Therapeutic Switch to Buprenorphine/Naloxone from Buprenorphine Alone

Abstract

Pharmacological therapy has an important place in the management of opioid dependence. Methadone has been the mainstay of therapy but has a number of limitations. Buprenorphine monotherapy is another option, but misuse and diversion can have negative consequences. The opioid receptor antagonist, naloxone, has been added to buprenorphine to create a combination product with a reduced potential for misuse and diversion. This study evaluated the use of buprenorphine/naloxone for 24 weeks as a pharmacological management of opioid-dependent patients after therapeutic switch from buprenorphine alone. Patients (n = 43) received sublingual tablets of buprenorphine/naloxone. The buprenorphine dose was 2-24 mg (mean 16). Patients saw a physician, including an interview using a structured data sheet, and had counselling each week. Assessments were performed at week 2 (period 1), week 6 (period 2), week 16 (period 3) and week 24 (period 4). Laboratory immunoenzymatic testing was performed weekly to detect drugs in the urine. The management of withdrawal symptoms was rated as 'satisfactory' by 67% of patients during period 1 and 91% during period 4. The majority of patients was highly satisfied with therapy and considered that buprenorphine/naloxone provided good control of cravings. Two patients dropped out of therapy, but all others continued to receive buprenorphine throughout the study. Approximately 50% of patients stated that they disliked the sensory properties (taste, colour, odour and feel) of buprenorphine/naloxone. Adverse effects were as would be expected on the basis of the mechanism of action of buprenorphine (i.e. opioid-induced constipation) and for patients undergoing drug withdrawal. Only 2% of patients attempted the intravenous misuse of buprenorphine/naloxone, none of whom experienced any gratifying effects. Opioid-dependent patients maintained on buprenorphine monotherapy can be safely switched to a sublingual buprenorphine/naloxone tablet without any loss of treatment effectiveness. Buprenorphine/naloxone can be administered in an outpatient or primary care setting, and effectively controls cravings and withdrawal symptoms. Patient satisfaction was high, making retention in treatment more likely.