Trypanosomiasis: Treatment, drugs that do not penetrate into the brain

• Suramin (Bayer 205®, Germanine®, Naphuride®, Moranyl®, Antrypol®). The compound was developed in 1920. It is best administered by slow intravenous infusion, as intramuscular administration (10% solution in distilled water) is very painful. Suramin is excreted extremely slowly by the body. This is important in allergy (exfoliative dermatitis). It can cause substantial proteinuria. When a test dose of 200 mg is tolerated well, the daily dose is 20 mg/kg (max. 1 g per dose; 1 g of the base = 10 ml of a 10% solution). This is to be repeated 5 times with intervals of a few days. There are several treatment regimens, such as 1 g on days 1, 3, 7, 14 and 21 (in adults) or on days 3, 10, 17, 24 and 31. Fever sometimes initially occurs due to lysis of trypanosomes. Suramin also kills Onchocerca volvulus filaria. Patients with active onchocerciasis can exhibit severe side effects to suramin. Suramin is frequently used for reducing the total number of trypanosomes, in order to reduce toxicity when Arsobal is administered.

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• Pentamidine was developed in 1941. It is less active than suramin and not active against T. b. rhodesiense. There are two water-soluble salts: pentamidine isethionate (Pentacarinat®), to be dissolved in sterile distilled water (not with physiological saline) and (hard to obtain): pentamidine dimethane sulphonate (Lomidine®), already dissolved as 4% base. Intramuscular injections are painful and are best given with the patient lying down since they cause a drop in blood pressure. If possible, slow IV administration is better. Rapid IV injection causes acute hypo­ten­sion and should be avoided. Hypoglycaemia can sometimes occur (release of insulin from the pancreas). This medicine is also used in pneumocystosis in AIDS patients. The dose is 3-4 mg base/kg/day for one week or every 2 days with a total of 10 injections (in adults). Alternatively, injections can be given on days 1, 3, 5, 13, 15 and 17. To calculate the dose: 1.7 mg salt is approximately equivalent to 1 mg of base. The usual dose for an adult person is between 150 and 300 mg per injection. Adrenalin and fluid are given intravenously if acute hypotension occurs.

Category: Medicine Notes