Does Naltrexone Show Up on a Drug Test?
Evidence-based answer reviewed against SAMHSA cutoffs and FDA assay documentation · Updated August 2026
Quick answer: No — not on any standard panel. Naltrexone is absent from routine 5-, 10-, and 12-panel employment drug tests. Never screened on standard panels; specialized adherence monitoring exists in treatment programs.
Which panels screen for it
| Panel | Naltrexone status |
|---|---|
| 5-Panel | ❌ Not included |
| 10-Panel | ❌ Not included |
| 12-Panel | ❌ Not included |
| DOT 5-panel (safety-sensitive) | ❌ Not included |
The details that matter
Naltrexone blocks opioid receptors rather than activating them — it's the opposite of an opioid in screening terms and appears nowhere on employment panels. Treatment programs may monitor levels to verify adherence to monthly injections.
If it IS detected, how long does it last?
| Test type | Typical Naltrexone detection window |
|---|---|
| Urine | any: 1–3 days (oral); injectable releases for weeks |
| Saliva (Mouth Swab) | any: ~1 day |
| Hair Follicles | rare |
| Blood | any: ~1 day |
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Does Naltrexone Show up in a Drug Test?
No — standard employment panels don't include Naltrexone. Only specialized orders reach it.
Does Naltrexone Show up in Drug Test?
No — standard employment panels don't include Naltrexone. Only specialized orders reach it.
How accurate are drug tests?
Lab-based immunoassay screens agree with confirmation testing ~97% of the time; confirmed GC–MS results are considered definitive. Home kits trade legal defensibility for convenience.
Do prescriptions count against me?
No — verified prescriptions report as negative through the Medical Review Officer. Declare medications at collection and answer the follow-up call.
Sources & further reading
- SAMHSA — Mandatory Guidelines for Federal Workplace Drug Testing Programs (cutoffs, MRO process)
- DOT — 49 CFR Part 40 procedures for transportation workplace testing
- Brahm NC et al., Mayo Clinic Proceedings 2008;83(1):66–76 — false-positive cross-reactivity reference
- FDA — drug-of-abuse test device labeling (detection window conventions)