Good
Partially Aligned
Patient Risk:
Moderate
Summary
Many claims align with the provided FDA label text regarding naltrexone’s opioid antagonism, blocking effects, opioid-free interval, overdose risk, and general counseling. However, several claims are unsupported or use incorrect product/strength context (confusing VIVITROL vs 50 mg tablets), and some mechanistic/clinical-effect claims for alcohol and relapse are not directly supported by the supplied label excerpts.
Category Scores
Accurate Statements
Naltrexone is an opioid antagonist.
12.1 Mechanism of Action: "Naltrexone is an opioid antagonist..."
Naltrexone blocks the effects of opioids.
12.2 Pharmacodynamics: "Occupation of opioid receptors by naltrexone may block the effects..." and "The administration of VIVITROL... attenuates or completely blocks... the subjective effects of exogenous opioids."
Naltrexone binds to opioid receptors in the brain.
12.1 Mechanism of Action: "highest affinity for the mu opioid receptor" (label does not explicitly say brain, but receptor binding is described).
By binding to opioid receptors in the brain, naltrexone prevents opioids from producing their euphoric or rewarding effects.
12.2 Pharmacodynamics: "attenuates or completely blocks... subjective effects of exogenous opioids" (label does not use the terms "euphoric or rewarding").
Naltrexone has a significant risk of precipitating severe withdrawal symptoms if taken by a person physically dependent on opioids.
12.2 Pharmacodynamics: "In subjects physically dependent on opioids, VIVITROL will precipitate withdrawal symptomatology." and 5.3: "can be severe enough to require hospitalization."
Patients should be completely abstinent from opioids for at least 7-10 days before starting naltrexone.
2.1: "An opioid-free duration of a minimum of 7–10 days is recommended..." and 5.3: "A... minimum of 7–10 days is recommended..."
Naltrexone carries a risk of liver damage, especially with higher doses or prolonged use.
5.4 Hepatotoxicity: "risk of hepatic injury" and "Cases of hepatitis and clinically significant liver dysfunction..." (label does not state “especially with higher doses or prolonged use” in the provided excerpts).
If a person takes naltrexone and then uses opioids, naltrexone blocks the opioid's effects.
12.2 Pharmacodynamics: "attenuates or completely blocks... subjective effects of exogenous opioids" and 7: "Naltrexone antagonizes the effects of opioid-containing medicines..."
Attempting to overcome naltrexone blockade by taking a large amount of opioid can lead to a potentially fatal overdose.
5.1: "Any attempt... is especially dangerous and may lead to life-threatening opioid intoxication or fatal overdose."
The potentially fatal overdose risk is due to sudden removal of the antagonist effect and the body's compromised tolerance.
Unsupported by provided excerpts (see unsupported/contradiction).
Common side effects of naltrexone include nausea.
17 Patient Counseling: "Patients may experience nausea following the initial injection..." and 10 Overdosage lists nausea among most common effects.
Common side effects of naltrexone include headache.
17 Patient Counseling: "tiredness, headache..."
Common side effects of naltrexone include dizziness.
17 Patient Counseling: "dizziness may occur"; and 10 Overdosage lists dizziness among common effects.
Common side effects of naltrexone include anxiety.
10 Overdosage lists somnolence/dizziness; label excerpts provided do not list anxiety as a common side effect.
Common side effects of naltrexone include sleep disturbances.
Label excerpts provided do not list sleep disturbances.
Naltrexone is used as part of a comprehensive treatment program for individuals with alcohol dependence.
17 Patient Counseling: "VIVITROL has been shown to treat alcohol and opioid dependence only when used as part of a treatment program that includes counseling and support." and 1 Indications excerpt (psychosocial support)
Treatment with VIVITROL should be part of a comprehensive management program that includes psychosocial support.
1 INDICATIONS AND USAGE: "Treatment with VIVITROL should be part of a comprehensive management program that includes psychosocial support."
Unsupported Statements
Naltrexone 50 mg tablets are used for the treatment of opioid dependence.
Provided label excerpts are for VIVITROL (extended-release injectable suspension). Supplied excerpts do not describe “50 mg tablets” or tablet dosing/indication.
Naltrexone 50 mg tablets are used for the treatment of alcohol dependence.
Provided label excerpts are for VIVITROL (extended-release injectable suspension). Supplied excerpts do not describe “50 mg tablets” or tablet dosing/indication.
Naltrexone blocks the effects of alcohol.
Label excerpts state mechanisms are not entirely understood and involvement of endogenous opioid system is suggested; they do not state a direct “blocks the effects of alcohol” formulation.
Naltrexone reduces cravings in individuals recovering from addiction.
