Naltrexone Limited data

Limited data

Sparse data. Doses and effects may be unreliable or untested.

• 2 corroborating sources
• partial dose data
• toxicity data
• dose data not in PW/TripSit (unverifiable)

Summary

Naltrexone (ReVia, Vivitrol) is a long-acting opioid antagonist used to support recovery from opioid and alcohol dependence: a daily 50 mg tablet or a monthly 380 mg injection that occupies opioid receptors so opioids produce little or no effect. It has no opioid effects of its own, no euphoria, and no dependence or diversion potential — it is not aversive therapy and causes no disulfiram-style reaction. Two warnings matter more than everything else on this page: starting it with opioids still in your system (kratom included) precipitates withdrawal severe enough to require hospitalization — the labels require a minimum of 7–10 opioid-free days, and 10–14 after methadone or buprenorphine — and, in the other direction, the blockade resets opioid tolerance: using after a missed dose or after stopping treatment means a formerly normal dose can now be a fatal overdose, and trying to force through the blockade with large opioid doses is exactly how those deaths happen.

Dose Information source varies by route

Dose basis. Treatment doses from the FDA labels — naltrexone has no recreational dose or effect. Oral: a 25 mg test dose, then 50 mg once daily (the label also sanctions 100 mg every other day or 150 mg every third day). Injectable (Vivitrol): 380 mg by deep gluteal injection every 4 weeks. 'Low-dose naltrexone' (LDN, roughly 1.5–4.5 mg nightly) is a separate off-label practice with a different proposed mechanism and a preliminary evidence base.

Effects Erowid

Aggregated from 6 single-substance Erowid experience reports; 9 Erowid reports where another drug was taken too are left out

Each bar shows the share of analyzed reports whose text mentions that effect — a mention is not always a first-hand experience (fear of an effect or something witnessed can count). Mentions saying the effect did not happen are left out; that check reads keywords, so it can miss some. The shaded band on a bar, and the small range after its number, is the 95% interval: where the share could plausibly be with other reports of the same kind. Fewer reports, wider band. Tap or hover any number for details. The second value is the Bluelight extractor's per-effect confidence; a dash means the row is Erowid-derived, which has no confidence measurement.

Too few reports for bars: these effects come from 6 single-substance Erowid reports, and a bar is drawn only from 20 reports or more. With fewer, a percentage cannot tell a common effect from a rare one. Counts are shown instead. Why 20?

Also reported in combinations. In the 9 Naltrexone reports where another drug was taken too, 3 mention hospital, emergency services or an overdose, 0 a seizure and 0 psychosis (too few reports for percentages). In the 6 single-substance reports: 0, 1 and 0. These are not in the figures above: they cannot be put down to Naltrexone alone, and a mention is not always something that happened to the writer.

Combinations

Pill Identifiers

Helpful Links