A 35-year-old opioid-dependent patient is being considered for buprenorphine-naloxone (Suboxone) therapy. Why is naloxone included in the sublingual formulation?
- A Naloxone is inactive sublingually but will precipitate withdrawal if injected, acting as abuse deterrent ✓
- B Naloxone augments buprenorphine's analgesic effect
- C Naloxone is bioavailable sublingually and contributes to opioid blockade
- D Naloxone reduces buprenorphine's ceiling effect
Explanation
Naloxone has very poor sublingual/oral bioavailability—when taken as directed sublingually, it has minimal systemic absorption and does not interfere with buprenorphine's therapeutic opioid agonist effect. However, if the tablet is crushed and injected by someone attempting to abuse it, naloxone becomes fully bioavailable parenterally and precipitates acute opioid withdrawal by blocking/reversing opioid receptors. This serves as an abuse-deterrent mechanism. Buprenorphine alone (monotherapy) is used in pregnancy (to avoid precipitating withdrawal with injected naloxone if dosing error occurs) and in confirmed non-diversion settings.
Reference: Kaplan & Sadock's Synopsis of Psychiatry, 11th ed.
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Written and medically reviewed by the StethoPrep medical team.