Quinine side effects: what 8,527 FDA adverse event reports show
Drug class
Antimalarial drug
Brand names
Quinine Sulfate
Who reports
8,527 reports · 91% serious · 1,700 with death outcome · 58% female
Used for
Quinine sulfate is an antimalarial drug indicated only for treatment of uncomplicated Plasmodium falciparum malaria. Quinine sulfate has been shown to be effective in geographical regions where resistance to chloroquine has been documented . Limitations of Use: Quinine sulfate capsules are not approved for: Treatment of severe or complicated P. falciparum malaria. Prevention of malaria.
What it is
Quinine sulfate is a cinchona alkaloid chemically described as cinchonan-9-ol, 6’-methoxy-, (8α, 9R)-, sulfate (2:1) (salt), dihydrate with a molecular formula of (C 20 H 24 N 2 O 2 )2•H 2 SO 4 •2H 2 O and a molecular weight of 782.96.
Boxed warning
HEMATOLOGIC REACTIONS Quinine sulfate use for the treatment or prevention of nocturnal leg cramps may result in serious and life-threatening hematologic reactions, including thrombocytopenia and hemolytic uremic syndrome/thrombotic thrombocytopenic purpura (HUS/TTP). Chronic renal impairment associated with the development of TTP has been reported.
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.
- Likely indication confounding The term appears in the label's indications: reports probably describe the disease being treated (or its progression), not a drug effect. Classic confounding by indication.
- 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.
- Lab value / disease marker A laboratory result, investigation or disease-activity marker (antibody positive, CRP abnormal, swollen joint count) not described in the label. These usually mirror the monitored disease or testing protocol rather than a drug effect; not screened further.
- 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. 1,020 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 |
|---|---|---|---|---|---|---|
| Cinchonism | 19 | 3,545.7 1,751.7–7,177.1ROR 3,553.6 · χ² 25,931 / p <1e-300 | 585.8 EB05 396.4 · IC025 +4.5 3/3 methods agree | Labeled adverse reaction exact term | serious n=19 | no trial data cached |
| Purpura senile | 10 | 224.6 117.6–429.2ROR 224.9 · χ² 1,838 / p <1e-300 | 148.2 EB05 86.0 · IC025 +3.2 3/3 methods agree | Not in label — unassessed | serious n=10 | no trial data cached |
| Hepatic ischaemia | 26 | 223.7 149.8–334.1ROR 224.4 · χ² 5,075 / p <1e-300 | 178.2 EB05 127.8 · IC025 +4.7 3/3 methods agree | Not in label — unassessed | serious n=26 · ♀ 100% (drug 58%) · 100% clinician | no trial data cached |
| Plasmodium falciparum infection | 10 | 214.7 112.5–409.7ROR 214.9 · χ² 1,763 / p <1e-300 | 143.8 EB05 83.5 · IC025 +3.2 3/3 methods agree | Likely indication confounding shares a disease stem with the indications wording | serious n=10 | no trial data cached |
