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Mefloquine
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Malaria
- a killer returns
- Incidence
of malaria on the rise due to resistance of mosquito (the vector)
to insecticides and of Plasmodium (the parasite) to antimalarial drugs
- Sharp increase in deaths from malaria
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Antimalarial
Therapy
- Chloroquine
is the mainstay of therapy
- Quinine is old yet effective
- Other antimalarials are amodiaquine, proguanil, pyrimethamine, mepacrine
- Primaquine for falciparum malaria
- Mefloquine, artemisinin, artemether, artesunate are newer agents
- Sulfonamides, trimethoprim, tetracyclines and quinolone have some
antimalarial activity
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Limitations
of Existing Antimalarial Therapy
- Resistance
to chloroquine is common
- Plasmodium falciparum infections are particularly a threat because
of severity of infection and drug resistance
- Adverse effects with quinine
- Other agents are not as effective as first line therapy
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Mefloquine
- Acts
against malarial parasite at erythrocytic phase
- Schizonticidal
- Effective against P. falciparum and P. vivax
- Effective even in chloroquine and quinine resistant cases
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Pharmacokinetics
Absorption
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Well absorbed from GI tract
- Peak concentrations in 6 hours
Distribution
- Widely distributed
Elimination
- Half life : 21 days
- Drug persists in the body
- Mefloquine and metabolite mainly excreted in bile anf faeces
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Dosage
Single
dose 1000 mg or 15 mg/kg body wt.
In multidrug
resistant cases 25 mg/kg in 2 divided doses
Administer
with a 250 ml water (vomiting following administration reduces the
drug availability in the body)
For
prophylaxis
250 mg or 5 mg/kg once weekly 1-2 weeks before entering a malarial
area and continuing for 4 months after leaving
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Contraindications
- Pregnancy
- 1st trimester
- Children < 3 months age or < 5 kg weight
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Indications
- Chloroquine
and multi drug resistant Plasmodium falciparum or vivax infection
- Prophylaxis in endemic areas
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Salient Features
- Used in
treatment of chloroquine resistant and multi drug resistant malaria
due to P.falciparum or P.vivax
- Near 100% success rates
- A drug of choice in cerebral malaria
- Convenient single dose administration
- Long half life, hence persistence of drug in the body, preventing
recrudescence
- May be used alone or with other antimalarial drugs, if necessary
- May be used for prophylaxis
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