Optimum management of postoperative pain.

After surgery, patients try to minimise discomfort by various manoeuvres including change of posture, immobilisation of injured areas and use of analgesic drugs. The characteristic finding with drug use, revealed by permitting patients to titrate themselves with analgesic from a machine, is that the interindividual dosing rate has a wide range around the mean. Some patients will require almost no drug; others will need 2 to 3 times the mean dosing rate. Wide differences are also seen in the rate at which the need for drug declines. None of these parameters can be predicted with any useful degree of accuracy in the individual patient. Regimens which rigidly fix dosage in advance, which limit dosage rate through an often ill-founded fear of other pharmacological effects, or which cannot guarantee access of the patient to the drug, are unable to cope with such variation. Dose adjustment through feedback of effect from the patient is essential to combat this uncertainty, and is the prime determinant of optimum therapeutic efficacy. Although risk could be increased as well as benefit, experience shows that almost all patients may be trusted with control of their own pain relief without detrimental sequelae. Many of the newer therapeutic regimens represent differing attempts at the trade-off between the individualization (and consequent increased complexity) required for optimum therapeutic efficacy and the rigidity (and consequent increased simplicity) needed for routine implementation. Optimum management results from using a regimen which strikes the right balance for the clinical circumstances of the patient and prescriber.