| Visual pathway disorder | 10 | 161.7 85.3–306.7ROR 161.9 · χ² 1,351 / p 6e-296 | 118.1 EB05 68.6 · IC025 +3.1 3/3 methods agree | Not in label — unassessed | serious n=10 | no trial data cached |
| Multiple drug therapy | 43 | 161.5 118.7–219.7ROR 162.3 · χ² 6,281 / p <1e-300 | 142.0 EB05 109.8 · IC025 +5.3 3/3 methods agree | Reporting / coding artifact | serious n=43 · ♀ 100% (drug 58%) · 93% clinician | no trial data cached |
| Creatinine renal clearance increased | 44 | 152.9 112.9–207.2ROR 153.7 · χ² 6,105 / p <1e-300 | 135.6 EB05 105.2 · IC025 +5.3 3/3 methods agree | Lab value / disease marker | serious n=44 · ♀ 100% (drug 58%) · 93% clinician | no trial data cached |
| Somatic symptom disorder | 54 | 129.3 98.4–169.9ROR 130.1 · χ² 6,407 / p <1e-300 | 117.8 EB05 93.7 · IC025 +5.4 3/3 methods agree | Not in label — unassessed | serious n=54 · ♀ 100% (drug 58%) | no trial data cached |
| Agitated depression | 14 | 125.3 73.3–214.4ROR 125.5 · χ² 1,526 / p <1e-300 | 102.9 EB05 65.1 · IC025 +3.7 3/3 methods agree | Not in label — unassessed | serious n=14 | no trial data cached |
| Atrioventricular dissociation | 10 | 120.1 63.7–226.5ROR 120.2 · χ² 1,015 / p 6e-223 | 94.4 EB05 54.8 · IC025 +3.1 3/3 methods agree | Not in label — unassessed | serious n=10 | no trial data cached |
| Labile blood pressure | 54 | 117.1 89.2–153.7ROR 117.8 · χ² 5,818 / p <1e-300 | 107.6 EB05 85.6 · IC025 +5.3 3/3 methods agree | Not in label — unassessed | serious n=54 · ♀ 100% (drug 58%) · 94% clinician | no trial data cached |
| Tarsal tunnel syndrome | 10 | 116.6 61.9–219.9ROR 116.8 · χ² 986 / p 9e-217 | 92.3 EB05 53.6 · IC025 +3.1 3/3 methods agree | Not in label — unassessed | serious n=10 | no trial data cached |
| Babesiosis | 12 | 109.9 61.6–195.8ROR 110.0 · χ² 1,136 / p 2e-249 | 90.5 EB05 55.1 · IC025 +3.4 3/3 methods agree | Not in label — unassessed | serious n=12 | no trial data cached |
| Fear of eating | 12 | 100.4 56.4–178.8ROR 100.5 · χ² 1,040 / p 1e-228 | 84.0 EB05 51.2 · IC025 +3.3 3/3 methods agree | Not in label — unassessed | serious n=12 | no trial data cached |
| Sedation complication | 96 | 98.2 80.2–120.3ROR 99.3 · χ² 8,783 / p <1e-300 | 92.7 EB05 78.2 · IC025 +5.7 3/3 methods agree | Reporting / coding artifact | serious n=96 · ♀ 85% (drug 58%) · 93% clinician | no trial data cached |
| Retinal vascular disorder | 22 | 97.8 63.9–149.6ROR 98.0 · χ² 1,933 / p <1e-300 | 87.1 EB05 60.6 · IC025 +4.2 3/3 methods agree | Not in label — unassessed | serious n=22 | no trial data cached |
| Retinogram abnormal | 10 | 94.8 50.4–178.2ROR 94.9 · χ² 805 / p 2e-177 | 78.1 EB05 45.4 · IC025 +3.0 3/3 methods agree | Not in label — unassessed | serious n=10 | no trial data cached |
| Sacroiliitis | 55 | 73.4 56.2–95.9ROR 73.9 · χ² 3,745 / p <1e-300 | 69.7 EB05 55.5 · IC025 +5.0 3/3 methods agree | Not in label — unassessed | serious n=54 · ♀ 100% (drug 58%) | no trial data cached |
| Toxic neuropathy | 10 | 64.4 34.4–120.5ROR 64.4 · χ² 547 / p 2e-121 | 56.3 EB05 32.7 · IC025 +2.9 3/3 methods agree | Not in label — unassessed | serious n=10 | no trial data cached |
