Pyrimethamine / Sulfadoxine Dosage

Applies to the following strengths: 25 mg-500 mg

Usual Adult Dose for Malaria

2 or 3 tablets taken orally as a single dose, following a 3 to 7 day course of quinine (650 mg every 8 hours).

Usual Adult Dose for Malaria Prophylaxis

1 tablet orally every week beginning 1 or 2 days before departure to an endemic area; continue administration during the stay and for 4 to 6 weeks after returning.

Alternative: 2 tablets every 2 weeks beginning 1 or 2 days before departure to an endemic area; continue administration during the stay and for 4 to 6 weeks after returning.

Usual Adult Dose for Pneumocystis Pneumonia Prophylaxis

1 tablet (25/500 mg) orally once or twice a week.

Pyrimethamine-sulfadoxine is generally not recommended for PCP prophylaxis unless trimethoprim-sulfamethoxazole, pentamidine, dapsone/pyrimethamine/leucovorin, atovaquone, or dapsone cannot be used.

Usual Pediatric Dose for Malaria

>2 months:
5-10 kg: One-half tablet orally one time
11-20 kg: 1 tablet orally one time
21-30 kg: 1.5 tablet orally one time
31-45 kg: 2 tablets orally one time
>45 kg: 3 tablets orally one time

A 3 to 7-day course of quinine should precede the pyrimethamine-sulfadoxine dose.

Usual Pediatric Dose for Malaria Prophylaxis

> 2 months:
5-10 kg: 1/4 (0.25) tablet orally once a week
11-20 kg: 1/2 (0.5) tablet orally once a week
21-30 kg: 3/4 (0.75) tablet orally once a week
31-45 kg: 1 tablet orally once a week
>45 kg: 1.5 tablet orally once a week

Begin 1 or 2 days before departure to an endemic area; continue administration during the stay and for 4 to 6 weeks after returning.

Renal Dose Adjustments

Caution is recommended in patients with renal impairment. Renal function tests and urinalysis are recommended during therapy.

Repeated prophylactic use is contraindicated in patients with renal failure.

Liver Dose Adjustments

Caution is recommended in patients with hepatic impairment. Repeated prophylactic use is contraindicated in patients with hepatic failure.

Precautions

Severe side effects including fatal Stevens-Johnson syndrome and toxic epidermal necrolysis have occurred in patients taking pyrimethamine-sulfadoxine. Discontinue this medication at the first sign of a skin rash or if a decrease in formed blood elements is noted, or upon the occurrence of active bacterial or fungal infections.

Sulfadoxine-pyrimethamine is contraindicated in patients with blood dyscrasias, megaloblastic anemia due to folate deficiency, and in infants less than 2 months of age..

Discontinue if folic acid deficiency develops.

Prophylaxis should not be continued for more than 2 years.

Dialysis

Caution is recommended in patients with renal impairment. Repeated prophylactic use is contraindicated in patients with renal failure.

Other Comments

Current CDC recommendations should be consulted when initiating malaria prophylaxis or therapy.

The dose should be swallowed whole, not chewed, with plenty of fluids after a meal.