From the FDA Drug Label
Pyrimethamine should be used with caution in patients with impaired renal or hepatic function or in patients with possible folate deficiency, such as individuals with malabsorption syndrome, alcoholism, or pregnancy, and those receiving therapy, such as phenytoin, affecting folate levels Pregnancy: Teratogenic Effects: Pregnancy Category C. Pyrimethamine has been shown to be teratogenic in rats when given in oral doses 2. 5 times the human dose for treatment of toxoplasmosis. Pyrimethamine should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus Concurrent administration of folinic acid is strongly recommended when used during pregnancy. Pyrimethamine may be used with sulfonamides, quinine and other antimalarials, and with other antibiotics
Sulfadoxine and pyrimethamine can be given to pregnant women for the treatment of uncomplicated malaria, but with caution. The potential benefit of using sulfadoxine and pyrimethamine must justify the potential risk to the fetus.
- Key considerations:
- Pyrimethamine is teratogenic in animal studies
- There are no adequate and well-controlled studies in pregnant women
- Concurrent administration of folinic acid is recommended when used during pregnancy 1
From the Research
Yes, sulfadoxine-pyrimethamine (SP) can be given to pregnant women for the treatment of uncomplicated malaria, particularly in areas where it remains effective. SP is actually one of the preferred antimalarials during pregnancy because of its established safety profile, as noted in a study published in 2007 2. The standard adult treatment dose is typically a single dose of 3 tablets (each containing 500mg sulfadoxine and 25mg pyrimethamine). SP is particularly important in malaria-endemic regions where it's used for intermittent preventive treatment in pregnancy (IPTp), administered at regular antenatal visits after the first trimester. However, it's essential to consider the following precautions:
- SP should not be given during the first trimester of pregnancy unless there are no suitable alternatives, due to potential risks associated with folate antagonist use during early pregnancy 2.
- SP should not be used in women taking cotrimoxazole prophylaxis due to increased risk of adverse reactions, as both drugs have similar mechanisms of action and can exacerbate each other's side effects 2.
- SP should also not be used in areas with high resistance to these medications, as this can lead to treatment failure and contribute to the development of further resistance.
The effectiveness of SP stems from its action against the folate synthesis pathway in the parasite, with sulfadoxine inhibiting dihydropteroate synthase and pyrimethamine inhibiting dihydrofolate reductase, thereby disrupting the parasite's ability to synthesize nucleic acids and proteins. A study from 2007 2 provides the most recent and highest quality evidence supporting the use of SP in pregnant women, highlighting its safety profile and efficacy in reducing the burden of malaria during pregnancy.
Some key points to consider when using SP in pregnant women include:
- The importance of administering SP after the first trimester, as part of IPTp, to minimize potential risks and maximize benefits 2.
- The need for careful monitoring of patients for signs of adverse reactions, particularly when used in combination with other medications 2.
- The potential for SP to be used in combination with other antimalarials, such as amodiaquine or artesunate, to improve treatment outcomes and reduce the risk of resistance, as demonstrated in studies from 2005 3 and 2002 4.
Overall, the use of SP in pregnant women for the treatment of uncomplicated malaria is supported by the available evidence, particularly when used in accordance with established guidelines and precautions.