According to Drugs.com, the standard adult dosage for oral preparations of Demerol (meperidine hydrochloride) is between 50 and 150 milligrams, given every four to six hours. For children, the dose is calculated according to body weight, usually from 1.1 to 1.8 milligrams per kilogram up to the adult dosage.
As explained by WebMD, Demerol is a narcotic pain-relieving medication very similar to morphine. The exact amount given depends greatly upon the level of pain experienced by the patient and the exact medical condition that they are suffering from. If Demerol is used for an extensive period of time, it becomes less effective. Therefore, a different dosing strategy may be required to provide the same level of pain relief.