Amoxicillin is a penicillin-based antibiotic, meaning it is an antibacterial substance that kills certain bacteria by using the penicillin mold. Taken by mouth, it can be used in children for a variety of diseases, from the extremely common ear infection known as acute otitis media to the less common--but more severe--Lyme disease. Amoxicillin dosage depends on both the condition for which it is being prescribed and the age of the infant or child receiving the antibiotic. Individual circumstances vary, so always follow your doctor's or pharmacist's dosage instructions.
Acute Otitis Media: Ear Infection
Children 2 months to 6 years old should be given 80 to 90 mg of amoxicillin per kilogram of body weight per day, divided into two or three doses and taken for 10 days. For instance, if a 2-year-old child weighs 25 pounds, that is about 11 kg. A dose of 80 mg per kilogram per day means the total dosage per day is 880 mg. Divide the total dose into two equal doses of 440 mg each or three equal doses of 293 mg each.
For children older than 6 years, treat ear infections with 80 to 90 mg per kilogram per day divided into three doses taken for five or seven days, or up to 10 days if the infection is severe, as recommended by a doctor.
Ear, Nose and Throat Infection
Children up to 3 months old should be given no more than 30 mg of amoxicillin per kilogram of body weight per day, divided into two doses. Dosage for children 3 months and up weighing less than 40 kg--about 88 pounds--varies depending on the severity of infection. For mild or moderate infection, the dose is 25 mg per kilogram of body weight per day, divided into two equal doses. Another way to divide the dose is to give 20 mg per kilogram of body weight per day, divided into three doses. For children with severe infections, give 45 mg per kilogram of body weight per day; this should be divided into two doses.
Children who are older than 3 months and weigh more than 40 kg should take
500 mg twice daily or 250 mg three times a day for mild to moderate infection. In cases of more severe infection, the dose is increased to 875 mg twice daily or 500 mg three times a day. Note that as children get older and weigh more, the dose is no longer weight-dependent.
Streptococcal Pharyngitis: Strep Throat
Newborns and babies up to 12 weeks old should take no more than 30 mg per kilogram of body weight per day, divided into two doses. Children older than 12 weeks old may take 50 mg per kilogram of body weight, taken once daily for 10 days. The maximum dose is 1 g daily; note that the dose is not divided. This dosage of amoxicillin is used both to treat the strep throat and prevent rheumatic fever.
Pharyngitis/Tonsillitis: Inflammation of the Throat/Tonsils
Children 12 years and up may be given the extended release tablet of 775 mg, taken once daily for 10 days. Note that treatment should be completed even if symptoms have improved. The safety of the extended-release tablet has not yet been established in children under 12 years old and should not be used.
In the early stages of Lyme disease, when the disease has not yet spread to the joints and nerves, the suggested dose is 50 mg per kilogram of body weight per day, divided into three doses and taken for 14-21 days.
As the disease spreads to include the joints and nerves (Lyme arthritis), the dosage remains 50 mg per kilogram of body weight divided into three doses, but is taken for 28 days. The maximum amount taken should never be more than 1500 mg daily.