how long does it take for infant tylenol to work

Infant Tylenol (acetaminophen) usually takes about 20 minutes to up to an hour to start working. Most babies feel the effects within 30 to 45 minutes after oral administration. The medication works as a pain reliever and fever reducer, and the full effect can be expected around this timeframe. It is important to dose according to the infant's weight and not to give more than five doses within 24 hours. If the infant is younger than 3 months with a fever of 100.4°F or higher, or older with a persistent fever or pain, medical advice should be sought.