Naltrexone (ReVia / Low-Dose LDN)

Metabolicprescriptionoral · inferred

Competitive mu-opioid receptor antagonist used at two distinct dose scales: Low-Dose Naltrexone (LDN, 1.5-4.5 mg at bedtime) for autoimmune, inflammatory, and chronic pain conditions via transient opioid receptor blockade and TLR4 antagonism; and Standard-Dose (50 mg/day) for opioid use disorder and alcohol use disorder (COMBINE trial). Active metabolite 6-beta-naltrexol has longer half-life and contributes substantial antagonist activity. Extensive first-pass metabolism yields ~40% bioavailability. LDN use is off-label and grey-market in many jurisdictions.

Projected serum levels — 4.5 mg, once daily

Maintenance schedule: 4.5 mg once daily (oral).

Modeled steady state after ~1 days: peak ≈ 0.12 mg, trough ≈ 0.002 mg body load. Population-based estimate over 15 days for a 4.5 mg dose at a 70 kg reference body mass — the interactive app scales curves to your doses, timing, and body mass.

Key facts

Category: Metabolic
Route modeled: Oral
Model confidence: inferred
Half-life: 4 h
Common dose: 4.5 mg
Suggested maximum: 100 mg/day
Reference dose range: 2.3–100 mg (single dose)
Suggested cadence: once daily
Validated against: 50 mg oral — Cmax 0.010 mg/L at 1 h

Documented interactions

danger
Naloxone Nasal (Narcan) + Naltrexone (ReVia / Low-Dose LDN) Stacked effects
Naloxone Nasal (Narcan) and Naltrexone (ReVia / Low-Dose LDN) both push the delta opioid, kappa opioid, and mu opioid in the same direction.
moderate
Buprenorphine (Suboxone, Subutex) + Naltrexone (ReVia / Low-Dose LDN) Stacked effects
Buprenorphine (Suboxone, Subutex) and Naltrexone (ReVia / Low-Dose LDN) both push the delta opioid and kappa opioid in the same direction.
moderate
CBD (Cannabidiol) + Naltrexone (ReVia / Low-Dose LDN) CYP inhibition
CBD (Cannabidiol) reversible_inhibitor of UGT2B7 predicted to change Naltrexone (ReVia / Low-Dose LDN) AUC by ~1.30x
moderate
Contrave (Naltrexone/Bupropion) + Naltrexone (ReVia / Low-Dose LDN) Stacked effects
Contrave (Naltrexone/Bupropion) and Naltrexone (ReVia / Low-Dose LDN) both push the kappa opioid and mu opioid in the same direction.
watch
Kratom (Mitragynine) + Naltrexone (ReVia / Low-Dose LDN) Stacked effects
Kratom (Mitragynine) and Naltrexone (ReVia / Low-Dose LDN) both push the delta opioid in the same direction.

Serum checks 5 modeled interaction pairings for naltrexone (revia / low-dose ldn) across your whole stack — absorption conflicts, enzyme inhibition, and nutrient depletion included.

Research behind this entry

The use of low-dose naltrexone (LDN) as a novel anti-inflammatory treatment for chronic pain Younger J et al. · Clinical Rheumatology, 2014 DOI
Comprehensive review of LDN mechanism (TLR4 antagonism, microglial inhibition) and clinical evidence in fibromyalgia, Crohn's disease, and multiple sclerosis, establishing the scientific rationale for LDN use.
Combined pharmacotherapies and behavioral interventions for alcohol dependence: the COMBINE study: a randomized controlled trial Anton RF et al. · JAMA, 2006 DOI
Landmark COMBINE trial (1,383 patients) found naltrexone 100 mg/day plus medical management significantly improved drinking outcomes in alcohol dependence, establishing naltrexone as first-line AUD pharmacotherapy.
Pharmacokinetics and pharmacodynamics of naltrexone after oral and subcutaneous administration Verebey K et al. · Clinical Pharmacology & Therapeutics, 1976 DOI
Foundational PK study establishing naltrexone's rapid absorption, ~40% bioavailability after extensive first-pass metabolism, 4-hour parent half-life, and 13-hour 6-beta-naltrexol metabolite half-life.

3 published studies referenced in the app, each with a plain-language summary.