The effect of sodium bicarbonate on a single dose of diethylcarbamazine therapy in patients with bancroftian filariasis in Kenya

Abstract

An attempt was made to examine the effect of a combination of diethylcarbamazine citrate (DEC-C) and sodium bicarbonate (NaHCO 3) on the pharmacokinetics of diethylcarbamazine (DEC), side-reactions and reduction of the microfilarial density of patients with Wuchereria bancrofti infection at a hospital in Nairobi, Kenya. The microfilariae carriers received DEC-C at 6 mg/kg or 3 mg/kg with or without NaHCO 3 at 75 mg/kg body weight. The patients treated with a combination of drugs showed alkaline urine for 4 h post-treatment, while patients treated with DEC-C alone showed acidic urine. Although no significant difference was detected in the DEC half-life value and other pharmacokinetic parameters between patients treated with DEC-C (6 mg/kg) plus NaHCO 3 (75 mg/kg) and those treated with DEC-C (6 mg/kg) alone, the general tendency was that in patients receiving NaHCO 3 the first-order elimination rate constant decreased and serum elimination half-life and area under the serum concentration-time curve values increased. There was a significant difference between the mean values of the first-order absorption rate constant, the first-order elimination rate constant, and the time to maximum serum concentrations for the patients receiving DEC-C at 3 mg/kg plus NaHCO 3 at 75 mg/kg and those for the group receiving DEC-C at 6 mg/kg alone. There was no difference in frequency and severity of the side-reactions between patients receiving DEC-C at 6 mg/kg plus NaHCO 3 at 75 mg/kg, DEC-C at 3 mg/kg plus NaHCO 3 at 75 mg/kg, and DEC-C at 6 mg/kg alone. During the initial 5 days post-treatment, there was no significant difference in reduction of microfilarial density among these three groups. In the field, an attempt was made to examine the possibility of increased antifilarial effect using a combination of DEC-C and NaHCO 3. The patients were examined for microfilariae, given DEC-C at 6 mg/kg with or without NaHCO 3 at 75 mg/kg, and examined for microfilariae again 1 year later. Although the cure rate was the same among the groups, the percentage reduction in microfilarial density of the patients receiving DEC-C plus NaHCO 3 was significantly greater than those of patients receiving DEC-C alone. A combination of DEC-C with NaHCO 3 will be of practical value in a single dose of DEC-C for the mass-treatment of bancroftian filariasis.