Can amoxicillin treat strep throat in an infant? what would be the dosage for a five month old?

Depends on weight: If a throat culture was performed and the baby has strep, Amoxicillin can treat it. The dosage would be calculated based on the baby's weight.

No treatment : We don't treat strep throat in infants. It's self limited and doesn't give any complications. Due to the above infants shouldn't be tested for strep.

Infant strep throat: Strep pharyngitis is less common in children under 1 year, but does occur and can cause disease. If strep pharyngitis is diagnosed in an infant 6-12 months of age, it should be treated. Amoxicillin, in a dose of 40-50 mg/kg is a good choice (assuming there are no drug allergies).

Not common: Under a year of age , but can happen. Should have a strep test to confirm. The doctor will calculate the dose based on weight(@ 40mg/kg.