Analgesic effect of acetaminophen‐codeine combination in mice

Abstract The analgesic activity of acetaminophen and codeine phosphate was evaluated in mice (writhing test and hot‐plate test) after oral administration. When the two drugs were administered in combination, a potentiation was obtained; the analgesic effect is 1.8–6.6 times greater than when each drug is given alone. A central component for acetaminophen analgesia was confirmed.