Quinine Sulfate side effects: what 3,537 FDA adverse event reports show
Drug class
Antimalarial drug
Brand names
Quinine Sulfate
Who reports
3,537 reports · 89% serious · 564 with death outcome · 61% 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.
- 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.
- 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. 327 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 |
|---|---|---|---|---|---|---|
| Thrombotic microangiopathy | 41 | 25.2 18.6–34.2ROR 25.5 · χ² 925 / p 2e-203 | 24.8 EB05 19.1 · IC025 +3.8 3/3 methods agree | Not in label — unassessed | serious PRR 16.3 · 100% clinician | no trial data cached |
| Myocardial ischaemia | 44 | 22.8 17.0–30.6ROR 23.1 · χ² 893 / p 2e-196 | 22.5 EB05 17.5 · IC025 +3.7 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 14.8 | no trial data cached |
| Coagulopathy | 62 | 22.2 17.3–28.4ROR 22.6 · χ² 1,230 / p 8e-270 | 22.0 EB05 17.8 · IC025 +3.8 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 15.0 · ♀ 92% (drug 61%) | no trial data cached |
| Haematemesis (vomiting blood) | 80 | 18.7 15.1–23.2ROR 19.1 · χ² 1,321 / p 2e-289 | 18.6 EB05 15.4 · IC025 +3.7 3/3 methods agree | Not in label — unassessed | serious PRR 12.4 · ♀ 83% (drug 61%) · 94% clinician | no trial data cached |
| Coronary artery disease | 82 | 16.0 12.9–19.8ROR 16.3 · χ² 1,134 / p 5e-249 | 15.9 EB05 13.2 · IC025 +3.5 3/3 methods agree | Not in label — unassessed | serious PRR 10.4 · ♀ 83% (drug 61%) | no trial data cached |
| Hepatic failure | 81 | 15.9 12.8–19.8ROR 16.3 · χ² 1,117 / p 3e-245 | 15.8 EB05 13.1 · IC025 +3.5 3/3 methods agree | Not in label — unassessed | serious PRR 10.3 · ♀ 89% (drug 61%) | no trial data cached |
| Cardiomegaly | 31 | 14.8 10.5–21.1ROR 15.0 · χ² 386 / p 3e-86 | 14.5 EB05 10.5 · IC025 +3.0 3/3 methods agree | Not in label — unassessed | serious PRR 9.6 | no trial data cached |
| Hypomagnesaemia | 34 | 14.6 10.4–20.4ROR 14.7 · χ² 415 / p 1e-92 | 14.2 EB05 10.5 · IC025 +3.0 3/3 methods agree | Not in label — unassessed | serious PRR 9.7 | no trial data cached |
| Atelectasis | 23 | 14.1 9.4–21.2ROR 14.2 · χ² 266 / p 4e-60 | 13.5 EB05 9.1 · IC025 +2.8 3/3 methods agree | Not in label — unassessed | serious PRR 9.2 | no trial data cached |
| Economic problem | 35 | 13.5 9.7–18.8ROR 13.6 · χ² 392 / p 2e-87 | 13.1 EB05 9.7 · IC025 +3.0 3/3 methods agree | Reporting / coding artifact | serious PRR 9.5 | no trial data cached |
| Post procedural haemorrhage | 26 | 13.2 9.0–19.4ROR 13.3 · χ² 281 / p 2e-63 | 12.7 EB05 8.8 · IC025 +2.8 3/3 methods agree | Reporting / coding artifact | serious PRR 9.6 · ♀ 100% (drug 61%) · 100% clinician | no trial data cached |
| Mitral valve incompetence | 24 | 12.6 8.4–18.8ROR 12.7 · χ² 244 / p 2e-55 | 11.9 EB05 8.1 · IC025 +2.7 3/3 methods agree | Not in label — unassessed | serious PRR 8.2 | no trial data cached |
| Fibromyalgia | 47 | 11.5 8.6–15.3ROR 11.6 · χ² 439 / p 7e-98 | 11.1 EB05 8.6 · IC025 +2.9 3/3 methods agree | Not in label — unassessed | serious PRR 9.8 · ♀ 100% (drug 61%) | no trial data cached |
