Mefloquine

Mechanism-of-action class: Unknown Cellular or Molecular Interaction.

• 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.ICD-10: B54

• Use of mefloquine hydrochloride tablets is contraindicated in patients with a known hypersensitivity to mefloquine or related compounds (e.g., quinine and quinidine) or to any of the excipients contained in the formulation. Mefloquine hydrochloride tablets should not be prescribed for prophylaxis in patients with active depression, a recent history of depression, generalized anxiety disorder, psychosis, schizophrenia or other major psychiatric disorders, or with a history of convulsions.contraindicated

Malaria Treatment in Adults Treatment of mild to moderate malaria in adults caused by mefloquine-susceptible strains of P. falciparum or by P. vivax: Dosage: Five tablets (1250 mg) mefloquine hydrochloride to be given as a single oral dose. The drug should not be taken on an empty stomach and should be administered with at least 8 oz (240 mL) of water. If a full-treatment course with mefloquine does not lead to improvement within 48 to 72 hours, mefloquine should not be used for retreatment. An alternative therapy should be used. Similarly, if previous prophylaxis with mefloquine failed, mefloquine should not be used for curative treatment (see INDICATIONS AND USAGE ). Note: Patients with acute P. vivax malaria, treated with mefloquine, are at high risk of relapse because mefloquine does not eliminate exoerythrocytic (hepatic phase) parasites. To avoid relapse after initial treatment of the acute infection with mefloquine, patients should subsequently be treated with an 8-aminoquinoline derivative (e.g., primaquine). Malaria Prophylaxis in Adults Dosage: One 250 mg mefloquine hydrochloride tablet once weekly. Prophylactic drug administration should begin 1 week before arrival in an endemic area. Subsequent weekly doses should be taken regularly, always on the same day of each week, preferably after the main meal. To reduce the risk of malaria after leaving an endemic area, prophylaxis must be continued for 4 additional weeks to ensure suppressive blood levels of the drug when merozoites emerge from the liver.

In case of life-threatening, serious or overwhelming malaria infections due to P. falciparum, patients should be treated with an intravenous antimalarial drug. Following completion of intravenous treatment, mefloquine may be given to complete the course of therapy. QTc Interval Prolongation and Drug Interactions Halofantrine should not be administered with mefloquine or within 15 weeks of the last dose of mefloquine due to the risk of a potentially fatal prolongation of the QTc interval (see CLINICAL PHARMACOLOGY, Pharmacokinetics, Elimination ). Ketoconazole should not be administered with mefloquine or within 15 weeks of the last dose of mefloquine due to the risk of a potentially fatal prolongation of the QTc interval. Ketoconazole increases plasma concentrations and elimination half-life of mefloquine following coadministration (see CLINICAL PHARMACOLOGY, Pharmacokinetics, Elimination and PRECAUTIONS, Drug Interactions ). Concomitant administration of mefloquine and quinine or quinidine may produce electrocardiographic abnormalities. Psychiatric and Neurologic Adverse Reactions Mefloquine may cause neuropsychiatric adverse reactions in adults and children. Neuropsychiatric symptoms can be difficult to identify in children. Therefore, vigilance is required to monitor for the occurrence of these symptoms, especially in nonverbal children. Psychiatric Adverse Reactions Psychiatric symptoms ranging from anxiety, paranoia, and depression to hallucinations and psychotic behavior can occur with mefloquine use. Symptoms may occur early in the course of mefloquine use.

