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Lariam Side Effects

Generic Name: mefloquine

Note: This document contains side effect information about mefloquine. Some of the dosage forms listed on this page may not apply to the brand name Lariam.

For the Consumer

Applies to mefloquine: oral tablet


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

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:


  • 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

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

Less Common


  • 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

For Healthcare Professionals

Applies to mefloquine: oral tablet


At the doses used for treatment of acute malaria infections, the side effects possibly associated with mefloquine (the active ingredient contained in Lariam) cannot 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 vomiting (3%).

Due to the long half-life of mefloquine, side effects may occur and persist up to several weeks after drug discontinuation.[Ref]


Psychiatric side effects have included emotional problems and transient emotional disturbances. Behavioral changes, strange or vivid dreams, mania, nightmares, delusions, tension, anger, organic psychosis, and dysphoria have been reported. Sleep disorders (abnormal dreams), anxiety, depression, mood swings, panic attacks, aggression, psychotic or paranoid reactions, suicidal ideation, and suicide have been reported during postmarketing experience.[Ref]


Gastrointestinal side effects have included vomiting, nausea, diarrhea, abdominal pain, and loss of appetite. Mouth ulcers and anorexia have been reported. Nausea, vomiting, abdominal pain, loose stools or diarrhea, dyspepsia, and loss of appetite have been reported during postmarketing experience.[Ref]

Nervous system

Nervous system side effects have included dizziness, syncope, headache, tinnitus, and seizures. Encephalopathy of unknown etiology was reported during prophylactic mefloquine (the active ingredient contained in Lariam) administration; however, the relationship to drug administration could not be established. Weakness and myoclonus have been reported. Dizziness or vertigo, headache, loss of balance, somnolence, sleep disorders (insomnia), sensory and motor neuropathies (including paresthesia, tremor, ataxia), convulsions, agitation or restlessness, memory impairment, confusion, hallucinations, and encephalopathy, and vestibular disorders (including tinnitus and hearing impairment) have been reported during postmarketing experience.[Ref]


Cardiovascular side effects have included extrasystoles and bradycardia. Cardiopulmonary arrest was reported in one patient after a single prophylactic dose while concomitantly using propranolol. Transitory and clinically silent electrocardiograph alterations (including sinus bradycardia, sinus arrhythmia, first degree atrioventricular block, prolongation of the QTc interval, and abnormal T waves) and atrial flutter have been reported. Circulatory disturbances (hypotension, hypertension, flushing, syncope), chest pain, tachycardia or palpitation, bradycardia, irregular heart rate, extrasystoles, atrioventricular block, and other transient cardiac conduction alterations have been reported during postmarketing experience.[Ref]


A 56-year-old male experienced thrombotic thrombocytopenic purpura (TTP) coincident with mefloquine (the active ingredient contained in Lariam) therapy. One 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 two 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]

Hematologic side effects have included decreased hematocrit, leukopenia, leukocytosis, and thrombocytopenia. Anemia, at least 8 cases of isolated thrombocytopenia, at least five cases of hemolytic anemia, and at least one case of thrombotic thrombocytopenic purpura have been reported. Agranulocytosis and aplastic anemia have been reported during postmarketing experience.[Ref]


Dermatologic side effects have included skin rash, hair loss, pruritus, and telogen effluvium. Itching and cutaneous vasculitis have been reported. Rash, exanthema, erythema, urticaria, pruritus, hair loss, hyperhidrosis, erythema multiforme, and Stevens-Johnson syndrome have been reported during postmarketing experience.[Ref]


Other side effects have included asthenia, fatigue, fever, and chills. Asthenia, edema, malaise, fatigue, fever, and chills have also been reported during postmarketing experience.[Ref]


Musculoskeletal side effects have included myalgia. Moderately severe arthralgias and myalgias have been reported. Muscle weakness, muscle cramps, myalgia, and arthralgia have been reported during postmarketing experience.[Ref]


Hypersensitivity side effects have included hypersensitivity reactions ranging from mild cutaneous events to anaphylaxis.[Ref]


Respiratory side effects have included dyspnea and pneumonitis of possible allergic etiology during postmarketing experience. At least one case of eosinophilic pneumonia has been reported.[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 (39 degrees Celsius), malaise, productive cough, and dyspnea on exertion during the previous week. She had traveled to South Africa for 8 weeks and had taken oral mefloquine 250 mg once every 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 the mefloquine therapy. Her condition improved after the drug was withdrawn.[Ref]


Hepatic side effects have included transient elevation of transaminases. Drug-related hepatic disorders from asymptomatic transient transaminase elevations to hepatic failure have been reported during postmarketing experience.


