Cilostazol side effects: what 6,130 FDA adverse event reports show
Drug class
Phosphodiesterase 3 Inhibitor
Who reports
6,130 reports · 82% serious · 979 with death outcome · 41% female
Used for
Cilostazol tablets are indicated for the reduction of symptoms of intermittent claudication, as demonstrated by an increased walking distance. Cilostazol is a phosphodiesterase III inhibitor (PDE III inhibitor) indicated for the reduction of symptoms of intermittent claudication, as demonstrated by an increased walking distance ( 1 )
What it is
Cilostazol is a quinolinone derivative that inhibits cellular phosphodiesterase (more specific for phosphodiesterase III).
Boxed warning
CONTRAINDICATED IN HEART FAILURE PATIENTS Cilostazol tablets are contraindicated in patients with heart failure of any severity. Cilostazol and several of its metabolites are inhibitors of phosphodiesterase III. Seve.
Causality screen of the 40 strongest signals
What the badges mean
- Labeled — boxed warning The term (or its clinical synonym) appears in the FDA boxed warning: causality is regulator-recognised and considered serious.
- Labeled adverse reaction The exact term appears in the label's warnings or adverse-reactions sections: a known, expected effect. The FAERS signal confirms the label rather than discovering anything.
- Labeled (related wording) The label describes this effect under different wording (e.g. 'neutropenia' for 'neutrophil count decreased'). Treated as known.
- Reporting / coding artifact An administrative, monitoring or exposure term (product issue, off-label use, 'test normal', overdose...). Not a biological reaction; a high PRR here reflects how reports are coded.
- Not in label — unassessed Not found in the label text, not an artifact pattern. This is a genuine candidate for a formal causality assessment (Bradford Hill / WHO-UMC); it has NOT had one here.
Strongest disproportionality signals
Flagged terms (PRR ≥ 2, χ² ≥ 4, n ≥ 10), ranked by PRR; infinite PRRs (no comparator reports) excluded. The EBGM column is a second, shrinkage-based estimate (MGPS) with its 5th percentile EB05 and the BCPNN IC025; a pair flagged by PRR alone is marked PRR-only and should be read as fragile. The strata column recomputes the PRR on serious reports only and flags pairs whose reports are unusually skewed by sex or come mostly from consumers rather than clinicians. 408 further terms are in the interactive explorer. Reaction links open the term's cross-drug page.
| Reaction | Reports | PRR 95% CI · ROR · χ²/p | EBGM EB05 · IC025 | Label screen | Serious-only & strata | Trial cross-check |
|---|---|---|---|---|---|---|
| Cerebral infarction | 117 | 16.4 13.7–19.7ROR 16.7 · χ² 1,674 / p <1e-300 | 16.3 EB05 14.0 · IC025 +3.6 3/3 methods agree | Labeled (related wording) related wording | serious PRR 10.9 · 92% clinician | no trial data cached |
| Ventricular fibrillation | 42 | 12.9 9.6–17.5ROR 13.0 · χ² 449 / p 5e-100 | 12.6 EB05 9.6 · IC025 +3.0 3/3 methods agree | Labeled (related wording) related wording | serious PRR 8.9 · ♀ 71% (drug 41%) · 100% clinician | no trial data cached |
| End stage renal disease | 48 | 8.9 6.7–11.8ROR 9.0 · χ² 330 / p 6e-74 | 8.5 EB05 6.6 · IC025 +2.6 3/3 methods agree | Not in label — unassessed | serious PRR 6.3 · ♀ 62% (drug 41%) | no trial data cached |
| Ventricular tachycardia | 41 | 8.5 6.2–11.5ROR 8.5 · χ² 263 / p 2e-59 | 7.9 EB05 6.0 · IC025 +2.4 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 5.6 | no trial data cached |
