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Mefloquine Side Effects

Medically reviewed by Drugs.com. Last updated on Feb 23, 2022.

For the Consumer

Applies to mefloquine: oral tablets

Side effects include:

GI effects (nausea, vomiting, loose stools or diarrhea, abdominal pain); CNS effects (dizziness, vertigo); neuropsychiatric events (headache, somnolence, sleep disorders); rash; pruritus.

For Healthcare Professionals

Applies to mefloquine: oral tablet

General

At the doses used for treatment of acute malaria infections, the side effects possibly associated with this drug could not be distinguished from the side effects usually associated with the disease. The most common side effects reported during treatment included dizziness, myalgia, nausea, fever, headache, vomiting, chills, diarrhea, skin rash, abdominal pain, fatigue, loss of appetite, and tinnitus.

The most common side effects reported during malaria prophylaxis included nausea, vomiting, and dizziness.

Due to the long half-life of this drug, side effects have occurred and persisted up to several weeks after drug discontinuation.[Ref]

Psychiatric

Very common (10% or more): Abnormal dreams/strange or vivid dreams (13.7%), insomnia (13.5%)

Common (1% to 10%): Depression, anxiety

Frequency not reported: Emotional problems, transient emotional disturbances, behavioral changes, mania, nightmares, delusions, tension, anger, organic psychosis, dysphoria

Postmarketing reports: Anxiety, depression, mood swings, panic attacks, confusion/confusional state, hallucinations, aggression, agitation, restlessness, psychotic/paranoid reactions, suicidal ideation, suicide, attempted suicide, self-endangering behavior, bipolar disorder, psychotic disorder (including delusional disorder, depersonalization, mania, schizophrenia/schizophreniform disorder), paranoia, disturbance in attention[Ref]

Gastrointestinal

Common (1% to 10%): Nausea, diarrhea, abdominal pain, mouth ulcers, vomiting

Postmarketing reports: Nausea, vomiting, abdominal pain, loose stools/diarrhea, dyspepsia, pancreatitis[Ref]

Nervous system

Encephalopathy of unknown etiology was reported during prophylactic use; however, the relationship to drug administration could not be established.[Ref]

Common (1% to 10%): Dizziness, vertigo, headache

Frequency not reported: Syncope, encephalopathy of unknown etiology, tinnitus, seizures, myoclonus

Postmarketing reports: Dizziness, vertigo, loss of balance/balance disorder, neuropsychiatric events (e.g., headache, somnolence), peripheral sensory and motor neuropathies (including paresthesia, tremor, ataxia), convulsions, agitation, restlessness, memory impairment, encephalopathy, vestibular disorders (including tinnitus, hearing impairment), cranial nerve paralysis, amnesia (some lasted more than 3 months), speech disorder, gait disturbance, partial deafness (sometimes prolonged), hyperacusis[Ref]

Dermatologic

Common (1% to 10%): Itching/pruritus

Frequency not reported: Skin rash, hair loss, telogen effluvium, cutaneous vasculitis

Postmarketing reports: Rash, exanthema, erythema, urticaria, pruritus, alopecia/hair loss, hyperhidrosis, erythema multiforme, Stevens-Johnson syndrome[Ref]

Ocular

Common (1% to 10%): Visual difficulties

Postmarketing reports: Visual impairment, blurred vision, cataracts, retinal disorders, optic neuropathy[Ref]

Cardiovascular

Frequency not reported: Extrasystoles, cardiopulmonary arrest, bradycardia, transitory and clinically silent ECG alterations (including sinus bradycardia, sinus arrhythmia, first degree atrioventricular block, prolongation of the QTc interval, abnormal T waves), atrial flutter

Postmarketing reports: Circulatory disturbances (hypotension, hypertension, flushing, syncope), chest pain, tachycardia, palpitation, bradycardia, irregular heart rate, extrasystoles, atrioventricular block, other transient cardiac conduction alterations[Ref]

Cardiopulmonary arrest was reported in 1 patient after a single prophylactic dose while concomitantly using propranolol.[Ref]

Hematologic

Frequency not reported: Decreased hematocrit, anemia, isolated thrombocytopenia, hemolytic anemia, thrombotic thrombocytopenic purpura

Postmarketing reports: Agranulocytosis, aplastic anemia, leukopenia, leukocytosis, thrombocytopenia[Ref]

A 56-year-old male experienced thrombotic thrombocytopenic purpura (TTP) coincident with use of this drug. A week before admission, the patient developed weakness, followed some days later by anorexia, myalgia, and lethargy, and, finally, by fever, confusion, and blurred vision. A central venous catheter was placed in the right jugular vein and 2 plasmapheresis sessions (12 units of fresh frozen plasma) were conducted in the first 24 hours. Neurological status improved after the first plasmapheresis; hematological abnormalities disappeared in the first few days of therapy. For this patient, the presence of severe neurological symptoms together with fever, thrombocytopenia, and microangiopathic anemia suggested a more complex hematological abnormality, such as TTP. The causal relation between drug and disease is supported by the temporal relation of drug intake with the onset of the clinical symptoms and laboratory abnormalities, as well as by their prompt improvement after the aphaeretic therapy and drug withdrawal.[Ref]

Other

Frequency not reported: Asthenia, fatigue, fever, chills, weakness

Postmarketing reports: Asthenia, edema, chest pain, malaise, fatigue, fever/pyrexia, chills[Ref]

Musculoskeletal

Frequency not reported: Myalgia, moderately severe arthralgias, moderately severe myalgias

Postmarketing reports: Muscle/muscular weakness, muscle spasms/cramps, myalgia, arthralgia[Ref]

Hypersensitivity

Frequency not reported: Hypersensitivity reactions (from mild cutaneous events to anaphylaxis)[Ref]

Respiratory

Frequency not reported: Eosinophilic pneumonia

Postmarketing reports: Dyspnea, pneumonitis of possible allergic etiology, pneumonia[Ref]

A 67-year-old female with a history of pityriasis versicolor experienced eosinophilic pneumonia coincident with infliximab therapy. She was admitted because she had experienced high-grade fever (39C), malaise, productive cough, and dyspnea on exertion during the previous week. She had traveled to South Africa for 8 weeks and had taken this drug (250 mg orally once a week) as malaria prophylaxis. The therapy was continued for 4 weeks after she returned home. A thorough workup led to the diagnosis of eosinophilic pneumonia due to this drug. Her condition improved after the drug was withdrawn.[Ref]

Hepatic

Frequency not reported: Transient elevation of transaminases

Postmarketing reports: Drug-related hepatic disorders (from asymptomatic transient transaminase elevations to hepatic failure), hepatic failure, hepatitis, jaundice, increased asymptomatic transient transaminases (ALT, AST, GGT)

Metabolic

Frequency not reported: Loss of appetite, anorexia

Postmarketing reports: Decreased appetite[Ref]

Renal

Postmarketing reports: Acute renal failure, nephritis, increased blood creatinine

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Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Some side effects may not be reported. You may report them to the FDA.