Description
PHARMACOLOGY
Sulfadoxine and Pyrimethamine combination acts by reciprocal potentiating of its two components achieved via a sequential blockade of two enzymes involved in the biosynthesis of folic acid in the parasites. Sulfadoxine plus Pyrimethamine is effective against strains of Plasmodium falciparum that are resistant to chloroquine.
Both Sulfadoxine and Pyrimethamine are absorbed orally and are excreted mainly by the kidneys. Following a single tablet administration, sulfadoxine peak plasma concentrations of 51 to 76 mcg/mL are achieved in 2.5 to 6 hours and the Pyrimethamine peak plasma concentrations of 0.13 to 0.4 mxg/mL are achieved in 1.5 to 8 hours. The mean elimination half life of Sulfadoxine is 169 hours whereas that of Pyrimethamine is 111 hours.
INDICATIONS
Treatment of P. falciparum malaria for those patients in whom chloroquine resistance is suspected.
CONTRA-INDICATIONS
Repeated use of Sulfadoxine plus Pyrimethamine is contraindicated in patients with severe renal insufficiency, marked liver parenchyma damage or blood dyscrasias.
Hypersensitivity to Pyrimethamine and/or Sulfonamides
Patients with documented megaloblastic anemia due for folate deficiency
Infants less than 2 months of age
Pregnancy at term and during the nursing period.
PRECAUTIONS/WARNINGS
Sulfadoxine plus 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 brounchial asthma.
Patients should be warned that at the first appearance of a skin rash, they should stop use of Sulfadoxine plus Pyrimethamine and seek immediate medical attention.
INTERACTIONS
There have been reports that incidence and severity of adverse effects may be increased by co-administering Chloroquine with Sulfadoxine plus Pyrimethamine.
Antifolic drugs such as Co-trimoxazole should not be used while the patients is receiving the combination of antimalarial prophylaxis
In Pregnancy and Lactation:
There are no adequate or wellcontrolled studies in pregnant women.
Since Sulfonamides are excreted in the human breast milk, the said combination is not recommended to nursing mothers.
DOSAGE & ADMINISTRATION
(a) Treatment of acute attack of malaria
A single dose of the following number of Sulfadoxine plus Pyrimethamine combination is used in sequence with quinine or alone
Adults 2-3 tablets
Children
9-14 years 2 tablets
4-8 years 1 tablet
under 4 years ½ tablet
(b) In Prophylaxis, the above dosage to be taken every two weeks.
STORAGE/HANDLING RECOMMENDATIONS
Store in a cool dry place and keep away from the reach of children. Protect from light.
