Individual Medication Effectiveness Tests (IMETs) to assess the efficacy of gabapentin in individual patients with chronic neuropathic pain.

This single patient (n of 1) IMET is a randomised, double-blind, cross-over comparison of gabapentin and placebo within an individual patient. We will do an initial open label trial to see if gabapentin is effective, and for dose finding. Once the dose has been decided (see medication section), we will use two week treatment periods, with measurement in the second week, allowing for wash out. There will be 3 pairs of 2 week treatment periods, making a total of twelve weeks. The order of drugs in each cycle will be determined by random allocation. The choice of initial therapy will be balanced in blocks of four, to ensure that equivalent numbers start the IMET on each of the two drugs. Patients and practitioners will all be blinded to which treatment the patients are taking. Product information about gabapentin will be provided to the patient at the beginning of the study. The patient will keep careful track of their symptoms by recording them in a special diary. If at any time during the study the patient feels worse, that treatment period can be terminated, and they can go on to the next treatment period. Upon the completion of the study, the timing of the active treatment will be revealed. After looking at the symptoms recorded, the doctor and patient decide together whether gabapentin was of greater benefit than placebo. If the patient chooses, they can then continue on the drug, confident that it is effective.