| Ventricular extrasystoles | 23 | 7.6 5.0–11.4ROR 7.6 · χ² 125 / p 3e-29 | 6.7 EB05 4.7 · IC025 +2.0 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 4.4 | no trial data cached |
| Upper gastrointestinal haemorrhage | 36 | 7.3 5.3–10.1ROR 7.3 · χ² 189 / p 2e-43 | 6.8 EB05 5.1 · IC025 +2.2 3/3 methods agree | Labeled (related wording) related wording | serious PRR 5.1 | no trial data cached |
| Subdural haematoma | 30 | 7.2 5.0–10.2ROR 7.2 · χ² 152 / p 2e-35 | 6.5 EB05 4.8 · IC025 +2.1 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 4.9 | no trial data cached |
| Subarachnoid haemorrhage | 20 | 6.7 4.3–10.4ROR 6.7 · χ² 91 / p 6e-22 | 5.9 EB05 4.0 · IC025 +1.8 3/3 methods agree | Not in label — unassessed | serious PRR 4.7 | no trial data cached |
| Melaena (black stool) | 42 | 6.5 4.8–8.8ROR 6.6 · χ² 191 / p 1e-43 | 6.1 EB05 4.7 · IC025 +2.1 3/3 methods agree | Not in label — unassessed | serious PRR 4.6 | no trial data cached |
| Hepatic function abnormal | 69 | 6.4 5.0–8.1ROR 6.4 · χ² 307 / p 4e-69 | 6.1 EB05 5.0 · IC025 +2.2 3/3 methods agree | Labeled (related wording) related wording | serious PRR 4.6 · 96% clinician | no trial data cached |
| Disseminated intravascular coagulation | 26 | 6.3 4.3–9.3ROR 6.3 · χ² 111 / p 3e-26 | 5.7 EB05 4.1 · IC025 +1.9 3/3 methods agree | Not in label — unassessed | serious PRR 4.1 · 91% clinician | no trial data cached |
| Chronic kidney disease | 141 | 6.3 5.4–7.4ROR 6.4 · χ² 625 / p 4e-138 | 6.2 EB05 5.4 · IC025 +2.3 3/3 methods agree | Not in label — unassessed | serious PRR 4.5 | no trial data cached |
| Pneumonia aspiration | 45 | 6.2 4.6–8.3ROR 6.2 · χ² 190 / p 1e-43 | 5.8 EB05 4.5 · IC025 +2.1 3/3 methods agree | Not in label — unassessed | serious PRR 4.4 | no trial data cached |
| Arteriosclerosis | 17 | 6.2 3.8–9.9ROR 6.2 · χ² 69 / p 6e-17 | 5.4 EB05 3.5 · IC025 +1.6 3/3 methods agree | Not in label — unassessed | serious PRR 4.5 | no trial data cached |
| Blood urea increased | 30 | 6.1 4.3–8.7ROR 6.1 · χ² 123 / p 8e-29 | 5.6 EB05 4.1 · IC025 +1.9 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 4.6 | no trial data cached |
| Acute myocardial infarction | 51 | 5.9 4.5–7.8ROR 5.9 · χ² 203 / p 3e-46 | 5.6 EB05 4.4 · IC025 +2.0 3/3 methods agree | Labeled (related wording) related wording | serious PRR 4.1 | no trial data cached |
| Interstitial lung disease | 81 | 5.7 4.6–7.1ROR 5.8 · χ² 313 / p 3e-70 | 5.6 EB05 4.6 · IC025 +2.1 3/3 methods agree | Labeled (related wording) related wording | serious PRR 4.0 | no trial data cached |
| Cerebral haemorrhage | 59 | 5.6 4.4–7.3ROR 5.7 · χ² 221 / p 3e-50 | 5.4 EB05 4.3 · IC025 +2.0 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 4.0 | no trial data cached |
| Gastric haemorrhage | 19 | 5.6 3.6–8.8ROR 5.6 · χ² 67 / p 1e-16 | 5.0 EB05 3.4 · IC025 +1.6 3/3 methods agree | Not in label — unassessed | serious PRR 4.1 | no trial data cached |
| Gastrointestinal haemorrhage | 131 | 5.3 4.5–6.3ROR 5.4 · χ² 458 / p 6e-102 | 5.2 EB05 4.5 · IC025 +2.1 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 3.8 | no trial data cached |
| Altered state of consciousness | 33 | 5.2 3.7–7.4ROR 5.3 · χ² 109 / p 8e-26 | 4.9 EB05 3.7 · IC025 +1.7 3/3 methods agree | Not in label — unassessed | serious PRR 3.7 · 93% clinician | no trial data cached |
| Shock | 34 | 5.1 3.6–7.1ROR 5.1 · χ² 108 / p 1e-25 | 4.8 EB05 3.6 · IC025 +1.7 3/3 methods agree | Not in label — unassessed | serious PRR 3.3 · 100% clinician | no trial data cached |
