Treatment of Trypansomiasis from CDC

Antitrypanosomal treatment is indicated for all persons diagnosed with African trypanosomiasis. Choice of therapy depends on the infecting subspecies of the parasite and on the disease stage. The first line drugs for both first and second stage disease are highly effective. Pentamidine, given by intravenous infusion over 2 hours or by intramuscular injection, is used to treat first stage T. b. gambiense infection. It is generally well tolerated, but adverse reactions of hypoglycemia, injection site pain, diarrhea, nausea and vomiting occur. Suramin is used to treat first stage T. b. rhodesiense. Suramin is also effective against T. b. gambiense, but it is not often used because severe reactions occur in persons who are co-infected with Onchocerca volvulus. Adverse reactions to suramin are frequent, but usually mild and reversible. These include drug rash, nephrotoxicity, and peripheral neuropathy. In rare instances, suramin administration results in a hypersensitivity reaction, and, for this reason, a small test dose is usually given prior to the full first dose.

Second stage T. b. gambiense is treated with eflornithine, which is given in 4 intravenous infusions daily for 14 days. Adverse effects of eflornithine include bone marrow suppression, gastrointestinal symptoms, and seizures. Eflornithine is highly effective, but the difficulty in administering 4 infusions daily in rural African facilities has led to the use of eflornithine (dosed less frequently) in combination with nifurtimox. The efficacy of the combination regimen appears to be at least as high as eflornithine monotherapy. Eflornithine is not effective against T. b. rhodesiense and it is not recommended for treating the East African form of the disease. Melarsoprol, an organoarsenic compound, is the only drug available for treating second stage T. b. rhodesiense. Adverse reactions to melarsoprol can be severe and life-threatening. An encephalopathic reaction occurs in 5-10% of patients with a case-fatality rate of approximately 50% when it occurs. Prednisolone is often given to patients who are being treated with melarsoprol to reduce the risk of encephalopathy. Other adverse reactions observed with melarsoprol include skin reactions, gastrointestinal upset, and peripheral neuropathy. Intravenous injections of melarsoprol are painful and can cause phlebitis. The drug is administered by use of lengthy and complicated dosing schedules, however, an abbreviated 10-day regimen appears promising.