Melarsen in the treatment of trypanosoma gambiense infection in man

The results are given of further trials with melarsen in the treatment of cases of human sleeping sickness under field conditions in Northern and Eastern Nigeria. Using treatment courses with an individual dosage not in excess of 20 mg. per kg., the incidence of severe toxic effects was only 2.8 per cent. It is considered that 20 mg. per kg. is the maximum safe dose for field use and should not be exceeded. A course of 12 injections each at 5-day intervals is advocated to reduce the possibility of evoking melarsen resistance. Toxic effects were no more common with this course than with shorter régimes. In early cases treated with melarsen the cure rate is excellent, as it is with the standard drugs which are cheaper and even less toxic. In the treatment of advanced cases melarsen gives considerably better results than standard courses of treatment which include tryparsamide. In the present series the cure rate following melarsen varied from 56 per cent. to 71 per cent., depending on the dosage employed. Of patients who had relapsed following other treatment, 70 per cent. of intermediate and 38 per cent. of advanced cases were cured following a course of melarsen. The present trials indicate that melarsen has a valuable place in the chemotherapy of late and relapsed cases under field conditions where its comparatively low toxicity in the prescribed dosage and its ease of administration make it a safe drug in the hands of trained assistants. However, in view of the possibility of acquired resistance to melarsen, it should be given only under conditions where adequate dosage and regular attendance of the patient can be guaranteed.