500MG SULPHAMETHOXYPYRAZINE + 25MG PYRIMETHAMINE
COMPOSITION
Each Metafizin® 525mg contains Sulphamethoxypyrazine 500mg and pyrimethamine 25mg.
PHARMACOLOGICAL PROPERTIES
Metafizin® contains Sulphamethoxypyrazine and pyrimethamine which act at different points of the metabolic pathway of the parasite. Sulphamethoxyprazine prevents the synthesis of dihydropteroate, an intermediate in dihydrofolate formation, by inhibiting the enzyme dihydropteroate synthetase while pyrimethamine inhibits the conversion of dihydrofolic acid to tetrahydrofolic acid- a reaction catalyzed by the enzyme dihydrofolic reductase. The tetrahydrofolic acid is the coenzyme that acts as an acceptor of a variety of one carbon unit and participates in several metabolic reactions. This type of impairment of the parasite’s metabolism is termed sequential blockade.
INDICATIONS
Metafizin® Tablets is used for intermittent preventive treatment (IPT) of malaria in pregnancy.
Metafizin® is indicated in the treatment of malaria caused by Plasmodium falciparum, Plasmodium vivax, P. malariae and P. ovale.
DOSAGE AND ADMINISTRATION
Adults: 2 tablets as a single dose, 3 tablets for adults over
70 kg body weight.
Children: 5 to 9 years ½ -1 tablet
10 -14 years 1 – 2 tablets
Over 14 years 2 tablets
Under 5 years 25mg / kg body weight (with reference
to Sulphamethoxypyrazine) in one single
dose.
Antimalaria prophylaxis; Half therapeutic dose should be administered weekly according to the age of the patient.
For Pregnancy:
One full treatment dose during the 2nd and 3rd trimesters. The last dose should be given not later than one month before the expected date of delivery (second trimester starts from the sixteenth week of pregnancy or when the pregnant woman notices the kicking of the baby).
Sulphamethoxypyrazine and pyrimethamine in Metafizin belong to the antifoliate group of antimalarials. Therefore folic acid supplement should be delayed for one week after the use of the drug to avoid inhibitory effect on the antimalarial action.
SIDE EFFECTS
Metafizin® is well tolerated at the recommended doses. Nausea and vomiting are seldom reported. Haematological anomalies e.g thrombocytopenia purpura, leukopenia, neutropenia and agranulocytosis must be taken into consideration because of the Sulphonamide constituent. The condition is reversible if the treatment ceases. This is common in elderly patients.
PRECAUTIONS
Metafizin® tablets should be administered in pregnant women under strict medical supervision. If a cutaneous erythema appears, stop treatment immediately.
KEEP OUT OF THE REACH OF CHILDREN!
CONTRAINDICATIONS
Metafizin® tablets is contraindicated in pregnant women during the last two weeks of pregnancy or in infants during the first two weeks of life. Metafizin® is contraindicated in patients with marked damage to hepatic parenchyma, severe renal insufficiency or blood dyscrasia.
Patients who are hypersensitive to sulphonamide or pyrimethamine.
OVERDOSE
Symptoms of overdosage include vomiting, nausea, visual and mental disorders, purpura and jaundice. Treatment is symptomatic and includes forced diuresis, gastric lavage which should be carried out as early as possible.
STORAGE CONDITION
Store below 30oC in a cool dry place. Protect from light.
PRESENTATION
Metafizin® Tablets is available in a strip of 2 tablets in a pack and 3 tablets in a pack.