Lariam Side Effects

Generic name: mefloquine

Medically reviewed by Drugs.com. Last updated on Feb 24, 2025.

Note: This document provides detailed information about Lariam Side Effects associated with mefloquine. Some dosage forms listed on this page may not apply specifically to the brand name Lariam.

Applies to mefloquine: oral tablet.

Important warnings This medicine can cause some serious health issues

Oral route (tablet)

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.

During prophylactic use, if psychiatric or neurologic symptoms occur, the drug should be discontinued and an alternative medication should be substituted

Common side effects of Lariam

Some side effects of mefloquine may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects.

Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common side effects

• diarrhea
• emotional problems
• nausea
• stomach pain

Less common side effects

• abnormal dreams
• loss of appetite
• skin rash

Rare side effects

• loss of hair

Incidence not known

• acid or sour stomach
• belching
• flushing or redness of the skin
• heartburn
• indigestion
• skin rash with a general disease
• stomach discomfort, upset, or pain
• swelling
• unusually warm skin

Serious side effects of Lariam

Along with its needed effects, mefloquine (the active ingredient contained in Lariam) may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur while taking mefloquine:

Rare side effects

• aching joints and muscles
• anxiety
• blistering, loosening, peeling, or redness of the skin
• chest pain or discomfort
• chills
• confusion
• convulsions (seizures)
• cough or hoarseness
• dizziness
• fainting
• fever
• hallucinations (seeing, hearing, or feeling things that are not there)
• irregular, pounding, slow, or fast heartbeat or pulse
• irritability
• lightheadedness
• lower back or side pain
• mental depression
• painful or difficult urination
• pinpoint red spots on the skin
• red or irritated eye
• restlessness
• sore throat
• sores, ulcers, or white spots in the mouth or on the lips
• stiff neck
• swelling of the ankles, feet, or lower legs
• unusual bleeding or bruising
• unusual tiredness or weakness
• vomiting

Incidence not known

• blurred or loss of vision
• continuing ringing or buzzing or other unexplained noise in the ears
• disturbed color perception
• double vision
• feeling of constant movement of self or surroundings
• halos around lights
• hearing loss
• hearing problems
• loss of balance
• loss of bladder control
• muscle spasm or jerking of all extremities
• night blindness
• overbright appearance of lights
• sensation of spinning
• severe or continuing headache
• sudden loss of consciousness
• trouble sleeping
• troubled breathing
• tunnel vision

For healthcare professionals

Applies to mefloquine: oral tablet.

General adverse events

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

• 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]

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

Further information

Lariam side effects can vary depending on the individual. Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Note: Medication side effects may be underreported. If you are experiencing side effects that are not listed, submit a report to the FDA by following this guide.

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