Clinical At the doses used for treatment of acute malaria infections, the symptoms possibly attributable to drug administration cannot be distinguished from those symptoms usually attributable to the disease itself. Among subjects who received mefloquine for prophylaxis of malaria, the most frequently observed adverse experience was vomiting (3%). Dizziness, syncope, extrasystoles and other complaints affecting less than 1% were also reported. Two serious adverse reactions were cardiopulmonary arrest in one patient shortly after ingesting a single prophylactic dose of mefloquine while concomitantly using propranolol (see PRECAUTIONS, Drug Interactions ), and encephalopathy of unknown etiology during prophylactic mefloquine administration. The relationship of encephalopathy to drug administration could not be clearly established. Among subjects who received mefloquine for treatment, the most frequently observed adverse experiences included: dizziness, myalgia, nausea, fever, headache, vomiting, chills, diarrhea, skin rash, abdominal pain, fatigue, loss of appetite, and tinnitus. Those side effects occurring in less than 1% included bradycardia, hair loss, emotional problems, pruritus, asthenia, transient emotional disturbances and telogen effluvium (loss of resting hair). Seizures have also been reported. Laboratory The most frequently observed laboratory alterations which could be possibly attributable to drug administration were decreased hematocrit, transient elevation of transaminases, leukopenia and thrombocytopenia.

Pregnancy

Symptoms and Signs In cases of overdosage with mefloquine, the symptoms mentioned under ADVERSE REACTIONS may be more pronounced. Treatment Patients should be managed by symptomatic and supportive care following mefloquine overdose. There are no specific antidotes. Monitor cardiac function (if possible by ECG) and neuropsychiatric status. Provide symptomatic and intensive supportive treatment as required.

• Feb 20, 2002ANDAANDA076175Chartwell Rx
• Dec 29, 2003ANDAANDA076392Barr

1. 1Anxiety3724%
2. 2Depression3321%
3. 3Insomnia3321%
4. 4Dizziness2416%
5. 5Headache2013%
6. 6Diarrhoea1711%
7. 7Nausea1610%
8. 8Abnormal Dreams149.1%
9. 9Nightmare149.1%
10. 10Tinnitus149.1%
11. 11Confusional State138.4%
12. 12Hallucination127.8%
13. 13Suicidal Ideation127.8%
14. 14Vomiting127.8%
15. 15Fatigue117.1%

Recent PubMed references pinned to Mefloquine as a MeSH major topic. Citations link to pubmed.ncbi.nlm.nih.gov.

• Comparison of the effect of donepezil and a combination of donepezil and mefloquine (THN201) on cognition during a scopolamine challenge in healthy participants.
  Experimental and clinical psychopharmacology · 2026 · Dondaine T, Rein W, Micallef J, et al.
  PMID 41989444DOI 10.1037/pha0000825
• Examination of Coligands in Mefloquine-Metal Complexes Reveals the Structural Determinants of Activity against Plasmodium falciparum and Schistosoma mansoni.
  Journal of medicinal chemistry · 2026 · Villarreal W, Quadros HC, Colina-Vegas L, et al.
  PMID 41811093DOI 10.1021/acs.jmedchem.5c03739
• Pharmacokinetic and pharmacodynamic modeling of anti-plasmodial drugs mefloquine plus artesunate: insights on translational application.
  Antimicrobial agents and chemotherapy · 2026 · Mim SR, Vieira Santos V, Pereira LC, et al.
  PMID 41677257DOI 10.1128/aac.01717-25
• A common DNA deletion altering the 3'UTR of mdr1 is associated with reduced mefloquine susceptibility in P. vivax parasites from Cambodian patients.
  Nature communications · 2026 · Ko K, Tebben K, Andrianinarivomanana T, et al.
  PMID 41571698DOI 10.1038/s41467-026-68456-7
• Innovative application of mefloquine and Methacycline in combating Tet(X3/X4)-positive Escherichia coli infections.
  BMC microbiology · 2025 · Zhou Q, Xue J, Li J, et al.
  PMID 41462086DOI 10.1186/s12866-025-04516-0
• Structural basis of PANX1 permeation and positive modulation by mefloquine.
  Nature communications · 2025 · Li Y, Ruan Z, Lee J, et al.
  PMID 41381453DOI 10.1038/s41467-025-66028-9
• Tolerance of Plasmodium falciparum mefloquine-resistant clinical isolates to mefloquine-piperaquine with implications for triple artemisinin-based combination therapies.
  Nature communications · 2025 · Roesch C, Cosson A, Mairet Khedim M, et al.
  PMID 41309585DOI 10.1038/s41467-025-65629-8
• Niosomal mefloquine and cisplatin in breast cancer: comparative effects on apoptosis and angiogenesis via in vitro and in silico analysis.
  BMC cancer · 2025 · Salari Z, Khosravi A, Riahi A, et al.
  PMID 41291614DOI 10.1186/s12885-025-15372-6

The 10 most recently updated of 70 ClinicalTrials.gov registrations naming Mefloquine as an intervention. Registration is not evidence of efficacy or safety — reference crosswalk only.