| Acute hepatic failure | 26 | 11.4 7.7–16.7ROR 11.4 · χ² 235 / p 2e-53 | 10.6 EB05 7.3 · IC025 +2.6 3/3 methods agree | Not in label — unassessed | serious PRR 7.4 · ♀ 96% (drug 61%) | no trial data cached |
| Arteriosclerosis | 18 | 11.3 7.1–18.0ROR 11.4 · χ² 159 / p 8e-37 | 10.3 EB05 6.4 · IC025 +2.4 3/3 methods agree | Not in label — unassessed | serious PRR 7.6 | no trial data cached |
| Renal failure acute | 79 | 10.9 8.8–13.6ROR 11.1 · χ² 701 / p 1e-154 | 10.7 EB05 8.8 · IC025 +3.0 3/3 methods agree | Labeled (related wording) related wording | serious PRR 7.0 | no trial data cached |
| Deafness | 48 | 10.9 8.2–14.4ROR 11.0 · χ² 421 / p 9e-94 | 10.5 EB05 8.1 · IC025 +2.8 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 7.2 · 84% consumer | no trial data cached |
| Ulcer | 27 | 10.1 6.9–14.7ROR 10.1 · χ² 211 / p 4e-48 | 9.3 EB05 6.5 · IC025 +2.5 3/3 methods agree | Not in label — unassessed | serious PRR 8.2 · ♀ 100% (drug 61%) · 92% clinician | no trial data cached |
| Hiatus hernia | 21 | 9.6 6.3–14.7ROR 9.7 · χ² 153 / p 2e-35 | 8.6 EB05 5.7 · IC025 +2.3 3/3 methods agree | Not in label — unassessed | serious PRR 7.1 · ♀ 81% (drug 61%) | no trial data cached |
| Vaginal discharge | 16 | 9.5 5.8–15.4ROR 9.5 · χ² 113 / p 1e-26 | 8.1 EB05 5.1 · IC025 +2.1 3/3 methods agree | Not in label — unassessed | serious n=16 | no trial data cached |
| Blood sodium decreased | 28 | 8.8 6.1–12.8ROR 8.9 · χ² 187 / p 8e-43 | 8.1 EB05 5.7 · IC025 +2.3 3/3 methods agree | Lab value / disease marker | serious PRR 6.5 | no trial data cached |
| Blood alkaline phosphatase increased | 37 | 8.8 6.4–12.2ROR 8.9 · χ² 249 / p 2e-56 | 8.2 EB05 6.1 · IC025 +2.4 3/3 methods agree | Lab value / disease marker | serious PRR 6.1 | no trial data cached |
| Multi-organ failure | 26 | 8.8 6.0–12.9ROR 8.9 · χ² 172 / p 1e-39 | 8.0 EB05 5.6 · IC025 +2.3 3/3 methods agree | Not in label — unassessed | serious PRR 5.7 · 100% clinician | no trial data cached |
| Mood altered | 40 | 8.7 6.4–11.9ROR 8.8 · χ² 266 / p 4e-60 | 8.2 EB05 6.2 · IC025 +2.5 3/3 methods agree | Not in label — unassessed | serious PRR 10.1 · ♀ 90% (drug 61%) | no trial data cached |
| Tendon rupture (torn tendon) | 18 | 8.6 5.4–13.7ROR 8.7 · χ² 114 / p 7e-27 | 7.5 EB05 4.9 · IC025 +2.0 3/3 methods agree | Not in label — unassessed | serious PRR 6.1 | no trial data cached |
| Hepatocellular injury | 20 | 8.3 5.4–12.9ROR 8.4 · χ² 122 / p 1e-28 | 7.3 EB05 4.9 · IC025 +2.1 3/3 methods agree | Not in label — unassessed | serious PRR 5.4 · ♀ 100% (drug 61%) | no trial data cached |
| Intervertebral disc degeneration | 13 | 8.3 4.8–14.3ROR 8.3 · χ² 76 / p 1e-18 | 6.8 EB05 4.1 · IC025 +1.8 3/3 methods agree | Not in label — unassessed | serious PRR 5.7 | no trial data cached |
| Grand mal convulsion | 13 | 8.2 4.8–14.2ROR 8.3 · χ² 76 / p 2e-18 | 6.8 EB05 4.1 · IC025 +1.8 3/3 methods agree | Not in label — unassessed | serious PRR 5.4 | no trial data cached |
