Efficacy of Sulphadoxine and Pyrimethamine, Doxycycline and their combination in the treatment of chloroquine resistant Falciparum Malaria

OBJECTIVE: The present in vivo study evaluates the efficacy of sulphadoxine/pyrimethamine, doxycycline and their combination in the treatment of Sudanese patients infected by chloroquine resistant falciparum malaria.

METHODS: Febrile patients with positive blood smears of Plasmodium falciparum were given chloroquine 25mg-base/kg body weight and followed up for 3 days. Patients with recrudescence due to chloroquine resistance were readmitted for test treatment. Using simple number randomization patients were divided into groups, A, B and C. These were treated with doxycycline, sulphadoxine/ pyrimethamine and a combination therapy of sulphadoxine/pyrimethamine plus doxycycline. Doxycycline was initially administered as a single dose of 200mg followed by 100mg daily for 6 days whereas sulphadoxine/pyrimethamine was given as a single dose of sulphadoxine 1500mg and pyrimethamine 75mg. Patients of group C received the combination therapy of sulphadoxine/pyrimethamine and doxycycline. Clinical observations and examination of blood films were carried out for each patient daily for 6 days and thereafter weekly for 4 weeks.

RESULTS: A high level of chloroquine resistance (75%) was documented amongst 280 patients (age 15-53 years) visiting Omdurman Hospital of Endemic Diseases during 1996-1998. The study demonstrated that only 46% and 78% of the patients were cured after 4 days of treatment by doxycycline and sulphadoxine/pyrimethamine. Patients treated with sulphadoxine/pyrimethamine in combination with doxycycline had a cure rate of 90% and 100% after 3-4 days of treatment, a single recrudescent case was detected on day 6. No relapses occurred during the follow up period. All patients were successfully treated by all regimens with the exception of one case treated by doxycycline. All treatments were well tolerated but a few cases had complaints of nausea.

CONCLUSION: The combination therapy of doxycycline/sulphadoxine/pyrimethamine appeared to be significantly effective in the treatment of patients with chloroquine resistant falciparum malaria without causing any serious side effects. Such a combination regimen has the advantages of being available at a reasonable cost and less prone to development of resistance.