A fixed-dose combination medication used primarily for the maintenance treatment of opioid dependence as part of a complete treatment plan, including counseling and psychosocial support. Buprenorphine is a partial opioid agonist that relieves opioid withdrawal symptoms and cravings, while naloxone is an opioid antagonist added to deter intravenous misuse. In the sublingual route, naloxone has minimal bioavailability, but if injected, it precipitates withdrawal in opioid-dependent individuals.
Adult: Induction must be done under supervision, starting when clear signs of moderate opioid withdrawal appear. Initial dose is often buprenorphine monotherapy. Maintenance: Target dose is typically 8-24 mg buprenorphine/2-6 mg naloxone per day, administered as a single daily sublingual dose. The 2mg/0.5mg strength is used for dose titration or as part of a divided dose regimen.
Note: Place tablet under the tongue until completely dissolved (takes 5-10 minutes). Do not chew, swallow, or inject. Do not eat or drink until tablet is fully dissolved. For doses requiring multiple tablets, place all tablets under tongue at once. If using 1/4 of a tablet, the remaining parts must be stored securely.
Buprenorphine binds with high affinity to mu-opioid receptors (MOR) as a partial agonist, providing sufficient agonist effect to suppress withdrawal and cravings but with a ceiling effect on respiratory depression, enhancing safety. Naloxone is a potent, competitive mu-opioid receptor antagonist with negligible sublingual bioavailability. When taken sublingually as intended, naloxone's effect is minimal. If the tablet is crushed and injected by an opioid-dependent individual, naloxone's systemic bioavailability becomes significant, displacing buprenorphine and other full agonists from receptors, precipitating acute withdrawal and deterring misuse.
Pregnancy: Category C: Use only if potential benefit justifies potential risk to the fetus. May cause neonatal withdrawal syndrome if used chronically. Buprenorphine monotherapy is often preferred in pregnancy. Requires specialist management.
Driving: May impair mental and/or physical abilities required for driving or operating machinery, especially during initiation and dose adjustment. Advise patients not to drive until they know how the medication affects them.
| Benzodiazepines (e.g., Alprazolam, Diazepam) | Profound sedation, respiratory depression, coma, death. | Major |
| Other CNS Depressants (Alcohol, Barbiturates, Sedative-hypnotics) | Additive CNS depression. | Major |
| CYP3A4 Inhibitors (e.g., Ketoconazole, Itraconazole, Ritonavir, Clarithromycin, Grapefruit juice) | Increased buprenorphine plasma levels, risk of toxicity. | Moderate |
| CYP3A4 Inducers (e.g., Rifampicin, Carbamazepine, Phenytoin, St. John's Wort) | Decreased buprenorphine plasma levels, risk of withdrawal. | Moderate |
| Monoamine Oxidase Inhibitors (MAOIs) | Risk of serotonin syndrome or opioid toxicity. | Major |
| Other Opioid Agonists (e.g., Morphine, Methadone, Fentanyl) | Buprenorphine may block effects of full agonists; can precipitate withdrawal. | Major |
| Anticholinergics | Increased risk of urinary retention and constipation. | Moderate |
| Antihypertensives | Potentiation of hypotensive effect. | Moderate |
Same composition (Buprenorphine (2mg) + Naloxone (0.5mg)), different brands: