Adult: For uncomplicated infection caused by mefloquine-susceptible P. falciparum or P. vivax: 20-25 mg/kg split into 2-3 doses 6-8 hourly. If vomiting occurs <30 minutes, a 2nd full dose should be given; if it occurs 30-60 minutes after a dose, an additional half dose should be given. Consider alternative treatments if no improvement within 48-72 hours.
Oral Prophylaxis of malaria
Adult: For infections caused by P. falciparum and P. vivax, including chloroquine-resistant strains of P. falciparum for travellers to endemic area: 250 mg once weekly starting >2 weeks before arrival at endemic area. Continue weekly treatment during travel, and for 4 weeks after leaving endemic area. Treatment recommendations may vary due to geographical resistance patterns and cross-resistance, consider national and international guidelines for appropriate use and recommendations. Child: Weight-based dosing: 5 mg/kg once weekly. Fixed dosing as 250 mg tab: 19 kg: 1/4 tab; >19-30 kg: 1/2 tab; >30-45 kg: 3/4 tab; >45 kg: 1 tab. All doses to be taken once weekly starting >2 weeks before arrival at endemic area. Continue weekly treatment during travel, and for 4 weeks after leaving endemic area. Treatment recommendations may vary due to geographical resistance patterns and cross-resistance, consider national and international guidelines for appropriate use and recommendations.
Administration
Should be taken with food. Best taken w/ meals & a full glass of water.
Contraindications
Hypersensitivity to mefloquine and related compounds (e.g. quinidine, quinine). Prophylactic use in patients with psychosis, generalised anxiety disorder, suicidal ideations, behaviour, or attempts, active and recent history of depression, history of convulsions of any origin, schizophrenia, or other major psychiatric disorders; history of Blackwater fever. Concomitant use with halofantrine or within 15 weeks after the last dose of mefloquine.
Special Precautions
Patient with significant cardiac disease; previous history of depression; history of convulsions (if used as treatment). In cases of life-threatening, serious, or overwhelming P. falciparum malarial infections, patients should be treated with IV antimalarial drugs and mefloquine may be given orally to complete the course. Renal and hepatic impairment. Children. Pregnancy and lactation.
Adverse Reactions
Significant: Neuropsychiatric effects (e.g. attempted suicide, suicidal thoughts and behaviour, anxiety disorders, depression, bipolar disorder, paranoia, hallucinations, mood swings, panic attacks, psychotic and paranoid reactions, insomnia, abnormal dreams or nightmares, restlessness, confusion, dizziness, vertigo, loss of balance); hypersensitivity reactions; altered cardiac conduction (e.g. ECG alterations, 1st-degree atrioventricular block, sinus bradycardia, sinus arrhythmia, QTc interval prolongation, abnormal T waves); increase risk of convulsions in patients with epilepsy; polyneuropathy; ocular effects (e.g. retinal disorders, optic neuropathy); pneumonitis of possible allergic aetiology; agranulocytosis, aplastic anaemia; hypoglycaemia (particularly in patients with congenital hyperinsulinaemic hypoglycaemia). Blood and lymphatic system disorders: Leucopenia, leucocytosis, thrombocytopenia. Cardiac disorders: Extrasystoles. Ear and labyrinth disorders: Vestibular disorders, tinnitus, impaired hearing, hyperacusis, partial deafness (sometimes prolonged). Eye disorders: Visual impairment, blurred vision, cataract. Gastrointestinal disorders: Nausea, vomiting, diarrhoea, abdominal pain, dyspepsia, pancreatitis. General disorders and administration site conditions: Asthenia, malaise, fatigue, pyrexia, chills, chest pain, oedema. Hepatobiliary disorders: Hepatitis, jaundice, hepatic failure. Investigations: Transient increased in ALT, AST, gamma-glutamyl transferase (GGT); increased blood creatinine, decreased haematocrit. Metabolism and nutrition disorders: Decreased appetite. Musculoskeletal and connective tissue disorders: Arthralgia, myalgia, muscle weakness and spasms. Nervous system disorders: Cranial nerve paralysis, amnesia, somnolence, speech disorder, memory impairment, gait disturbance, balance disorder, peripheral sensory and motor neuropathy including paraesthesia, tremor, and ataxia. Renal and urinary disorders: Nephritis, acute renal failure. Respiratory, thoracic and mediastinal disorders: Pneumonia, dyspnoea. Skin and subcutaneous tissue disorders: Pruritus, Stevens-Johnson syndrome, rash, erythema multiforme, urticaria, hyperhidrosis, alopecia. Vascular disorders: Hypotension, hypertension, flushing, syncope.