• FocaL Mass Drug Administration for Vivax Malaria Elimination
  Recruiting · Phase 3 · Interventional · 7,530 enrolled · University of California, San Francisco
  NCT05690841updated 2026-06-09
• Targeting High Risk Populations With Enhanced Reactive Focal Mass Drug Administration in Thailand
  Completed · Interventional · 14,977 enrolled · University of California, San Francisco
  NCT05052502updated 2026-04-29
• A Trial to Compare the Efficacy, Safety and Tolerability of Combinations of 3 Anti-malarial Drugs Against Combina-tions of 2 Anti-malarial Drugs.
  Completed · Phase 3 · Interventional · 2,583 enrolled · University of Oxford
  NCT03923725updated 2025-11-18
• Temozolomide, Memantine Hydrochloride, Mefloquine, and Metformin Hydrochloride in Treating Patients With Glioblastoma Multiforme After Radiation Therapy
  Terminated · Phase 1 · Interventional · 144 enrolled · M.D. Anderson Cancer Center
  NCT01430351updated 2025-05-07
• A Trial to Compare the Efficacy, Safety and Tolerability of Combinations of 3 Anti-malarial Drugs Against Combinations of 2 Anti-malarial Drugs (Asia)
  Completed · Phase 3 · Interventional · 103 enrolled · University of Oxford
  NCT03939104updated 2024-03-20
• Safety and Efficacy of NF135 CPS Immunization
  Terminated · Interventional · 43 enrolled · Radboud University Medical Center
  NCT03813108updated 2023-05-26
• Efficacy of Mefloquine as Prophylaxis Against COVID-19: A Placebo-control, Randomized Clinical Trial
  Completed · Phase 2 · Phase 3 · Interventional · 137 enrolled · Helwan University
  NCT04847661updated 2023-03-06
• Study of Efficacy and Safety of TL-FVP-t vs. SOC in Patients With Mild to Moderate COVID-19
  Completed · Phase 3 · Interventional · 168 enrolled · R-Pharm
  NCT04501783updated 2023-01-20
• Compare the Effectiveness Between Existing Treatment and New Treatment
  Terminated · Interventional · 76 enrolled · University of Oxford
  NCT01640587updated 2023-01-10
• Study to Compare the Triple ACT AL+AQ With the ACT AL in Cambodia and Vietnam
  Completed · Phase 3 · Interventional · 310 enrolled · University of Oxford
  NCT03355664updated 2022-07-15

Frequently asked questions

How does Mefloquine work?

Mechanism-of-action class: Unknown Cellular or Molecular Interaction.

What is Mefloquine used for?

According to FDA labeling, Mefloquine carries indications including: 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.. This is a reference summary of labeled uses, not medical advice or a treatment recommendation.

What class of drug is Mefloquine?

Mefloquine is classified as Methanolquinolines, Antimalarial, Unknown Cellular or Molecular Interaction.

What are the contraindications for Mefloquine?

Mefloquine labeling lists contraindications including: Use of mefloquine hydrochloride tablets is contraindicated in patients with a known hypersensitivity to mefloquine or related compounds (e.g., quinine and quinidine) or to any of the excipients contained in the formulation. Mefloquine hydrochloride tablets should not be prescribed for prophylaxis in patients with active depression, a recent history of depression, generalized anxiety disorder, psychosis, schizophrenia or other major psychiatric disorders, or with a history of convulsions.. Always consult the full prescribing information and a clinician.