| Post procedural haemorrhage | 17 | 5.0 3.1–8.0ROR 5.0 · χ² 50 / p 7e-13 | 4.4 EB05 2.9 · IC025 +1.3 3/3 methods agree | Reporting / coding artifact | serious PRR 3.7 | no trial data cached |
| Coronary artery occlusion | 20 | 5.0 3.2–7.7ROR 5.0 · χ² 59 / p 6e-15 | 4.5 EB05 3.1 · IC025 +1.4 3/3 methods agree | Not in label — unassessed | serious PRR 3.5 | no trial data cached |
| Cardiomegaly | 18 | 5.0 3.1–7.9ROR 5.0 · χ² 53 / p 2e-13 | 4.4 EB05 3.0 · IC025 +1.4 3/3 methods agree | Not in label — unassessed | serious PRR 3.6 | no trial data cached |
| Tubulointerstitial nephritis | 27 | 4.9 3.4–7.2ROR 5.0 · χ² 81 / p 1e-19 | 4.6 EB05 3.3 · IC025 +1.6 3/3 methods agree | Not in label — unassessed | serious PRR 3.5 · ♀ 64% (drug 41%) | no trial data cached |
| Photosensitivity reaction (sun sensitivity) | 23 | 4.8 3.2–7.2ROR 4.8 · χ² 65 / p 4e-16 | 4.4 EB05 3.1 · IC025 +1.4 3/3 methods agree | Not in label — unassessed | serious PRR 5.3 · 91% clinician | no trial data cached |
| Haematoma | 36 | 4.7 3.4–6.6ROR 4.8 · χ² 102 / p 2e-24 | 4.5 EB05 3.4 · IC025 +1.6 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 3.3 | no trial data cached |
| Mitral valve incompetence | 15 | 4.5 2.7–7.5ROR 4.5 · χ² 38 / p 4e-10 | 4.0 EB05 2.6 · IC025 +1.2 3/3 methods agree | Not in label — unassessed | serious PRR 3.2 | no trial data cached |
| Skin ulcer | 34 | 4.5 3.2–6.3ROR 4.5 · χ² 89 / p 2e-21 | 4.3 EB05 3.2 · IC025 +1.5 3/3 methods agree | Not in label — unassessed | serious PRR 4.1 | no trial data cached |
| Angina pectoris | 37 | 4.4 3.2–6.1ROR 4.4 · χ² 94 / p 2e-22 | 4.2 EB05 3.2 · IC025 +1.5 3/3 methods agree | Labeled — boxed warning exact term | serious PRR 3.1 | no trial data cached |
| Osteomyelitis | 23 | 4.4 2.9–6.5ROR 4.4 · χ² 56 / p 4e-14 | 4.0 EB05 2.8 · IC025 +1.3 3/3 methods agree | Not in label — unassessed | serious PRR 3.1 | no trial data cached |
| Hyperglycaemia (high blood sugar) | 46 | 4.3 3.2–5.8ROR 4.4 · χ² 115 / p 4e-27 | 4.2 EB05 3.3 · IC025 +1.6 3/3 methods agree | Not in label — unassessed | serious PRR 3.5 | no trial data cached |
| Cardiac failure (heart failure) | 99 | 4.2 3.5–5.1ROR 4.3 · χ² 240 / p 2e-54 | 4.1 EB05 3.5 · IC025 +1.7 3/3 methods agree | Labeled — boxed warning synonym match | serious PRR 2.9 | no trial data cached |
| Hypoglycaemia (low blood sugar) | 59 | 4.2 3.2–5.4ROR 4.2 · χ² 139 / p 3e-32 | 4.0 EB05 3.2 · IC025 +1.6 3/3 methods agree | Not in label — unassessed | serious PRR 3.2 | no trial data cached |
| Pneumothorax | 19 | 4.1 2.6–6.4ROR 4.1 · χ² 42 / p 6e-11 | 3.8 EB05 2.6 · IC025 +1.2 3/3 methods agree | Not in label — unassessed | serious PRR 2.9 | no trial data cached |
| Urosepsis | 11 | 4.1 2.3–7.4ROR 4.1 · χ² 23 / p 1e-6 | 3.6 EB05 2.2 · IC025 +0.8 3/3 methods agree | Not in label — unassessed | serious PRR 2.9 | no trial data cached |
| Renal failure (kidney failure) | 159 | 4.1 3.5–4.7ROR 4.1 · χ² 367 / p 5e-82 | 4.0 EB05 3.5 · IC025 +1.7 3/3 methods agree | Labeled (related wording) related wording | serious PRR 2.9 | no trial data cached |
| Renal impairment | 99 | 4.0 3.3–4.9ROR 4.1 · χ² 225 / p 4e-51 | 4.0 EB05 3.4 · IC025 +1.7 3/3 methods agree | Not in label — unassessed | serious PRR 2.8 | no trial data cached |
| Transient ischaemic attack (mini-stroke) | 40 | 4.0 3.0–5.5ROR 4.1 · χ² 89 / p 3e-21 | 3.9 EB05 3.0 · IC025 +1.4 3/3 methods agree | Not in label — unassessed | serious PRR 2.8 | no trial data cached |
Trial evidence (ClinicalTrials.gov)
Most frequently reported reactions
By raw co-report count, regardless of disproportionality. Common terms here are often the illness itself or generic outcomes.
