Is cilostazol safe to use in patients with current or prior heart failure?

Cilostazol is Contraindicated in Heart Failure

Cilostazol should NOT be used in patients with heart failure of any severity. This is an absolute contraindication mandated by the FDA with a black-box warning, based on the drug's mechanism as a phosphodiesterase-3 (PDE-3) inhibitor 1.

Rationale for Contraindication

The prohibition stems from class effect concerns with PDE-3 inhibitors. Other drugs in this class (milrinone, vesnarinone) have demonstrated increased mortality in heart failure patients with reduced ejection fraction 2. While cilostazol trials have not directly shown increased cardiovascular mortality (0.6% vs 0.5% on placebo in >2000 patients followed for 6 months), the FDA mandated the black-box warning as a precautionary measure pending more definitive long-term safety data 2.

Evidence Regarding Heart Failure Subtypes

Heart Failure with Reduced Ejection Fraction (HFrEF)

• Absolute contraindication - no exceptions 1
• Class effect from other PDE-3 inhibitors showing excess mortality 2

Heart Failure with Preserved Ejection Fraction (HFpEF)

The evidence here is more nuanced but still concerning:

• One recent 2025 RCT (CLIP-HFpEF) showed short-term improvements in KCCQ scores and NT-proBNP levels in 23 HFpEF patients, with reduced pulmonary artery pressures via heart rate increases 3
• However, a 2018 case-crossover study of 47,506 diabetic patients found cilostazol associated with 35% increased risk of heart failure hospitalization (OR: 1.35,95% CI: 1.14-1.59) 4
• The FDA label makes no distinction between HFrEF and HFpEF - the contraindication applies to "heart failure of any severity" 1

Prior Heart Failure (Currently Compensated)

• The contraindication applies regardless of current compensation status 1
• One retrospective analysis of Stanford clinical data found no increased mortality in CHF patients who received cilostazol despite the black-box warning, but this was observational data mining, not a prospective trial 5

Clinical Implications

For patients with peripheral arterial disease and any history of heart failure:

1. Do not prescribe cilostazol - the black-box warning is absolute 6, 2, 6, 2, 7, 8, 9, 1

2. Alternative therapies include:

   • Supervised exercise therapy (Class I recommendation) 6, 2, 7
   • Pentoxifylline as second-line (though marginal benefit) 2, 7, 8
   • Endovascular intervention if lifestyle-limiting 6, 7

3. If cilostazol is already prescribed: Verify heart failure status at every visit, as the 2024 pharmacovigilance data shows cardiac disorders rank highest among adverse events, with cardiac failure being the most reported 10

Common Pitfall

The most dangerous pitfall is assuming the contraindication only applies to "severe" or "symptomatic" heart failure. The FDA label explicitly states "heart failure of any severity" 1. This includes:

• NYHA Class I-IV
• HFrEF and HFpEF
• Prior heart failure now compensated
• Asymptomatic left ventricular dysfunction

Even though cilostazol improves walking distance by 40-60% in claudication patients 6, 2, 6, 2, 7, this benefit cannot justify the mortality risk in heart failure patients given the class effect of PDE-3 inhibitors.