Pyrimethamine (Daraprim)

Pyrimethamine (Daraprim) is an approved antibiotic used in combination with a sulphonamide drug such as sulfadoxine for the treatment of toxoplasmosis. It also has anti-malarial activity, and is used in combination with sulfadoxine to prevent and to treat malaria.

Pyrimethamine has also been studied as a preventive treatment for Pneumocystis pneumonia (PCP) and toxoplasmosis in HIV-positive patients.1 However, it is now more commonly used in combination with other drugs, including dapsone, sulfadoxine or folinic acid as prophylaxis. For people who cannot tolerate cotrimoxazole (Septrin), it may also be used on its own or in combination with folinic acid or sulfadoxine to treat isosporiasis and prevent relapses.

Side-effects include bone marrow suppression and skin rashes. Folic acid in some vitamin supplements may hamper the effectiveness of pyrimethamine. Pyrimethamine levels can vary considerably from patient to patient, which may affect the drug’s efficacy and side-effects. Monitoring drug levels may be necessary.2 3

Pyrimethamine is best taken with food to minimise the risk of stomach upsets, loss of appetite and vomiting.

Pyrimethamine is a similar drug to trimethoprim, a component of cotrimoxazole. Since cotrimoxazole is commonly used to prevent PCP and other infections, there is a risk that its use can lead to resistance to pyrimethamine in the malaria parasite.4 Alternative drugs for the treatment of malaria may be needed in people who live in malaria endemic areas who are taking cotrimoxazole prophylaxis.

Pyrimethamine does not have any significant interactions with currently available protease inhibitors or non-nucleoside reverse transcriptase inhibitors (NNRTIs).

Pyrimethamine tablets are manufactured by GlaxoSmithKline. The combination of pyrimethamine and sulfadoxine in one tablet is manufactured by Roche under the trade name Fansidar. The combination of pyrimethamine and dapsone in one tablet is manufactured by GlaxoSmithKline under the tradename Maloprim.


  1. Klinker H et al. Pyrimethamine alone as prophylaxis for cerebral toxoplasmosis in patients with advanced HIV infection. Infection 24: 324-327, 1996
  2. Jacobson JM et al. Pyrimethamine pharmacokinetics in human immunodeficiency virus-positive patients seropositive for Toxoplasma gondii. Antimicrob Agents Chemother 40: 1360-1365, 1996
  3. Winstanley P et al. Marked variation in pyrimethamine disposition in AIDS patients treated for cerebral toxoplasmosis. J Antimicrob Chemother 36: 435-439, 1995
  4. Iyer JK et al. Plasmodium falciparum cross-resistance between trimethoprim and pyrimethamine. Lancet 358: 1066-1067, 2001

Community Consensus Statement on Access to HIV Treatment and its Use for Prevention

Together, we can make it happen

We can end HIV soon if people have equal access to HIV drugs as treatment and as PrEP, and have free choice over whether to take them.

Launched today, the Community Consensus Statement is a basic set of principles aimed at making sure that happens.

The Community Consensus Statement is a joint initiative of AVAC, EATG, MSMGF, GNP+, HIV i-Base, the International HIV/AIDS Alliance, ITPC and NAM/aidsmap

This content was checked for accuracy at the time it was written. It may have been superseded by more recent developments. NAM recommends checking whether this is the most current information when making decisions that may affect your health.

NAM’s information is intended to support, rather than replace, consultation with a healthcare professional. Talk to your doctor or another member of your healthcare team for advice tailored to your situation.