| Reaction | Reports | PRR 95% CI · ROR · χ²/p | EBGM EB05 · IC025 | Label screen | Serious-only & strata | Trial cross-check |
|---|---|---|---|---|---|---|
| Fall | 237 | 2.4 2.2–2.8ROR 2.5 · χ² 203 / p 3e-46 | 2.4 EB05 2.2 · IC025 +1.1 3/3 methods agree | Not in label — unassessed | serious PRR 1.9 | no trial data cached |
| Pneumonia (lung infection) | 235 | 2.5 2.2–2.8ROR 2.5 · χ² 211 / p 5e-48 | 2.5 EB05 2.2 · IC025 +1.1 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 1.8 | no trial data cached |
| Death | 225 | 0.9 0.8–1.0ROR 0.9 · χ² 3 / p 0.045 | 0.9 EB05 0.8 · IC025 -0.4 PRR-only: not supported by EBGM or IC | Outcome field, not a reaction | serious PRR 0.6 | no trial data cached |
| Anaemia (low red blood cells) | 193 | 3.5 3.0–4.0ROR 3.5 · χ² 338 / p 9e-76 | 3.4 EB05 3.0 · IC025 +1.5 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 2.6 | no trial data cached |
| Pain in extremity | 175 | 2.0 1.8–2.3ROR 2.1 · χ² 91 / p 6e-22 | 2.0 EB05 1.8 · IC025 +0.8 | Not in label — unassessed | serious PRR 2.0 | no trial data cached |
| Renal failure (kidney failure) | 159 | 4.1 3.5–4.7ROR 4.1 · χ² 367 / p 5e-82 | 4.0 EB05 3.5 · IC025 +1.7 3/3 methods agree | Labeled (related wording) related wording | serious PRR 2.9 | no trial data cached |
| Decreased appetite (loss of appetite) | 151 | 2.2 1.9–2.6ROR 2.3 · χ² 102 / p 2e-24 | 2.2 EB05 1.9 · IC025 +0.9 | Not in label — unassessed | serious PRR 2.0 | no trial data cached |
| Acute kidney injury (sudden kidney damage) | 149 | 3.3 2.9–3.9ROR 3.4 · χ² 245 / p 2e-55 | 3.3 EB05 2.9 · IC025 +1.5 3/3 methods agree | Not in label — unassessed | serious PRR 2.4 | no trial data cached |
| Drug interaction | 143 | 3.1 2.6–3.6ROR 3.1 · χ² 201 / p 8e-46 | 3.1 EB05 2.7 · IC025 +1.3 3/3 methods agree | Reporting / coding artifact | serious PRR 2.1 | no trial data cached |
| Chronic kidney disease | 141 | 6.3 5.4–7.4ROR 6.4 · χ² 625 / p 4e-138 | 6.2 EB05 5.4 · IC025 +2.3 3/3 methods agree | Not in label — unassessed | serious PRR 4.5 | no trial data cached |
| Gastrointestinal haemorrhage | 131 | 5.3 4.5–6.3ROR 5.4 · χ² 458 / p 6e-102 | 5.2 EB05 4.5 · IC025 +2.1 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 3.8 | no trial data cached |
| Hypotension (low blood pressure) | 126 | 2.2 1.8–2.6ROR 2.2 · χ² 77 / p 8e-19 | 2.1 EB05 1.8 · IC025 +0.8 | Labeled — boxed warning exact term | serious PRR 1.6 | no trial data cached |
| Cerebral infarction | 117 | 16.4 13.7–19.7ROR 16.7 · χ² 1,674 / p <1e-300 | 16.3 EB05 14.0 · IC025 +3.6 3/3 methods agree | Labeled (related wording) related wording | serious PRR 10.9 · 92% clinician | no trial data cached |
| Myocardial infarction (heart attack) | 112 | 2.2 1.8–2.6ROR 2.2 · χ² 71 / p 2e-17 | 2.2 EB05 1.9 · IC025 +0.8 | Labeled — boxed warning exact term | serious PRR 1.5 | no trial data cached |
| Urinary tract infection (bladder infection) | 106 | 2.1 1.8–2.6ROR 2.2 · χ² 63 / p 1e-15 | 2.1 EB05 1.8 · IC025 +0.8 | Labeled (related wording) related wording | serious PRR 1.9 | no trial data cached |
Unlabeled candidate signals
These flagged terms were not found in the FDA label text and do not match an artifact pattern. They are the pairs that would merit a structured assessment (temporality, dose-response, biological plausibility, consistency across databases, trial or cohort evidence). The screen has not done that; string-matching misses label wording, and a strong PRR can still be stimulated reporting, co-medication, or the disease itself.
