Artesunate (AS) is a medication used to treat malaria. The intravenous form is preferred to quinidine for severe malaria. Often it is used as part of combination therapy, such as artesunate plus mefloquine. It is not used for the prevention of malaria. Artesunate can be given by injection into a vein, injection into a muscle, by mouth, and by rectum. Artesunate (AS) is a medication used to treat malaria. The intravenous form is preferred to quinidine for severe malaria. Often it is used as part of combination therapy, such as artesunate plus mefloquine. It is not used for the prevention of malaria. Artesunate can be given by injection into a vein, injection into a muscle, by mouth, and by rectum. Artesunate is generally well tolerated. Side effects may include a slow heartbeat, allergic reaction, dizziness, and low white blood cell levels. During pregnancy it appears to be a safer option, even though animal studies have found harm to the baby. Use is likely okay during breastfeeding. It is in the artemisinin class of medication. Artesunate is on the World Health Organization's List of Essential Medicines, the most effective and safe medicines needed in a health system. The wholesale cost in the developing world is US$2.09 to US$2.57 a dose. It is not commercially available in the United States; however, can be gotten from the Centers for Disease Control. It was originally made from the sweet wormwood plant. Artesunate is the first line treatment for children or adults with severe malaria, usually in combination with another antimalarial drug. There is moderate-quality evidence that treatment with artesunate plus mefloquine is superior to treatment with artesunate plus amodiaquine or artesunate plus sulfadoxine-pyrimethamine. Artemisinin-based combination therapy may be used by mouth in persons that can tolerate it after 24 hours by injection. In facilities where long-term care is not appropriate, initial treatment with artesunate may be given as a single intramuscular injection or by rectal route (children < 6 years) prior to transferring care to a higher level facility. Artesunate is preferred over parenteral quinine for severe malaria treatment. Artesunate was shown to prevent more deaths from severe malaria than quinine in two large multicentre randomized controlled trials from Africa and Asia. A subsequent systematic review of seven randomized controlled trials found this improvement in survival rates to be consistent across all trials. Artesunate is also used to treat less severe forms of malaria when it can be given orally. It has activity against P. ovale, P. malariae, and severe P. knowlesi. Artesunate + sulfadoxine/pyrimethamine for treatment of P. vivax is not recommended due to high rates of resistance. While artesunate is used primarily as treatment for malaria, there is some evidence that it may also have some beneficial effects in Schistosoma haematobium infection, but has not been evaluated in large randomized trials. Although not FDA-approved for use in the United States, artesunate is used as the treatment of choice for severe malaria by the World Health Organization (WHO) over quinidine.