Drug · FAERS side-effect profile with label screen

Mefloquine side effects: what 156 FDA adverse event reports show

Mefloquine Hydrochloride · 6 reaction terms · 60 drug–reaction co-reports · data 2026-09-14

Drug class

Not stated in label

Label matched

Mefloquine Hydrochloride (Mefloquine Hydrochloride)

closest FDA label found for this product string; brand list suppressed because the label is a related product, not an exact match

Who reports

156 reports · 88% serious · 14 with death outcome · 53% female

openFDA FAERS counts, all years, deduplication not applied

Used for

Treatment of Acute Malaria Infections Mefloquine hydrochloride tablets are indicated for the treatment of mild to moderate acute malaria caused by mefloquine-susceptible strains of P. falciparum (both chloroquine-susceptible and resistant strains) or by Plasmodium vivax. There are insufficient clinical data to document the effect of mefloquine in malaria caused by P. ovale or P. malariae.

FDA label, Indications and Usage

What it is

DESCRIPTION Mefloquine hydrochloride tablets, USP are an antimalarial agent available as 250 mg tablets of mefloquine hydrochloride (equivalent to 228 mg of the free base) for oral administration.

FDA label, Description section

Boxed warning

Mefloquine may cause neuropsychiatric adverse reactions that can persist after mefloquine has been discontinued. Mefloquine should not be prescribed for prophylaxis in patients with major psychiatric disorders. Durin.

FDA label

How to read this page. FAERS is a spontaneous-reporting system: counts are not incidence rates and a signal is not proof of causation. Each reaction below is run through an automated screen — is the term in the FDA label (known), in the indications (the disease being treated), an administrative/coding term, or none of these (unlabeled)? That screen is mechanical text matching, not a causality assessment. The 30 hand-written Bradford Hill assessments are on the causality assessment page. Not medical advice.

Causality screen of the 6 strongest signals

Labeled — boxed warning 1Labeled adverse reaction 2Not in label — unassessed 3

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.
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. 0 further terms are in the interactive explorer. Reaction links open the term's cross-drug page.

Show: hide coding/lab/outcome terms hide indication terms unlabeled only hide PRR-only

Reaction	Reports	PRR 95% CI · ROR · χ²/p	EBGM EB05 · IC025	Label screen	Serious-only & strata	Trial cross-check
Personality change	6	86.3 39.4–189.2ROR 89.7 · χ² 424 / p 2e-94	68.3 EB05 33.6 · IC025 +2.1 3/3 methods agree	Not in label — unassessed	serious PRR 76.0	no trial data cached
Paranoia	11	85.4 48.3–151.0ROR 91.8 · χ² 835 / p 6e-184	74.7 EB05 44.5 · IC025 +3.2 3/3 methods agree	Labeled — boxed warning exact term	serious PRR 63.9	no trial data cached
Abnormal dreams	14	67.7 41.1–111.6ROR 74.3 · χ² 856 / p 2e-188	62.2 EB05 39.4 · IC025 +3.5 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 83.7	no trial data cached
Lymphopenia	6	57.3 26.2–125.7ROR 59.6 · χ² 278 / p 9e-63	48.9 EB05 24.0 · IC025 +2.0 3/3 methods agree	Not in label — unassessed	serious PRR 40.6	no trial data cached
Nightmare	14	54.2 32.9–89.3ROR 59.4 · χ² 679 / p 5e-150	50.6 EB05 32.1 · IC025 +3.4 3/3 methods agree	Not in label — unassessed	serious PRR 43.1	no trial data cached
Mood swings	9	37.9 20.1–71.5ROR 40.2 · χ² 288 / p 6e-65	35.3 EB05 19.8 · IC025 +2.5 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 43.6	no trial data cached

Trial evidence (ClinicalTrials.gov)

Trial cross-check not yet run for this drug (ClinicalTrials.gov pull covers the 800 most-reported drugs first).

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
Nightmare	14	54.2 32.9–89.3ROR 59.4 · χ² 679 / p 5e-150	50.6 EB05 32.1 · IC025 +3.4 3/3 methods agree	Not in label — unassessed	serious PRR 43.1	no trial data cached
Abnormal dreams	14	67.7 41.1–111.6ROR 74.3 · χ² 856 / p 2e-188	62.2 EB05 39.4 · IC025 +3.5 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 83.7	no trial data cached
Paranoia	11	85.4 48.3–151.0ROR 91.8 · χ² 835 / p 6e-184	74.7 EB05 44.5 · IC025 +3.2 3/3 methods agree	Labeled — boxed warning exact term	serious PRR 63.9	no trial data cached
Mood swings	9	37.9 20.1–71.5ROR 40.2 · χ² 288 / p 6e-65	35.3 EB05 19.8 · IC025 +2.5 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 43.6	no trial data cached
Lymphopenia	6	57.3 26.2–125.7ROR 59.6 · χ² 278 / p 9e-63	48.9 EB05 24.0 · IC025 +2.0 3/3 methods agree	Not in label — unassessed	serious PRR 40.6	no trial data cached
Personality change	6	86.3 39.4–189.2ROR 89.7 · χ² 424 / p 2e-94	68.3 EB05 33.6 · IC025 +2.1 3/3 methods agree	Not in label — unassessed	serious PRR 76.0	no trial data cached

Unlabeled candidate signals

Every screened signal with n ≥ 20 was either labeled, an indication term, or an artifact pattern — no unlabeled candidate stood out in the top signals.

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 Mefloquine?

In FDA FAERS, the most frequently co-reported reaction terms for Mefloquine are nightmare, abnormal dreams, paranoia, mood swings, lymphopenia, personality change. 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 Mefloquine have an FDA boxed warning?

Yes. The current FDA label carries a boxed warning: Mefloquine may cause neuropsychiatric adverse reactions that can persist after mefloquine has been discontinued. Mefloquine should not be prescribed for prophylaxis in patients with major psychiatric disorders. Durin.

Do FAERS signals prove that Mefloquine 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 09716a24-d7da-42b2-af29-c03a1b6670bd, effective 20250926; matched on openfda.generic_name.exact:"MEFLOQUINE HYDROCHLORIDE")
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, field patient.drug.openfda.generic_name.exact, 6 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.