- End stage renal disease — n=48, PRR 8.9
- Subarachnoid haemorrhage — n=20, PRR 6.7
- Melaena — n=42, PRR 6.5
- Disseminated intravascular coagulation — n=26, PRR 6.3
- Chronic kidney disease — n=141, PRR 6.3
- Pneumonia aspiration — n=45, PRR 6.2
- Altered state of consciousness — n=33, PRR 5.2
- Shock — n=34, PRR 5.1
- Coronary artery occlusion — n=20, PRR 5.0
- Tubulointerstitial nephritis — n=27, PRR 4.9
Want to assess one of these properly? The runbook describes the Bradford Hill / trial-evidence workflow used on the assessment page, and handoff_top1000_signals.csv lists the strongest unassessed pairs across all drugs.
Common questions
What are the most reported side effects of Cilostazol?
In FDA FAERS, the most frequently co-reported reaction terms for Cilostazol are fall, pneumonia, anaemia, pain in extremity, renal failure, decreased appetite. These are report counts, not rates: FAERS has no denominator, reporting is voluntary and uneven, and a term can be reported because of the illness being treated rather than the drug.
Does Cilostazol have an FDA boxed warning?
Yes. The current FDA label carries a boxed warning: CONTRAINDICATED IN HEART FAILURE PATIENTS Cilostazol tablets are contraindicated in patients with heart failure of any severity. Cilostazol and several of its metabolites are inhibitors of phosphodiesterase III. Seve.
Do FAERS signals prove that Cilostazol causes these side effects?
No. A disproportionality signal (PRR, ROR) means a reaction is reported more often with this drug than with others in the database. That can reflect a real effect, but also the disease being treated, stimulated reporting after news or litigation, co-medications, or how reports are coded. Causality needs temporality, dose-response, biological plausibility, consistency across data sources and, ideally, trial or cohort evidence. This page screens each term against the FDA label and ClinicalTrials.gov results; it does not establish causation.
Sources & methods
- FDA label via openFDA (set ID 15478d90-312f-014e-e063-6294a90ae838, effective 20240404; matched on
openfda.generic_name.exact:"CILOSTAZOL") - Bayesian shrinkage measures computed offline over all 1,317,300 cached pairs: BCPNN information component (IC, with Norén closed-form IC025) and MGPS empirical-Bayes geometric mean (EBGM, EB05) with a two-component gamma prior fitted by maximum marginal likelihood (α₁=0.57, β₁=0.02, α₂=1.42, β₂=0.70, w=0.17); unstratified
- FAERS pair statistics from the OpenPV build of 2026-09-14 (openFDA
count=aggregation, fieldpatient.drug.openfda.generic_name.exact, 448 reaction terms, min 3 co-reports); PRR/ROR with 95% CI, chi-square with Yates correction - Serious-only and stratified counts (serious:1, patient.patientsex, primarysource.qualification) from openFDA count queries; serious-only PRR uses the drug serious report total and the term global serious total (N_serious=11,882,979); strata shown only when n ≥ 20
- Seriousness and sex counts from openFDA
count=serious,patient.patientsex,seriousnessdeath
Page generated 2026-10-08. Label and PubChem text are retrieved automatically and may lag the current label; always check the current prescribing information. OpenPV is a beta research tool of the Open Source Medicine Foundation.