Fansidar Information
Fansidar (Pyrimethamine)
Fansidar (Pyrimethamine) Description
Fansidar (Pyrimethamine) is an antimalarial agent, each tablet containing 500 mg N-(5,6-dimethoxy-4-pyrimidinyl) sulfanilamide (sulfadoxine) and 25 mg 2,4-diamino-5-(p-chlorophenyl)-6-ethylpyrimidine (pyrimethamine). Each tablet also contains cornstarch, gelatin, lactose, magnesium stearate and talc.
Fansidar (Pyrimethamine) Pharmacokinetics
The volume of distribution for sulfadoxine and pyrimethamine is 0.14 L/kg and 2.3 L/kg, respectively.
Patients taking 1 tablet a week (recommended adult dose for malaria prophylaxis) can be expected to have mean steady state plasma concentrations of about 0.15 mg/L for pyrimethamine after about four weeks and about 98 mg/L for sulfadoxine after about seven weeks. Plasma protein binding is about 90% for both pyrimethamine and sulfadoxine. Both pyrimethamine and sulfadoxine cross the placental barrier and pass into breast milk.
Fansidar (Pyrimethamine)
Fansidar (Pyrimethamine) Precautions
Oral Fansidar (Pyrimethamine) has not been evaluated for the treatment of cerebral malaria or other severe manifestations of complicated malaria, including hyperparasitemia, pulmonary edema or renal failure. Patients with severe malaria are not candidates for oral therapy. In the event of recrudescent . infections after treatment with Fansidar (Pyrimethamine) or failure of chemoprophylaxis with Fansidar (Pyrimethamine) , patients should be treated with a different blood schizonticide.
Fansidar (Pyrimethamine) should be given with caution to patients with impaired renal or hepatic function, to those with possible folate deficiency and to those with severe allergy or bronchial asthma. As with some sulfonamide drugs, in glucose-6-phosphate dehydrogenase-deficient individuals, hemolysis may occur. Urinalysis with microscopic examination and renal function tests should be performed during therapy of those patients who have impaired renal function. Excessive sun exposure should be avoided.
Patients should be warned that at the first appearance of a skin rash, they should stop use of Fansidar (Pyrimethamine) and seek medical attention immediately. Adequate fluid intake must be maintained in order to prevent crystalluria and stone formation.
Patients should also be warned that the appearance of sore throat, fever, arthralgia, cough, shortness of breath, pallor, purpura, jaundice or glossitis may be early indications of serious disorders which require prophylactic treatment to be stopped and medical treatment to be sought.
Females should be cautioned against becoming pregnant and should not breastfeed their infants during Fansidar (Pyrimethamine) therapy or prophylactic treatment.
Patients should be warned to keep Fansidar (Pyrimethamine) out of reach of children.
Patients also should be advised:
There have been reports which may indicate an increase in incidence and severity of adverse reactions when chloroquine is used with Fansidar (Pyrimethamine) as compared to the use of Fansidar (Pyrimethamine) alone. Fansidar (Pyrimethamine) is compatible with quinine and with antibiotics. However, antifolic drugs such as sulfonamides, trimethoprim, or trimethoprim-sulfamethoxazole combinations should not be used while the patient is receiving Fansidar (Pyrimethamine) for antimalarial prophylaxis. Fansidar (Pyrimethamine) has not been reported to interfere with antidiabetic agents.
If signs of folic acid deficiency develop, Fansidar (Pyrimethamine) should be discontinued. When recovery of depressed platelets or white blood cell counts in patients with drug-induced folic acid deficiency is too slow, folinic acid (leucovorin) may be administered in doses of 5 to 15 mg intramuscularly daily for 3 days or longer.
Fansidar (Pyrimethamine) Adverse Reactions
For completeness, all major reactions to sulfonamides and to pyrimethamine are included below, even though they may not have been reported with Fansidar (Pyrimethamine) (see and ).
Drug fever, chills, periarteritis nodosa and LE phenomenon have occurred.
The sulfonamides bear certain chemical similarities to some goitrogens, diuretics (acetazolamide and the thiazides), and oral hypoglycemic agents. Diuresis and hypoglycemia have occurred rarely in patients receiving sulfonamides. Cross-sensitivity may exist with these agents. Rats appear to be especially susceptible to the goitrogenic effects of sulfonamides, and long-term administration has produced thyroid malignancies in the species.
Fansidar (Pyrimethamine) Overdosage
Acute intoxication may be manifested by headache, nausea, anorexia, vomiting and central nervous system stimulation (including convulsions), followed by megaloblastic anemia, leukopenia, thrombocytopenia, glossitis and crystalluria. In acute intoxication, emesis and gastric lavage followed by purges may be of benefit. The patient should be adequately hydrated to prevent renal damage. The renal, hepatic, and hematopoietic systems should be monitored for at least 1 month after an overdosage. If the patient is having convulsions, the use of parenteral diazepam or a barbiturate is indicated. For depressed platelet or white blood cell counts, folinic acid (leucovorin) should be administered in a dosage of 5 mg to 15 mg intramuscularly daily for 3 days or longer.
Fansidar (Pyrimethamine) Dosage And Administration
The dosage should be swallowed whole, and not chewed, with plenty of fluids after a meal.
Fansidar (Pyrimethamine) How Supplied
Scored tablets, containing 500 mg sulfadoxine and 25 mg pyrimethamine — unit dose packages of 25 (NDC-0004-0161-03). Imprint on tablets: Fansidar (Pyrimethamine) ((ROCHE LOGO)) ROCHE.
Fansidar (Pyrimethamine)
