Acetaminophen/Tylenol/Paracetamol and many similar drugs are indeed dosed by weight in the hospital but as sibling comments say, this is likely too complex for

Acetaminophen/Tylenol/Paracetamol and many similar drugs are indeed dosed by weight in the hospital but as sibling comments say, this is likely too complex for parents. In the hospital, a formulary likely carries pills of different medication amounts, so a nurse can readily administer the correct dose - which a parent would struggle with.