Abuse and misuse of pharmacological
therapies represent major challenges in the healthcare system, particularly in patients receiving long-acting
opioid drugs for the treatment of
heroin or
opioid addiction. The partial
mu-opioid receptor agonist
buprenorphine is used to treat
opioid dependence, but diversion and misuse may occur. The sublingual combination formulation of
buprenorphine and the
opioid receptor antagonist naloxone (buprenorphine/naxolone) is associated with a reduced abuse potential, and has been shown to have promising efficacy for the treatment of
opioid dependence. This observational study assessed the safety and efficacy of sublingual
buprenorphine/naloxone combination therapy in patients with
opioid dependence after therapeutic switch from
buprenorphine monotherapy. A total of 94 patients being treated with
buprenorphine monotherapy (average dose 8 mg/day; mean
duration of therapy 840 days) were switched to
buprenorphine/naloxone combination therapy. Patients were asked to rate their level of satisfaction with
buprenorphine/naloxone combination treatment with respect to the management of
withdrawal symptoms, and urinary toxicology tests were carried out before and 14 days after switching to combination
therapy. Within 3 months, 75/94 patients (80%) previously treated with
buprenorphine monotherapy had switched to sublingual
buprenorphine/naloxone combination treatment (average dose
buprenorphine 8 mg). Among patients receiving combination treatment for >3 months, 83% were receiving medication either weekly or fortnightly, based on the results of toxicological testing. A reduction in positive urinary toxicology tests was observed in patients within two weeks after being switched to combination treatment (before switch: 28, 9 and 2 positive tests for
heroin,
cocaine and
heroin +
cocaine, respectively vs 11, 3 and 1 after switch) and a total of 64 patients of the 75 who switched to combination
therapy (85%) were satisfied with the management of
withdrawal symptoms during
buprenorphine/naloxone treatment. Few adverse events were reported and no patients dropped out of treatment. This study shows that switching from
buprenorphine monotherapy to sublingual
buprenorphine/naloxone combination therapy is effective and well tolerated, and associated with good control of
withdrawal symptoms in the majority of patients. In addition, combination
therapy reduced
illicit drug use (based on negative urinary toxicology texts) and allowed the time between
clinic visits to be increased.