of life measures 2, 5.
Absolute Contraindications
Heart failure of any severity is an absolute contraindication 3. This FDA black-box warning exists because other phosphodiesterase III inhibitors (milrinone, vesnarinone) have caused increased mortality in heart failure patients 2. Additional contraindications include:
- Active pathologic bleeding (bleeding peptic ulcer, intracranial bleeding) 3
- Hemostatic disorders 3
- Known hypersensitivity to cilostazol or its components 3
Common Adverse Effects
The most frequent side effects requiring monitoring include:
- Headache (most common; odds ratio 2.83 vs placebo) 6
- Diarrhea and abnormal stools 2
- Palpitations 2
- Dizziness 2
- Peripheral edema 4
Approximately 20% of patients discontinue cilostazol within 3 months due to adverse effects 5. These effects are generally mild to moderate, transient, and rarely require treatment withdrawal 4.
Monitoring Requirements
- Baseline assessment: Confirm absence of heart failure before initiating therapy
- Early follow-up: Evaluate tolerance at 2-4 weeks
- Efficacy assessment: Reassess walking distance and symptoms at 3-6 months 5
- Bleeding risk: Monitor for bleeding events, particularly in patients on concurrent antiplatelet or anticoagulant therapy (though serious bleeding rates were similar to placebo in long-term studies) 7
- Drug interactions: Screen for CYP3A4 and CYP2C19 inhibitors
Alternative Therapies
When cilostazol is contraindicated or not tolerated:
Pentoxifylline (Second-Line)
- Dose: 400 mg orally three times daily 1
- Efficacy: Marginal and not well-established; improves pain-free walking distance by only 21-29 meters and maximal walking distance by 43-48 meters 2
- Evidence: One head-to-head trial showed no significant difference between pentoxifylline and placebo, while cilostazol was superior to both 2
- Tolerability: Generally well tolerated with gastrointestinal side effects 2
Supervised Exercise Training (Preferred Non-Pharmacologic)
- Regimen: 30-45 minutes per session, at least 3 times weekly for minimum 12 weeks 1
- Evidence level: Class I recommendation (Level of Evidence: A) 1
- Note: Unsupervised "go home and walk" advice has minimal supporting data and is not well-established as effective 2
Therapies NOT Recommended (Class III)
- L-arginine: Effectiveness not well established 1
- Propionyl-L-carnitine: Effectiveness not well established 1
- Ginkgo biloba: Marginal and not well established 1
- Chelation therapy (EDTA): Not indicated and may have harmful adverse effects 1, 8, 1
- Vitamin E: Not recommended 8
Additional Clinical Considerations
Emerging indication: Recent evidence suggests cilostazol may reduce restenosis after femoropopliteal endovascular interventions. In patients undergoing bare-metal or drug-eluting stent placement in the femoropopliteal segment, cilostazol improved primary patency and reduced target lesion revascularization at 12.5 months follow-up 5.
Cardiovascular safety: Long-term data from over 2000 patients followed for up to 6 months showed cardiovascular death rates of 0.6% with cilostazol versus 0.5% with placebo, demonstrating no safety signal for increased mortality 2. The CASTLE study confirmed no increased all-cause or cardiovascular mortality with extended follow-up 7.
Lipid effects: Cilostazol increases HDL cholesterol and decreases triglyceride concentrations, which may provide additional cardiovascular benefit 2.