Mefloquine

Indications

Mefloquine is used for: Malaria

Adult Dose

Oral Acute Malaria Adult: 5 tablets (Total 1250 mg) as a single oral dose. OR 750 mg orally as initial dose, followed by 500 mg orally 6 to 12 hours after initial dose. Total dose 1,250 mg. Malaria prophylaxis 250 mg once weekly, taken 1-3 wk before exposure and continuing for 4 wk after leaving the endemic area. Dosing Considerations If a full-treatment course does not lead to improvement within 48-72 hr, 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

Child Dose

Oral Acute Malaria <6 months old: Safety and efficacy not established Child: >6 months: 20-25 mg/kg PO as single dose. Maximum total dose: 1250 mg. OR 15 mg/kg as initial dose, followed by 10 mg/kg po given 6-12 hours after initial dose. Total dose= 25 mg/kg Malaria prophylaxis Child: 5 to <10 kg: 31.25 mg (1/8 tablet) PO qWeek 10 to <20 kg: 62.5 mg (1/4 tablet) PO qWeek 20 to <30 kg: 125 mg (1/2 tablet) PO qWeek 30-45 kg: 187.5 mg (3/4 tablet) PO qWeek >45 kg: 250 mg (1 tablet) PO qWeek Start 1-2 weeks before arrival in endemic area; continue 4 weeks after leaving endemic area

Renal Dose

Administration

Should be taken with food. Best taken w/ meals & a full glass of water. Should be taken on the same day of each week.

Contra Indications

Hypersensitivity to related compounds (e.g. quinine and quinidine); history of blackwater fever;, prophylactic use in patients w/ history of psychiatric (including depression) or convulsive disorders; retreatment w/ mefloquine. Severe hepatic impairment. Concomitant use w/ halofantrine.

Precautions

Epilepsy; delay admin until at least 12 hr after the last dose of quinine/quinine-related compounds (monitoring of cardiac and neurological functions is warranted). Avoid driving or operating machines during and up to 3 wk after mefloquine use. Pregnancy, lactation; cardiac conduction disturbances; children <3 mth or 5 kg. Lactation: Minimally excreted in human breast milk; based on a study in a few subjects, low concentrations (3% to 4%) excreted; caution advised

Pregnancy-Lactation

Pregnancy Category: B Lactation: Minimally excreted in human breast milk; based on a study in a few subjects, low concentrations (3% to 4%) excreted; caution advised

Interactions

Increased risk of ECG abnormalities w/ quinine or chloroquine, antihistamines, TCAs and phenothiazines. May increase risk of seizure w/ quinidine or quinine. Concomitant use w/ valproic acid, phenobarbital, carbamazepine and phenytoin may cause loss of seizure control and lower plasma levels of anticonvulsants. Increased risk of QT prolongation and arrhythmia w/ ketoconazole. Concomitant use w/ digoxin, Ca-channel blockers, antiarrhythmics and ?-blockers may increase the risk of cardiotoxicity. Increased risk of ventricular arrhythmias w/ amiodarone. Concomitant use w/ TCAs, SSRIs, buprion, antipsychotic, tramadol may increase the risk of convulsions. Increased plasma levels w/ metoclopromide. May compromise adequate immunisation by live typhoid vaccine. Vaccinations w/ attenuated live bacteria should be completed at least 3 days prior the 1st dose of mefloquine. Potentially Fatal: Avoid concomitant use w/ halofantrine as potentially fatal cardiac arrhythmias may occur.

Adverse Effects

Side effects of Mefloquine : 1-10% Anxiety, Difficulty concentrating, Headache, Insomnia, Lightheadedness, Vertigo, Vomiting, Diarrhea, Stomach pain, Nausea, Visual disturbances, Tinnitus Frequency Not Defined Suicidal depression, Psychiatric Sx, Pneumonitis, Seizure, Abnormal ECG Potentially Fatal: Seizures, thrombocytopenia, leucopenia, AV block, encephalopathy.

Mechanism of Action

Mefloquine is a 4-methanolquinine antimalarial agent and a blood schizontocide which acts by interfering w/ the parasite's ability to metabolise and utilise erythrocyte Hb. It is active against most Plasmodium sp and is used for prophylaxis and treatment against malaria.