Ocular side effects have included visual disturbances during postmarketing experience.[Ref]


1. "Mefloquine for malaria." Med Lett Drugs Ther 31 (1990): 13-4

2. Jimenez-Huete A, Gil-Nagel A, Franch O "Multifocal myoclonus associated with mefloquine chemoprophylaxis." Clin Neuropharmacol 25 (2002): 243

3. Harinasuta T, Bunnag D, Wernsdorfer WH "A phase II clinical trial of mefloquine in patients with chloroquine-resistant falciparum malaria in thailand." Bull World Health Organ 61 (1983): 299-305

4. Winstanley P "Malaria: treatment." J R Coll Physicians Lond 32 (1998): 203-7

5. Bjorkman A "Acute psychosis following mefloquine prophylaxis." Lancet 2 (1989): 865

6. Caillon E, Schmitt L, Moron P "Acute depressive symptoms after mefloquine treatment." Am J Psychiatry 149 (1992): 712

7. White NJ "Mefloquine." Br Med J 308 (1994): 286-7

8. Croft AMJ, World MJ "Neuropsychiatric reactions with mefloquine chemoprophylaxis." Lancet 347 (1996): 326

9. Van Riemsdijk MM, Ditters JM, Sturkenboom MC, et al. "Neuropsychiatric events during prophylactic use of mefloquine before travelling." Eur J Clin Pharmacol 58 (2002): 441-5

10. Hennequin C, Bouree P, Bazin N, Bisaro F, Feline A "Severe psychiatric side effects observed during prophylaxis and treatment with mefloquine." Arch Intern Med 154 (1994): 2360-2

11. White NJ, Pukrittayakamee S "Clinical malaria in the tropics." Med J Aust 159 (1993): 197-203

12. "Product Information. Lariam (mefloquine)." Roche Laboratories, Nutley, NJ.

13. Weinke T, Trautmann M, Held T, et al "Neuropsychiatric side effects after the use of mefloquine." Am J Trop Med Hyg 45 (1991): 86-91

14. Bem JL, Kerr L, Stuerchler D "Mefloquine prophylaxis: an overview of spontaneous reports of severe psychiatric reactions and convulsions." J Trop Med Hyg 95 (1992): 167-79

15. Piening RB, Young SA "Mefloquine-induced psychosis." Ann Emerg Med 27 (1996): 792-3

16. Phillips M "Adverse events associated with mefloquine - women may be more susceptible to adverse events." BMJ 313 (1996): 1552-3

17. Stuiver PC, Ligthelm RJ, Goud TJ "Acute psychosis after mefloquine." Lancet 2 (1989): 282

18. Speich r, Haller A "Central anticholinergic syndrome with the antimalarial drug mefloquine." N Engl J Med 331 (1994): 57-8

19. Brumbaugh M, Price P, Fagan N, Hsieh H "Psychotic mania associated with mefloquine in a bipolar patient." South Med J 101 (2008): 550-1

20. Meszaros K "Acute psychosis caused by mefloquine prophylaxis?" Can J Psychiatry 41 (1996): 196

21. Overbosch D, Schilthuis H, Bienzle U, et al. "Atovaquone-Proguanil versus Mefloquine for Malaria Prophylaxis in Nonimmune Travelers: Results from a Randomized, Double-Blind Study." Clin Infect Dis 33 (2001): 1015-21

22. Eaton L "Mefloquine has more adverse effects than other drugs for malaria prophylaxis." BMJ 339 (2009): b4167

23. Freedman DO "Clinical practice. Malaria prevention in short-term travelers." N Engl J Med 359 (2008): 603-12

24. Yelmo S, Morera-Fumero AL, Henry M, Renshaw A, Gracia-Marco R "Mania associated with mefloquine prophylaxis." J Clin Psychopharmacol 30 (2010): 339-41

25. Rouveix B, Bricaire F, Michon C, et al "Mefloquine and an acute brain syndrome." Ann Intern Med 110 (1989): 577-8

26. Lobel HO, Bernard KW, Williams SL, et al "Effectiveness and tolerance of long-term malaria prophylaxis with mefloquine: need for a better dosing regimen." JAMA 265 (1991): 361-4