| Microangiopathic haemolytic anaemia | 19 | 61.7 39.2–97.2ROR 61.8 · χ² 1,048 / p 3e-230 | 56.9 EB05 38.5 · IC025 +3.8 3/3 methods agree | Not in label — unassessed | serious n=19 | no trial data cached |
| Retinal toxicity | 23 | 56.8 37.6–85.9ROR 57.0 · χ² 1,179 / p 1e-258 | 53.2 EB05 37.4 · IC025 +4.0 3/3 methods agree | Not in label — unassessed | serious n=23 · 100% clinician | no trial data cached |
| Hepatorenal syndrome | 38 | 56.3 40.9–77.7ROR 56.6 · χ² 1,965 / p <1e-300 | 53.7 EB05 40.8 · IC025 +4.5 3/3 methods agree | Not in label — unassessed | serious n=38 · ♀ 89% (drug 58%) · 94% clinician | no trial data cached |
| Oral cavity fistula | 11 | 55.8 30.7–101.5ROR 55.9 · χ² 527 / p 8e-117 | 50.1 EB05 29.9 · IC025 +3.0 3/3 methods agree | Not in label — unassessed | serious n=11 | no trial data cached |
| Creatinine renal clearance decreased | 77 | 47.9 38.3–60.0ROR 48.3 · χ² 3,422 / p <1e-300 | 46.5 EB05 38.4 · IC025 +4.8 3/3 methods agree | Lab value / disease marker | serious n=77 · ♀ 100% (drug 58%) · 91% clinician | no trial data cached |
| Malaria | 13 | 45.9 26.5–79.4ROR 46.0 · χ² 517 / p 8e-115 | 42.5 EB05 26.4 · IC025 +3.2 3/3 methods agree | Likely indication confounding term in indications; also in warnings | serious n=11 | no trial data cached |
| Alveolar proteinosis | 10 | 42.7 22.9–79.8ROR 42.8 · χ² 360 / p 1e-80 | 39.1 EB05 22.7 · IC025 +2.8 3/3 methods agree | Not in label — unassessed | serious n=10 | no trial data cached |
| Neoplasm skin | 23 | 36.9 24.5–55.7ROR 37.0 · χ² 756 / p 8e-167 | 35.4 EB05 24.8 · IC025 +3.7 3/3 methods agree | Not in label — unassessed | serious n=23 · ♀ 100% (drug 58%) | no trial data cached |
| Thrombocytopenic purpura | 20 | 36.1 23.2–56.1ROR 36.2 · χ² 638 / p 4e-141 | 34.5 EB05 23.6 · IC025 +3.5 3/3 methods agree | Labeled — boxed warning exact term | serious n=20 · ♀ 80% (drug 58%) | no trial data cached |
| Resorption bone increased | 11 | 33.4 18.5–60.6ROR 33.5 · χ² 310 / p 1e-69 | 31.4 EB05 18.6 · IC025 +2.8 3/3 methods agree | Not in label — unassessed | serious n=11 | no trial data cached |
| Renal function test abnormal | 61 | 33.1 25.7–42.6ROR 33.3 · χ² 1,842 / p <1e-300 | 32.4 EB05 26.1 · IC025 +4.3 3/3 methods agree | Reporting / coding artifact | serious n=61 · ♀ 100% (drug 58%) | no trial data cached |
| Exposure via ingestion | 31 | 30.2 21.2–43.0ROR 30.3 · χ² 837 / p 3e-184 | 29.4 EB05 21.7 · IC025 +3.8 3/3 methods agree | Reporting / coding artifact | serious n=31 · ♀ 23% (drug 58%) · 100% clinician | no trial data cached |
| Idiopathic thrombocytopenic purpura | 19 | 29.5 18.8–46.3ROR 29.6 · χ² 489 / p 1e-108 | 28.4 EB05 19.2 · IC025 +3.3 3/3 methods agree | Labeled adverse reaction exact term | serious n=19 | no trial data cached |
| Nephrogenic systemic fibrosis | 36 | 29.3 21.1–40.6ROR 29.4 · χ² 943 / p 2e-207 | 28.5 EB05 21.5 · IC025 +3.8 3/3 methods agree | Not in label — unassessed | serious n=36 | no trial data cached |
