Penicillin V has a short half-life and administering it only twice daily may lead to a greater rate of failures.
In a meta-analysis of 35 randomized, controlled trials comparing penicillins, primarily penicillin V, with cephalosporins, the bacterial cure rate with penicillins declined from 83.4% for trials conducted in the 1970s to 79.4% for those conducted in the 1990s (FIGURE 4).
(43) Similarly, in another investigator-blinded study of pediatric patients aged 1 to 12 years, cefdinir administered at a dose of 7 mg/kg twice daily for 5 days produced higher eradication rates measured 4 to 10 days after completion of treatment than penicillin V 10 mg/kg 4 times daily for 10 days (89.7% vs 71.8%; P<0.001).