Normal somatic growth in children receiving low-dose prophylactic co-trimoxazole.

Co-trimoxazole is an effective antibacterial agent for the prophylaxis of urinary tract infection. Because experimental evidence raises the possibility that high-dose cotrimoxazole might interfere with normal somatic growth, the longitudinal growth and growth velocities were analysed in 114 girls receiving long-term, low-dose prophylactic cotrimoxazole. They were aged 2-12 years at the start of prophylaxis which was given in a daily dose of approximately 10 mg sulphamethoxazole (SMX) and 2 mg trimethoprim (TMP)/kg body weight for at least 6 months and for up to 6 years. There was no significant variation from normal in height or weight attained or in growth velocity overall in 114 girls, 51 of whom had vesico-ureteric reflux (VUR). No difference was found in growth velocity when periods of 6 months on or off prophylactic therapy were compared in 53 girls. Growth did not vary between cohorts of girls receiving co-trimoxazole prophylaxis for 2, 3 or 4 years and growth proceeded normally in the 51 girls with VU reflux. We have not found evidence that long-term, low-dose cotrimoxazole prophylaxis has any adverse effect upon somatic growth in girls with a previous urinary infection with or without vesico-ureteric reflux and who are otherwise healthy.