| Vestibular disorder | 14 | 28.4 16.8–48.1ROR 28.4 · χ² 339 / p 5e-76 | 27.1 EB05 17.1 · IC025 +3.0 3/3 methods agree | Not in label — unassessed | serious n=14 | no trial data cached |
| Nail infection | 16 | 27.8 17.0–45.4ROR 27.8 · χ² 382 / p 2e-85 | 26.7 EB05 17.4 · IC025 +3.1 3/3 methods agree | Not in label — unassessed | serious n=16 | no trial data cached |
| Exposed bone in jaw | 24 | 27.2 18.2–40.7ROR 27.3 · χ² 574 / p 4e-127 | 26.4 EB05 18.7 · IC025 +3.5 3/3 methods agree | Not in label — unassessed | serious n=24 · ♀ 82% (drug 58%) | no trial data cached |
| Skin hypertrophy | 28 | 24.8 17.1–36.0ROR 24.9 · χ² 610 / p 5e-135 | 24.2 EB05 17.6 · IC025 +3.5 3/3 methods agree | Not in label — unassessed | serious n=28 | no trial data cached |
| Thrombotic microangiopathy | 96 | 24.6 20.1–30.1ROR 24.9 · χ² 2,130 / p <1e-300 | 24.3 EB05 20.5 · IC025 +4.1 3/3 methods agree | Not in label — unassessed | serious PRR 15.5 · ♀ 100% (drug 58%) · 100% clinician | no trial data cached |
| Vascular injury | 14 | 24.3 14.3–41.1ROR 24.3 · χ² 287 / p 1e-64 | 23.3 EB05 14.6 · IC025 +2.8 3/3 methods agree | Not in label — unassessed | serious n=14 | no trial data cached |
| Skin induration | 20 | 24.0 15.5–37.3ROR 24.1 · χ² 415 / p 2e-92 | 23.3 EB05 15.9 · IC025 +3.2 3/3 methods agree | Not in label — unassessed | serious n=20 · ♀ 35% (drug 58%) | 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 |
|---|---|---|---|---|---|---|
| Drug abuse | 727 | 21.6 20.1–23.1ROR 23.5 · χ² 14,161 / p <1e-300 | 21.4 EB05 20.1 · IC025 +4.3 3/3 methods agree | Reporting / coding artifact | serious PRR 13.6 · ♀ 29% (drug 58%) · 99% clinician | no trial data cached |
| Toxicity to various agents | 506 | 7.4 6.8–8.1ROR 7.8 · χ² 2,826 / p <1e-300 | 7.4 EB05 6.8 · IC025 +2.7 3/3 methods agree | Not in label — unassessed | serious PRR 4.8 · 94% clinician | no trial data cached |
| Dyspnoea (shortness of breath) | 486 | 2.1 1.9–2.3ROR 2.2 · χ² 292 / p 9e-66 | 2.1 EB05 2.0 · IC025 +0.9 | Labeled adverse reaction exact term | serious PRR 1.7 | no trial data cached |
| Fall | 454 | 3.4 3.1–3.7ROR 3.5 · χ² 762 / p 5e-168 | 3.3 EB05 3.1 · IC025 +1.6 3/3 methods agree | Not in label — unassessed | serious PRR 2.5 | no trial data cached |
| Nausea | 450 | 1.4 1.3–1.5ROR 1.4 · χ² 54 / p 1e-13 | 1.4 EB05 1.3 · IC025 +0.3 | Labeled adverse reaction exact term | serious PRR 1.5 | no trial data cached |
| Pain | 429 | 1.7 1.6–1.9ROR 1.8 · χ² 131 / p 1e-30 | 1.7 EB05 1.6 · IC025 +0.6 | Labeled adverse reaction exact term | serious PRR 1.6 | no trial data cached |
| Diarrhoea (diarrhea) | 376 | 1.4 1.3–1.6ROR 1.5 · χ² 51 / p 4e-13 | 1.4 EB05 1.3 · IC025 +0.4 | Labeled adverse reaction exact term | serious PRR 1.5 | no trial data cached |
| Vomiting | 368 | 1.9 1.7–2.1ROR 2.0 · χ² 168 / p 1e-38 | 1.9 EB05 1.8 · IC025 +0.8 | Labeled adverse reaction exact term | serious PRR 1.7 | no trial data cached |
