Comparative tolerability of ampicillin, amoxicillin, and trimethoprim-sulfamethoxazole suspensions in children with otitis media.

The tolerabilities of ampicillin, amoxicillin, and trimethoprim-sulfamethoxazole (TMP-SMX) suspensions were evaluated in 263 children with otitis media. Because of watery stools, therapy was discontinued in 6 of 83 patients treated with ampicillin, in none of 89 patients treated with amoxicillin (P less than 0.01), and in 1 of 91 patients treated with TMP-SMX (P less than 0.03). Of the patients who completed the treatment courses, 13 recipients of ampicillin suffered loose or watery stools for 4 or more days, compared with 6 of the amoxicillin recipients (P less than 0.04) and 5 of the TMP-SMX recipients (P less than 0.02). Thus, ampicillin was clearly less well tolerated than either amoxicillin or TMP-SMX.