Mefloquine

Mefloquine is indicated in-

• Acute Malaria Infections caused by Mefloquine-susceptible strains of Plasmodium falciparum (both chloroquine- susceptible and resistant strains) or by P. vivax
• Prophylaxis of P. falciparum and P. vivax malaria infections

Mefloquine has been found to produce swelling of the Plasmodium falciparum food vacuoles. It may act by forming toxic complexes with free heme that damage membranes and interact with other plasmodial components.

Mefloquine is an antimalarial agent which acts as a blood schizonticide. Mefloquine is active against the erythrocytic stages of Plasmodium species. However, the drug has no effect against the exoerythrocytic (hepatic) stages of the parasite. Mefloquine is effective against malaria parasites resistant to chloroquine. Mefloquine is a chiral molecule. According to some research, the (+) enantiomer is more effective in treating malaria, and the (-) enantiomer specifically binds to adenosine receptors in the central nervous system, which may explain some of its psychotropic effects.

Adult:

• Malaria prevention: 1 tablet (250 mg) once per week starting 1-2 weeks before departure and continued for 4 weeks after leaving malarious area.
• Malaria treatment: 5 tablets (5X250 mg) in a single dose (up to max. 1.5 gm) or preferably in 2 divided doses 6 to 8 hours apart.

In Children 6 Months and Older:

• Malaria prevention: Approximately 5 mg/kg body weight once per week (250 mg for children weighing over 45 kg, decreasing in proportion to body weight for children weighing 45 kg or less).
• Malaria treatment: 20 to 25 mg/kg body weight which may be split into two doses 6 to 8 hours apart to reduce the occurrence or severity of adverse reactions.

Geriatric Use: Experiences have not identified differences in responses between the elderly and younger patients.

Should be taken with food. Best taken with meals & a full glass of water.

Increased risk of ECG abnormalities with quinine or chloroquine, antihistamines, TCAs and phenothiazines. May increase risk of seizure with quinidine or quinine. Concomitant use with 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 with ketoconazole. Concomitant use with digoxin, Ca channel blockers, antiarrhythmics and β-blockers may increase the risk of cardiotoxicity. Increased risk of ventricular arrhythmias with amiodarone. Concomitant use with TCAs, SSRIs, buprion, antipsychotic, tramadol may increase the risk of convulsions. Increased plasma levels with metoclopromide. May compromise adequate immunisation by live typhoid vaccine. Vaccinations with attenuated live bacteria should be completed at least 3 days prior the 1st dose of mefloquine.

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

Among subjects who received Mefloquine for prophylaxis of malaria, following side effects was observed:

• The most frequently observed sied-effects were vomiting, dizziness, syncope, extrasystoles and other complaints affecting less than 1%. Among subjects who received Mefloquine for treatment, following side-effects was observed:
• The most frequently observed side-effects included : dizziness, myalgia, nausea, fever, headache, vomiting, chills, diarrhoea, skin rash, abdominal pain fatigue, loss of appetite, and tinnitus

Use in Pregnancy: There is no adequate and well-controlled study in pregnant women. However, clinical experience with Mefloquine has not revealed an embrytoxic or teratogenic effect. Mefloquine should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.

Use in Nursing Mothers: Mefloquine is excreted in breast milk in small amounts. the activity of which is unknown. Because of the potential for serious adverse reactions in nursing infants form Mefloquine. a decision should be made whether to discontinue the drug taking into account the importance of the drug to the mother.

Warnings: Mefloquine may cause psychiatric symptoms in a number of patients, ranging from anxiety, paranoia, and depression to hallucinations and psychotic behavior. Rare cases of suicidal ideation and suicide have been reported though no relationship to drug administration has been confirmed. Mefloquine should be used with caution in patients with a previous history of depression. Concomitant administration of Mefloquine and quinine or quinidine may produce electrocardiographic abnormalities and may increase risk of convulsions.

Precautions: In patients with epilepsy, Mefloquine may increase the risk of convulsions. Caution should be exercised with regard to activities requiring alertness and fine motor coordination such as driving, piloting aircraft and operating machinery. Mefloquine should be used with caution in patients with psychiatric disturbances. In patients with impaired liver function the elimination of Mefloquine may be prolonged, leading to higher plasma levels.

In cases of overdosage with Mefloquine, the symptoms may be more pronounced. The following procedure is recommended in case of overdosage:

• Induce vomiting or perform gastric lavage, as appropriate.
• Monitor cardiac function (if possible by ECG), neurologic and psychiatric status for at least 24 hours.
• Provide Symptomatic and intensive supportive treatment as required, particularly of cardiovascular disturbance.
• Treat vomiting or diarrhoea with standard fluid therapy.

Anti-malarial drugs

Store in a cool dry place. Protect from light.