| Dizziness | 341 | 1.7 1.5–1.9ROR 1.7 · χ² 97 / p 4e-23 | 1.7 EB05 1.5 · IC025 +0.6 | Labeled adverse reaction exact term | serious PRR 1.6 | no trial data cached |
| Muscle spasms | 311 | 4.2 3.7–4.7ROR 4.3 · χ² 752 / p 6e-166 | 4.1 EB05 3.8 · IC025 +1.9 3/3 methods agree | Not in label — unassessed | serious PRR 4.2 | no trial data cached |
| Hypotension (low blood pressure) | 304 | 3.7 3.3–4.2ROR 3.8 · χ² 612 / p 2e-135 | 3.7 EB05 3.4 · IC025 +1.7 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 2.7 | no trial data cached |
| Drug interaction | 301 | 4.7 4.2–5.2ROR 4.8 · χ² 870 / p 2e-191 | 4.6 EB05 4.2 · IC025 +2.0 3/3 methods agree | Reporting / coding artifact | serious PRR 3.3 | no trial data cached |
| Fatigue (tiredness) | 297 | 0.9 0.8–1.1ROR 0.9 · χ² 1 / p 0.146 | 0.9 EB05 0.9 · IC025 -0.3 PRR-only: not supported by EBGM or IC | Labeled (related wording) related wording | serious PRR 1.0 | no trial data cached |
| Headache | 294 | 1.2 1.0–1.3ROR 1.2 · χ² 6 / p 0.007 | 1.2 EB05 1.0 · IC025 +0.0 | Labeled adverse reaction exact term | serious PRR 1.3 | no trial data cached |
| Drug ineffective (drug did not work) | 272 | 0.5 0.5–0.6ROR 0.5 · χ² 138 / p 4e-32 | 0.5 EB05 0.5 · IC025 -1.2 PRR-only: not supported by EBGM or IC | Reporting / coding artifact | serious PRR 0.7 | 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.
- Hepatic ischaemia — n=26, PRR 223.7
- Somatic symptom disorder — n=54, PRR 129.3
- Labile blood pressure — n=54, PRR 117.1
- Retinal vascular disorder — n=22, PRR 97.8
- Sacroiliitis — n=55, PRR 73.4
- Retinal toxicity — n=23, PRR 56.8
- Hepatorenal syndrome — n=38, PRR 56.3
- Neoplasm skin — n=23, PRR 36.9
- Nephrogenic systemic fibrosis — n=36, PRR 29.3
- Exposed bone in jaw — n=24, PRR 27.2
✓ A hand-written Bradford Hill causality assessment exists for this drug: Quinine ↔ Thrombocytopenia.
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 Quinine?
In FDA FAERS, the most frequently co-reported reaction terms for Quinine are toxicity to various agents, dyspnoea, fall, nausea, pain, diarrhoea. 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 Quinine have an FDA boxed warning?
Yes. The current FDA label carries a boxed warning: HEMATOLOGIC REACTIONS Quinine sulfate use for the treatment or prevention of nocturnal leg cramps may result in serious and life-threatening hematologic reactions, including thrombocytopenia and hemolytic uremic syndrome/thrombotic thrombocytopenic purpura (HUS/TTP). Chronic renal impairment associated with the development of TTP has been reported.
Do FAERS signals prove that Quinine 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 f567d5c7-ea5d-49a7-a035-b47208135f73, effective 20241209; matched on
openfda.generic_name.exact:"QUININE") - 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, 1,060 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.