| Gastric ulcer | 26 | 8.1 5.5–11.9ROR 8.2 · χ² 155 / p 7e-36 | 7.3 EB05 5.2 · IC025 +2.2 3/3 methods agree | Not in label — unassessed | serious PRR 5.6 | no trial data cached |
| Haematocrit decreased | 27 | 8.0 5.5–11.7ROR 8.1 · χ² 159 / p 9e-37 | 7.3 EB05 5.2 · IC025 +2.2 3/3 methods agree | Lab value / disease marker | serious PRR 5.9 | no trial data cached |
| Renal failure (kidney failure) | 179 | 7.9 6.9–9.2ROR 8.3 · χ² 1,085 / p 4e-238 | 7.8 EB05 6.9 · IC025 +2.7 3/3 methods agree | Labeled — boxed warning synonym match | serious PRR 5.2 · ♀ 81% (drug 61%) | no trial data cached |
| Hyperlipidaemia | 16 | 7.9 4.9–12.9ROR 8.0 · χ² 90 / p 1e-21 | 6.7 EB05 4.3 · IC025 +1.9 3/3 methods agree | Not in label — unassessed | serious PRR 5.7 | no trial data cached |
| International normalised ratio increased | 38 | 7.8 5.7–10.7ROR 7.9 · χ² 220 / p 5e-50 | 7.3 EB05 5.5 · IC025 +2.3 3/3 methods agree | Labeled (related wording) related wording | serious PRR 5.4 | no trial data cached |
| Osteopenia | 20 | 7.8 5.0–12.0ROR 7.8 · χ² 111 / p 2e-26 | 6.8 EB05 4.6 · IC025 +2.0 3/3 methods agree | Not in label — unassessed | serious PRR 6.0 | no trial data cached |
| Anorexia | 17 | 7.7 4.8–12.4ROR 7.8 · χ² 93 / p 3e-22 | 6.6 EB05 4.3 · IC025 +1.9 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 5.0 | no trial data cached |
| Liver function test abnormal | 38 | 7.7 5.6–10.6ROR 7.8 · χ² 215 / p 5e-49 | 7.2 EB05 5.4 · IC025 +2.3 3/3 methods agree | Reporting / coding artifact | serious PRR 5.9 | no trial data cached |
| Ventricular tachycardia | 21 | 7.5 4.9–11.5ROR 7.6 · χ² 112 / p 2e-26 | 6.6 EB05 4.5 · IC025 +2.0 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 4.9 | no trial data cached |
| Restless legs syndrome | 23 | 7.5 5.0–11.3ROR 7.5 · χ² 123 / p 7e-29 | 6.7 EB05 4.6 · IC025 +2.0 3/3 methods agree | Not in label — unassessed | serious PRR 7.6 | no trial data cached |
| Hyperkalaemia (high potassium) | 44 | 7.5 5.6–10.0ROR 7.6 · χ² 241 / p 1e-54 | 7.0 EB05 5.4 · IC025 +2.3 3/3 methods agree | Not in label — unassessed | serious PRR 4.8 | no trial data cached |
| Fear | 34 | 7.4 5.3–10.4ROR 7.5 · χ² 183 / p 5e-42 | 6.9 EB05 5.1 · IC025 +2.2 3/3 methods agree | Not in label — unassessed | serious PRR 6.6 · ♀ 39% (drug 61%) | 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 |
|---|---|---|---|---|---|---|
| Renal failure (kidney failure) | 179 | 7.9 6.9–9.2ROR 8.3 · χ² 1,085 / p 4e-238 | 7.8 EB05 6.9 · IC025 +2.7 3/3 methods agree | Labeled — boxed warning synonym match | serious PRR 5.2 · ♀ 81% (drug 61%) | no trial data cached |
| Fall | 170 | 3.0 2.6–3.5ROR 3.1 · χ² 233 / p 6e-53 | 3.0 EB05 2.7 · IC025 +1.3 3/3 methods agree | Not in label — unassessed | serious PRR 2.3 | no trial data cached |
| Muscle spasms | 156 | 5.0 4.3–5.9ROR 5.2 · χ² 505 / p 3e-112 | 5.0 EB05 4.3 · IC025 +2.0 3/3 methods agree | Not in label — unassessed | serious PRR 5.4 | no trial data cached |