No craving-specific claim appears in the provided excerpts.
Naltrexone reduces the likelihood of relapse in individuals recovering from addiction.
No relapse-rate reduction claim is directly present in the provided excerpts.
Naltrexone is approved by the U.S. Food and Drug Administration (FDA) for opioid use disorder.
The supplied excerpts do not provide the boxed/label indication text establishing approval for “opioid use disorder.”
Naltrexone is prescribed for individuals who have stopped taking opioids and are at risk of returning to opioid use.
While opioid-free interval is discussed for initiation, the provided excerpts do not define an indication population as “at risk of returning to opioid use.”
Naltrexone is approved by the U.S. Food and Drug Administration (FDA) for alcohol use disorder.
The supplied excerpts do not provide the indication text establishing approval for “alcohol use disorder.”
Naltrexone is available as a generic medication manufactured by multiple pharmaceutical companies.
No information about generic availability/manufacturers is included in the provided excerpts.
Brand names for naltrexone include Vivitrol (injectable form).
The provided excerpts are explicitly for VIVITROL; however, the label excerpts do not state it as a brand name for naltrexone generally (they do name VIVITROL as a product containing naltrexone). This is not clearly established in the supplied excerpts.
Brand names for naltrexone include Revia (oral tablet).
Revia is not mentioned in the provided excerpts.
The duration of naltrexone treatment varies depending on the individual and their specific treatment plan.
The provided excerpts do not address duration variation across individuals.
Naltrexone is typically prescribed as part of a broader recovery program that may include counseling and support services.
The label excerpt supports comprehensive management including psychosocial support and counseling for alcohol/opioid dependence, but this specific generalized phrasing is not directly stated beyond that; treated as partly covered, not clearly fully supported.
Common side effects of naltrexone include anxiety.
Provided excerpts list depression and other symptoms, but do not list anxiety as a common side effect.
Common side effects of naltrexone include sleep disturbances.
Not found in provided excerpts.
Naltrexone can cause gastrointestinal issues such as vomiting.
Vomiting is mentioned (17 Patient Counseling: "vomiting"), so this is supported. If evaluated strictly, this is supported; however it was included in list—see accurate/unsupported consistency. (No contradiction.)
Naltrexone can cause gastrointestinal issues such as vomiting.
Supported by 17 Patient Counseling: "vomiting".
The potentially fatal overdose risk is due to sudden removal of the antagonist effect and the body's compromised tolerance.
5.1 discusses reduced tolerance after detoxification and blockade waning/dissipating; it does not describe “sudden removal of the antagonist effect.”
Clinical trials have demonstrated naltrexone's efficacy in reducing opioid relapse rates when used consistently as part of a comprehensive treatment program.
Provided excerpts do not include relapse-rate efficacy statements for opioid.
Clinical trials have demonstrated naltrexone's efficacy in reducing alcohol relapse rates when used consistently as part of a comprehensive treatment program.
Provided excerpts do not include relapse-rate efficacy statements for alcohol.
Contradictions
Low
AI Statement
If a person takes naltrexone and then uses opioids, naltrexone blocks the opioid's effects.
Label Reference
No contradiction.
Important Omissions
Product-specific formulation and administration details (VIVITROL is deep intramuscular gluteal injection given by a healthcare provider; not tablets).
Importance:
High
Contraindications (e.g., current physiologic opioid dependence, acute opioid withdrawal, receiving opioid analgesics) were not addressed in the claims list.
Importance:
Moderate
Key cautions about depression/suicidality and other clinically significant adverse reactions listed in the provided adverse reactions section were not included in the claims list.
Importance:
Moderate
Safety Assessment
Potential Patient Risk:
Moderate
Several claims are either unsupported or may mislead by conflating VIVITROL injection labeling with “50 mg tablets,” and some safety-relevant details (e.g., administration constraints, contraindications) are not addressed while other partially-supported statements about overdose mechanism and alcohol blocking are asserted.
Regulatory Assessment
| On Label |
No |
| Off-label Discussion |
No |
| Promotes Unapproved Use |
No |
| Hallucination Risk |
Medium |
Recommendation
Partially Aligned
Primary Issue
Confusion between VIVITROL (extended-release injectable) and “50 mg tablets,” plus multiple unsupported or overly specific efficacy/side-effect claims not present in the provided label excerpts.
Suggested Improvement
Rephrase to align strictly with the supplied VIVITROL label language (avoid “50 mg tablets” unless supported), limit mechanistic and clinical-outcome statements to those directly described in the excerpts, and include key safety label elements (opioid-free interval context, administration by healthcare provider, and contraindications) when making risk-related claims.