Low-dose zinc (5 mg or 10 mg) is as good as 20 mg for childhood diarrhea

Reference

Dhingra U, Kisenge R, Sudfield CR, et al. Lower-dose zinc for childhood diarrhea — a randomized, multicenter trial. N Engl J Med 2020;383(13):1231-1241.

Synopsis

Along with oral rehydration, 20 mg zinc once daily for 10 to 14 days is recommended for childhood diarrhea in low-resource countries to reduce stool volume and frequency, reduce the duration of diarrhea, increase weight gain, and replace zinc lost due to diarrhea. However, it also causes vomiting, which is of course counterproductive (number needed to treat to harm = approximately 20). These researchers in India and Tanzania identified young children, aged 6 months to 59 months, with acute watery diarrhea (3+ stools per day and less than 72 hours since onset) or acute dysentery (diarrhea with frank blood). Severely ill children were excluded, including those with severe malnutrition. They randomized 4500 children to receive 1 of 3 doses of zinc once daily: 5 mg, 10 mg, or 20 mg. There was no placebo group, as zinc 20 mg is considered an established effective therapy. Groups were balanced at the beginning of the study, and analysis was by intention to treat. The patients' mean age was 23 months, most had been sick for 25 hours to 48 hours, and only approximately 4% had dysentery. There was no difference among groups in diarrhea outcomes, but less vomiting over a 14-day period within 30 minutes of dosing with the lower doses: number needed to treat [NNT] = 18 for the 5-mg dose, and NNT = 27 for the 10-mg dose (compared with the 20-mg dose).