Pyrimethamine, sold under the trade name Daraprim, is one of the folic acid antagonists that is used as an antimalarial or with a sulfonamide to treat toxoplasmosis. In addition it was approved in Chemoprophylaxis of Malaria. However, resistance to pyrimethamine is prevalent worldwide. It is not suitable as a prophylactic agent for travelers to most areas. Pyrimethamine is well absorbed with peak levels occurring between 2 to 6 hours following administration. It is eliminated slowly and has a plasma half-life of approximately 96 hours. Pyrimethamine is 87% bound to human plasma proteins. Pyrimethamine acts by selectively inhibiting malarial dihydrofolate reductase-thymidylate synthase and the rationale for its therapeutic action is based on the differential requirement between host and parasite for nucleic acid precursors involved in growth. This activity is highly selective against plasmodia and Toxoplasma gondii. Pyrimethamine possesses blood schizonticidal and some tissue schizonticidal activity against malaria parasites of humans. The action of pyrimethamine against Toxoplasma gondii is greatly enhanced when used in conjunction with sulfonamides.

Pyrimethamine, sold under the trade name Daraprim, is one of the folic acid antagonists that is used as an antimalarial or with a sulfonamide to treat toxoplasmosis. In addition it was approved in Chemoprophylaxis of Malaria. However, resistance to pyrimethamine is prevalent worldwide. It is not suitable as a prophylactic agent for travelers to most areas. Pyrimethamine is well absorbed with peak levels occurring between 2 to 6 hours following administration. It is eliminated slowly and has a plasma half-life of approximately 96 hours. Pyrimethamine is 87% bound to human plasma proteins. Pyrimethamine acts by selectively inhibiting malarial dihydrofolate reductase-thymidylate synthase and the rationale for its therapeutic action is based on the differential requirement between host and parasite for nucleic acid precursors involved in growth. This activity is highly selective against plasmodia and Toxoplasma gondii. Pyrimethamine possesses blood schizonticidal and some tissue schizonticidal activity against malaria parasites of humans. The action of pyrimethamine against Toxoplasma gondii is greatly enhanced when used in conjunction with sulfonamides.

Norharman or beta-carboline (9H-pyrido[3,4-b]indole) is a neuroactive alkaloid first isolated from Peganum harmala L. It is implicated in a number of human diseases including Parkinson's disease, tremor, addiction and cancer. Norharman formed endogenously but external sources have been identified (among others fried meat and fish, meat extracts, alcoholic drinks, coffee brews, tobacco smoke). It inhibits monoamine oxidase and indoleamine 2,3-dioxygenase. In addition norharman binds with high affinity to imidazoline I2B receptors. Plasma norharman levels are elevated in chronic alcoholics and Parkinson's disease patients.