| Chest pain | 145 | 4.6 4.0–5.4ROR 4.8 · χ² 413 / p 4e-92 | 4.6 EB05 4.0 · IC025 +1.9 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 3.9 | no trial data cached |
| Thrombocytopenia (low platelets) | 136 | 7.2 6.1–8.5ROR 7.5 · χ² 728 / p 1e-160 | 7.1 EB05 6.1 · IC025 +2.5 3/3 methods agree | Labeled — boxed warning exact term | serious PRR 4.8 | no trial data cached |
| Pain in extremity | 130 | 2.6 2.2–3.1ROR 2.7 · χ² 129 / p 3e-30 | 2.6 EB05 2.2 · IC025 +1.1 3/3 methods agree | Not in label — unassessed | serious PRR 2.7 | no trial data cached |
| Confusional state (confusion) | 125 | 4.6 3.9–5.4ROR 4.7 · χ² 349 / p 4e-78 | 4.5 EB05 3.9 · IC025 +1.9 3/3 methods agree | Labeled (related wording) related wording | serious PRR 3.7 | no trial data cached |
| Acute kidney injury (sudden kidney damage) | 121 | 4.7 4.0–5.6ROR 4.8 · χ² 353 / p 6e-79 | 4.6 EB05 4.0 · IC025 +1.9 3/3 methods agree | Labeled — boxed warning synonym match | serious PRR 3.1 | no trial data cached |
| Oedema peripheral (swelling of legs/feet) | 112 | 5.4 4.5–6.5ROR 5.6 · χ² 403 / p 8e-90 | 5.3 EB05 4.5 · IC025 +2.1 3/3 methods agree | Labeled (related wording) related wording | serious PRR 4.4 | no trial data cached |
| Drug interaction | 106 | 4.0 3.3–4.8ROR 4.1 · χ² 233 / p 5e-53 | 3.9 EB05 3.3 · IC025 +1.6 3/3 methods agree | Reporting / coding artifact | serious PRR 2.8 | no trial data cached |
| Myocardial infarction (heart attack) | 102 | 3.4 2.8–4.2ROR 3.5 · χ² 176 / p 2e-40 | 3.4 EB05 2.9 · IC025 +1.4 3/3 methods agree | Not in label — unassessed | serious PRR 2.2 | no trial data cached |
| Toxicity to various agents | 102 | 3.6 3.0–4.4ROR 3.7 · χ² 191 / p 1e-43 | 3.6 EB05 3.0 · IC025 +1.5 3/3 methods agree | Not in label — unassessed | serious PRR 2.4 | no trial data cached |
| Dehydration | 97 | 4.3 3.5–5.2ROR 4.4 · χ² 245 / p 2e-55 | 4.2 EB05 3.6 · IC025 +1.7 3/3 methods agree | Not in label — unassessed | serious PRR 3.2 | no trial data cached |
| Urinary tract infection (bladder infection) | 94 | 3.3 2.7–4.0ROR 3.3 · χ² 148 / p 3e-34 | 3.2 EB05 2.7 · IC025 +1.4 3/3 methods agree | Not in label — unassessed | serious PRR 2.7 · ♀ 82% (drug 61%) | no trial data cached |
| Atrial fibrillation | 92 | 5.6 4.6–6.8ROR 5.7 · χ² 344 / p 4e-77 | 5.4 EB05 4.6 · IC025 +2.1 3/3 methods agree | Labeled — boxed warning exact term | serious PRR 3.7 | 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.
- Thrombotic microangiopathy — n=41, PRR 25.2
- Haematemesis — n=80, PRR 18.7
- Coronary artery disease — n=82, PRR 16.0
- Hepatic failure — n=81, PRR 15.9
- Cardiomegaly — n=31, PRR 14.8
- Hypomagnesaemia — n=34, PRR 14.6
- Atelectasis — n=23, PRR 14.1
- Mitral valve incompetence — n=24, PRR 12.6
- Fibromyalgia — n=47, PRR 11.5
- Acute hepatic failure — n=26, PRR 11.4
✓ 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 renal failure, fall, muscle spasms, chest pain, thrombocytopenia, pain in extremity. 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, 367 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.