Pyrimethamine, sold under the brand name Daraprim among others, is a medication used with leucovorin (leucovorin is used to decrease side effects of pyrimethamine; it does not have intrinsic anti-parasitic activity) to treat the parasitic diseases toxoplasmosis and cystoisosporiasis. It is also used with dapsone as a second-line option to prevent Pneumocystis jiroveci pneumonia  in people with HIV/AIDS. It was previously used for malaria but is no longer recommended due to resistance. Pyrimethamine is taken by mouth.Common side effects include gastrointestinal upset, severe allergic reactions, and bone marrow suppression. It should not be used by people with folate deficiency that has resulted in anemia. There is concern that it may increase the risk of cancer. While occasionally used in pregnancy it is unclear if pyrimethamine is safe for the baby. Pyrimethamine is classified as a folic acid antagonist. It works by inhibiting folic acid metabolism and therefore the making of DNA.Pyrimethamine was discovered in 1952 and came into medical use in 1953. It is on the World Health Organizations List of Essential Medicines. It was approved as a generic in the United States in February 2020. Medical uses
Pyrimethamine is typically given with a sulfonamide and folinic acid.It is used for the treatment of toxoplasmosis, actinomycosis, and isosporiasis, and for the treatment and prevention of Pneumocystis jirovecii pneumonia. Toxoplasmosis
Pyrimethamine is also used in combination with sulfadiazine to treat active toxoplasmosis.
Marsupials have two uteri, each of which connect to a lateral vagina and which both use a third, middle "vagina" which functions as the birth canal. Marsupial embryos form a choriovitelline placenta (which can be thought of as something between a monotreme egg and a "true" placenta), in which the eggs yolk sac supplies a large part of the embryos nutrition but also attaches to the uterine wall and takes nutrients from the mothers bloodstream. However, bandicoots also have a rudimentary chorioallantoic placenta, similar to those of placental mammals. The fetus usually develops fully in placental mammals and only partially in marsupials including kangaroos and opossums. In marsupials the uterus forms as a duplex organ of two uteri. In monotremes (egg-laying mammals) such as the platypus, the uterus is duplex and rather than nurturing the embryo, secretes the shell around the egg. It is essentially identical with the shell gland of birds and reptiles, with which the uterus is homologous.In mammals, the four main forms of the uterus are: duplex, bipartite, bicornuate and simplex. Duplex
There are two wholly separate uteri, with one fallopian tube each. Found in marsupials (such as kangaroos, Tasmanian devils, opossums, etc. ), rodents (such as mice, rats, and guinea pigs), and lagomorpha (rabbits and hares). Bipartite
The two uteri are separate for most of their length, but share a single cervix. Found in ruminants (deer, moose, elk etc. ), hyraxes, cats, and horses. Bicornuate
The upper parts of the uterus remain separate, but the lower parts are fused into a single structure.