Paresthesia suramin

Suramin is administered after a 200-mg intravenous test dose. Regimens that have been used include 1 g on days 1, 3, 7, 14, and 21 or 1 g each week for 5 weeks. Combination therapy with pentamidine may improve efficacy. Suramin can also be used for chemoprophylaxis against African trypanosomiasis. Adverse effects are common. Immediate reactions can include fatigue, nausea, vomiting, and, more rarely, seizures, shock, and death. Later reactions include fever, rash, headache, paresthesias, neuropathies, renal abnormalities including proteinuria, chronic diarrhea, hemolytic anemia, and agranulocytosis. 

The milder axonal polyneuropathy is the most common neurological adverse effect of suramin and causes distal paresthesia, reduced pain and vibration sensation in the feet, weak toe extensors, and absent ankle jerks this neuropathy is largely reversible. Milder neuropathies occurred in 50-70% of patients with plasma concentrations below 300 pg/ml, and severe motor neuropathy was rare in this category of patients. 

The more severe demyehnating neuropathies appear to be dose-related and occur when peak suramin plasma concentrations are maintained above 350 gg/ml the effective serum concentration in cancers is about 250 j,g/ml (SEDA-20, 283) (15,16). A Guillain-Barre-like polyradiculoneuropathy occurs in 10-20% of patients after 1-5 months of treatment, with a maximum at 2-9 weeks after the start of treatment. The first symptoms are distal limb and or facial paresthesia, followed by diffuse, symmetrical, proximal weakness and areflexia. About 25% of these patients eventually require ventilation. The CSF protein content may be raised. 

Suramin is the drug of choice for the early hemolymphatic stage of both Trypanosoma brucei gambiense and Trypanosoma brucei rhodesiense infections before nervous system invasion occurs [17 ]. The dose is 15-20 mg/kg/week, given intravenously, up to a maximum single dose of 1 g. Suramin, which is excreted by the kidneys, binds to plasma proteins and can persist in the circulation in low concentrations for as long as 3 months. A single course for an adult is usually 5 g, never to exceed 7 g. The primary adverse reactions are fever, rash, conjunctivitis, renal insufficiency, abdominal pain, paresthesia, and muscle pain. 

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