This drug may cause dizziness, and vertigo, if affected, do not drive or operate machinery.
Monitoring Parameters
Monitor LFTs, evaluate neuropsychiatric effects, and perform eye examinations periodically if to be administered for a prolonged period. Monitor blood concentration of anti-seizure medicines if used concomitantly with mefloquine.
Overdosage
Symptoms: Vertigo, dizziness, nausea, hypotension, tachycardia, hallucinations. Management: Supportive and symptomatic treatment. Monitor cardiac function and neuropsychiatric status.
Drug Interactions
Increased plasma concentration and elimination half-life with ketoconazole. May cause ECG abnormalities and increase the risk of convulsions with other related compounds (e.g. chloroquine, quinine, quinidine). May diminish the therapeutic effect by lowering the plasma concentrations of anticonvulsants (e.g. carbamazepine, valproic acid, phenytoin, phenobarbital). May increase the risk of convulsions with TCAs, SSRIs, bupropion, tramadol, antipsychotics, or some antibiotics. Decreased plasma concentration with CYP3A4 inducers (e.g. rifampicin).
Potentially Fatal: May enhance the QTc prolonging effect of halofantrine.
Action
Description: Mefloquine is a quinoline-methanol antimalarial agent which acts as a blood schizonticide by destructing the asexual intraerythrocytic forms of human malarial pathogens such as Plasmodium falciparum, P. vivax. Pharmacokinetics: Absorption: Well absorbed from the gastrointestinal tract. Bioavailability: Increased with food. Time to peak plasma concentration: Approx 17 hours (range: 6-24 hours). Distribution: Distributes into blood, erythrocytes, CSF, and tissues. Crosses the placenta; enters breast milk (small amount). Volume of distribution: Approx 20 L/kg. Plasma protein binding: Approx 98%. Metabolism: Extensively metabolised in the liver by CYP3A4 isoenzyme to 2,8-bis-trifluoromethyl-4-quinoline carboxylic acid (inactive) and other metabolites. Excretion: Mainly via bile and faeces; urine (9% as unchanged drug; 4% as metabolite). Elimination half-life: Approx 3 weeks (range: 2-4 weeks).
Chemical Structure
Mefloquine Source: National Center for Biotechnology Information. PubChem Compound Summary for CID 4046, Mefloquine. https://pubchem.ncbi.nlm.nih.gov/compound/Mefloquine. Accessed Sept. 28, 2022.
P01BC02 - mefloquine ; Belongs to the class of methanolquinoline antimalarials.
References
Anon. Mefloquine. AHFS Clinical Drug Information [online]. Bethesda, MD. American Society of Health-System Pharmacists, Inc. https://www.ahfscdi.com. Accessed 05/08/2022.Anon. Mefloquine. Lexicomp Online. Hudson, Ohio. Wolters Kluwer Clinical Drug Information, Inc. https://online.lexi.com. Accessed 05/08/2022.Buckingham R (ed). Mefloquine Hydrochloride. Martindale: The Complete Drug Reference [online]. London. Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 05/08/2022.Joint Formulary Committee. Mefloquine. British National Formulary [online]. London. BMJ Group and Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 05/08/2022.Lariam (Roche Singapore Pte Ltd). MIMS Singapore. http://www.mims.com/singapore. Accessed 05/08/2022.Lariam 250 mg Tablets (Neon Healthcare Ltd.). MHRA. https://products.mhra.gov.uk. Accessed 05/08/2022.Medicines for the Prevention of Malaria While Traveling: Mefloquine. Centers for Disease Control and Prevention. https://www.cdc.gov. Accessed 05/08/2022.Mefloquine Hydrochloride Tablet (A-S Medication Solutions). DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed. Accessed 05/08/2022.Pharmaco (NZ) Ltd. Lariam 250 mg Tablets data sheet 04 October 2018. Medsafe. http://www.medsafe.govt.nz. Accessed 05/08/2022.
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