Melarsoprol is a medication used for the treatment of sleeping sickness (African trypanosomiasis). It is specifically used for second-stage disease caused by Trypanosoma brucei rhodesiense when the central nervous system is involved. For Trypanosoma brucei gambiense, the medication eflornithine is usually preferred. It is effective in about 95% of people. It is given by injection into a vein.Chagas disease: nitroimidazole (Benznidazole#)Pentavalent antimonials (Meglumine antimoniate#, Sodium stibogluconate) Melarsoprol is a medication used for the treatment of sleeping sickness (African trypanosomiasis). It is specifically used for second-stage disease caused by Trypanosoma brucei rhodesiense when the central nervous system is involved. For Trypanosoma brucei gambiense, the medication eflornithine is usually preferred. It is effective in about 95% of people. It is given by injection into a vein. Melarsoprol has a high number of side effects. Common side effects include brain dysfunction, numbness, rashes, and kidney and liver problems. About 1-5% of people die during treatment. In those with glucose-6-phosphate dehydrogenase (G6PD) deficiency, red blood cell breakdown may occur. It has not been studied in pregnancy. It works by blocking pyruvate kinase, an enzyme required for the parasite to make adenosine triphosphate. Melarsoprol has been used medically since 1949. It is on the World Health Organization's List of Essential Medicines, the most effective and safe medicines needed in a health system. In regions of the world where the disease is common, melarsoprol is provided for free by the World Health Organization. It is not commercially available in Canada or the United States. In the United States, it may be obtained from the Centers for Disease Control and Prevention, while in Canada it is available from Health Canada. People diagnosed with trypanosome-caused disease should be treated with an anti-trypanosomal. Treatment is based on stage, 1 or 2, and parasite,T. b. rhodesiense or T. b. gambiense. In stage 1 disease, trypanosomes are present only in the peripheral circulation. In stage 2 disease, trypanosomes have crossed the blood brain barrier and are present in the central nervous system. The following are considerable treatment options: Melarsoprol is a treatment used during the second stage of the disease. So far, it is the only treatment available for late-stage T. b. rhodesiense. Due to high toxicity, melarsoprol is reserved only for the most dangerous cases. Other agents associated with lower toxicity levels are used during stage 1 of the disease. The approval of the nifurtimox-eflornithine combination therapy (NECT) in 2009 for the treatment of T. b. gambiense limited the use of melarsoprol in the treatment of second-stage T. b. rhodesiense. Failure rates of 27% in certain African countries have been reported. This was caused by both drug resistance and additional mechanisms that have not yet been elucidated. Resistance is likely due to transport problems associated with the P2 transporter, an adenine-adenosine transporter. Resistance can occur with point mutations within this transporter. Resistance has been present since the 1970s. Although melarsoprol cures about 96% of people with late stage disease, its toxicity limits its use. About 1-5% of people die during treatment. As a toxic organic compound of arsenic, melarsoprol is a dangerous treatment that is typically only administered by injection under the supervision of a licensed physician. Notable side effects are similar to arsenic poisoning. Among clinicians, it is colloquially referred to as 'arsenic in antifreeze'. Severe and life-threatening adverse reactions are associated with melarsoprol. It is known to cause a range of side effects including convulsions, fever, loss of consciousness, rashes, bloody stools, nausea and vomiting. In approximately 5-10% of cases, it causes encephalopathy. Of those, about 50% die due to encephalopathy-related adverse reactions. Additional potentially serious side effects of melarsoprol include damage to the heart, presence of albumin in the urine that could be associated with kidney damage, and an increase in blood pressure.