Post-transplantation analgesic dependence in patients who formerly suffered from analgesic neophropathy.

Twenty-two patients with functioning grafts who originally developed renal failure due to analgesic nephropathy ("analgesic" group), and 84 patients with various other causes of renal failure ("non-analgesic" group) were studied over one year to assess the extent of analgesic use and abuse. On each occasion that one of these patients reported to hospital a urine sample was collected and analyzed for N-acetylparaminophenol (NAPA). Of the "analgesic" group of patients, 14% had consistently negative urine samples while 41% showed NAPA in more than half the urines collected. In the "non-analgesic" group 29% of patients had entirely negative urine tests, and in only 7% were more than half of the urines NAPA-positive. Patients in the "non-analgesic" group readily admitted taking anaglesics at frequencies compatible with the observed number of positive tests. This contrasted with the "analgesic" group in which 14 of 19 patients with NAPA-positive urines denied analgesic intake. This is considered to be a guilt manifestation in patients who have developed a psychological dependence on analgesics and have recidivated with full knowledge of the possible harm these drugs may inflict on their grafts.