My 4 year old weighs 45 lbs and is on the 250 concentration of amoxicillin 5ml 2 x a day is this enough ?

Standard dose: This is the standard dose for amoxicillin. A higher dose is used in some infections. Check in with your child's pediatrician if you have questions about the dosage.

Depends: The dosing depends both on their weight and the issue being treated. Lung and urine related illnesses have a great blood supply and the medicine reaches the area easily, so less is given than for an ear infection that may need a higher dose. If you will put what you are treating in your questions we can be more specific.