Doctors determine the best codeine dosage by determining dosage indications for that patient’s age and size, and by paying attention to patient response to the drug. For some individuals with certain medical conditions, it might not be the best drug choice, or a lower or higher dose could be needed. The patient’s use of any other medications might also affect dosage amounts, since codeine can interact with over 600 drugs.
The basic indication for codeine, whether given alone or with drugs like acetaminophen or phenergan, is 15-60 milligrams every four hours in adult patients. Doctors determine the best codeine dosage for children by calculating the kilogram weight of the child; one kilogram is equal to about 2.2 pounds. Each kilo means a dose of .5-1 milligrams of the drug, and a 30 pound (13.6 kg) child might take anywhere from 6-13 milligrams every four to six hours. There is an oral suspension of the drug that contains 12 milligrams in a teaspoon (5 ml), so a parent might be directed to give half that or the full dose every four hour to six hours.
Weight may also be a factor in determining codeine dosage for adults. A 120-pound (54.43 kilogram) woman might need a lower dose than a 250-pound (113.40 kilogram) man. Weight is not the only issue since individuals may metabolize or respond to drugs differently.
Part of skillful codeine dosage determination has to be based on checking in with patients and deciding how well the medicine is working. Doctors ideally start with the lowest dose they think will be effective, but if a patient does not get the desired relief, increasing the dose can make good sense. Alternately, a starting dose might cause over-sedation and unpleasant side effects. In this case, a decrease in dosage could be recommended.
Health issues influence the precise codeine dosage for individuals. In weighing health circumstances, doctors evaluate kidney or liver impairment, breathing issues, and allergy to codeine, among other things. They may decide a person’s health status contraindicates codeine. On the other hand, if a patient has a long history of opioid dependence, it’s unlikely a low dose will be effective, and doctors sometimes must exceed the dosage requirements in order to obtain pain relief for their patients.
The types of medications a patient takes affect codeine dosage. Since codeine depresses the central nervous system, it may work with other central nervous system depressants and create impaired breathing or too much sedation. Dosing is usually lowered or the drug may not be recommended in some patients who take one or more of the many drugs like antidepressants, barbiturates, seizure medications, neuroleptics, opioids, or tranquilizers that can interact with codeine. Alternately, some medications may impair codeine's ability to work, in which case a higher starting dose might be recommended to counter this.