27. Held T, Trautmann M, Weinke T, Mravak S "A prospective clinical trial of the treatment of falciparum malaria with mefloquine, with special reference to neuro-psychiatric side effects." Trans R Soc Trop Med Hyg 85 (1991): 444-5

28. Bakshi R, Hermeling-Fritz I, Gathmann I, Alteri E "An integrated assessment of the clinical safety of artemether-lumefantrine: a new oral fixed-dose combination antimalarial drug." Trans R Soc Trop Med Hyg 94 (2000): 419-24

29. Ekue JM, Ulrich A-M, Rwabwogo-Atenyi J, Sheth UK "A double-blind comparative clinical trial of mefloquine and chloroquine in symptomatic falciparum malaria." Bull World Health Organ 61 (1983): 713-8

30. ter Kuile FO, Nosten F, Thieren M, et al "High-dose mefloquine in the treatment of multidrug-resistant falciparum malaria." J Infect Dis 166 (1992): 1393-400

31. Terkuile FO, Nosten F, Luxemburger C, Kyle D, Tejaisavatharm P, Phaipun L, Price R, Chongsuphajaisiddhi T, White NJ "Mefloquine treatment of acute falciparum malaria: a prospective study of non-serious adverse effects in 3673 patients." Bull World Health Organ 73 (1995): 631-42

32. De Souza J-M "A phase I clinical trial of mefloquine in brazilian male subjects." Bull World Health Organ 61 (1983): 809-14

33. Choo V "Uncertainty about mefloquine will take time to resolve." Lancet 347 (1996): 891

34. Olson PE, Kennedy CA, Morte PD "Paresthesias and mefloquine prophylaxis." Ann Intern Med 117 (1992): 1058-9

35. Gullahorn GM, Bohman HR, Wallace MR "Anaesthesia emergence delirium after mefloquine prophylaxis." Lancet 341 (1993): 632

36. Ruff TA, Sherwen SJ, Donnan GA "Seizure associated with mefloquine for malaria prophylaxis." Med J Aust 161 (1994): 453

37. Jallon P "Use of mefloquine in epileptic patients." J Neurol Neurosurg Psychiatry 51 (1988): 732

38. Singh K, Shanks GD, Wilde H "Seizures after mefloquine." Ann Intern Med 114 (1991): 994

39. Lench P "Malaria prophylaxis - psychological problems after mefloquine and chloroquine." BMJ 311 (1995): 192

40. Nosten F, ter Kuile FO, Luxemburger C, et al "Cardiac effects of antimalarial treatment with halofantrine." Lancet 341 (1993): 1054-6

41. Terkuile FO, Luxemburger C, Nosten F, Thwai KL, Chongsuphajaisiddhi T, White NJ "Predictors of mefloquine treatment failure: a prospective study of 1590 patients with uncomplicated falciparum malaria." Trans R Soc Trop Med Hyg 89 (1995): 660-4

42. Kozarsky P, Eaton M "Use of mefloquine for malarial chemoprophylaxis in its first year of availability in the United States." Clin Infect Dis 16 (1993): 185-6

43. Fonteyne W, Bauwens A, Jordaens L "Atrial flutter with 1:1 conduction after administration of the antimalarial drug mefloquine." Clin Cardiol 19 (1996): 967-8

44. Stracher AR, Stoeckle MY, Giordano HF "Aplastic anemia during malarial prophylaxis with mefloquine." Clin Infect Dis 18 (1994): 263-4

45. Fiaccadori E, Maggiore U, Rotelli C, et al. "Thrombotic-thrombocytopenic purpura following malaria prophylaxis with mefloquine." J Antimicrob Chemother 57 (2005): 160-1

46. Martin GJ, Malone JL, Ross EV "Exfoliative dermatitis during malarial prophylaxis with mefloquine." Clin Infect Dis 16 (1993): 341-2

47. Scerri L, Pace JL "Mefloquine-associated cutaneous vasculitis." Int J Dermatol 32 (1993): 517-8

48. White AC "Cutaneous vasculitis associated with mefloquine." Ann Intern Med 123 (1995): 894

49. Van Den Eden E, Van Gompel A, Colebunders R, Van Den Ende J "Mefloquine-induced Stevens-Johnson syndrome." Lancet 337 (1991): 683

50. Shlim DR "Severe facial rash associated with mefloquine." JAMA 266 (1991): 2560

51. Katsenos S, Psathakis K, Nikolopoulou MI, Constantopoulos SH "Mefloquine-induced eosinophilic pneumonia." Pharmacotherapy 27 (2007): 1767-71

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.