Substance use disorder agents

Substance use disorder agents

Drug monograph · NCLEX study reference
Trade names	Vivitrol, ReVia, Suboxone, Antabuse, Chantix
Therapeutic class	Substance use disorder agents
Pharmacologic class	Opioid antagonist (naltrexone); partial opioid agonist combination (buprenorphine/naloxone); full opioid agonist (methadone); aldehyde dehydrogenase inhibitor (disulfiram); nicotinic partial agonist (varenicline)
Onset / peak / duration	Naltrexone IM lasts a month; methadone long acting; disulfiram effect persists up to 2 weeks after stopping.
Half-life / level	Varies; level not routine.
Routes	PO (oral), IM, Sublingual
High-alert (ISMP)	No
Black box warning	Yes (see Safety)
Antidote / reversal	Naloxone for opioid agonist overdose (higher doses may be needed with buprenorphine); supportive care.
Pregnancy / lactation	Buprenorphine and methadone are used in pregnancy under specialist care; others case by case.

Nursing pharmacology study reference (NCLEX-style monograph). Numeric values are standard teaching ranges for study and must be verified against current manufacturer labeling before clinical use. This is educational content, not prescribing guidance.

Substance use disorder agents (brand names Vivitrol, ReVia, Suboxone, Antabuse, Chantix) — Substance use disorder agents; Opioid antagonist (naltrexone); partial opioid agonist combination (buprenorphine/naloxone); full opioid agonist (methadone); aldehyde dehydrogenase inhibitor (disulfiram); nicotinic partial agonist (varenicline).

Identification

• Therapeutic class: Substance use disorder agents.
• Pharmacologic class: Opioid antagonist (naltrexone); partial opioid agonist combination (buprenorphine/naloxone); full opioid agonist (methadone); aldehyde dehydrogenase inhibitor (disulfiram); nicotinic partial agonist (varenicline).

Pharmacology

• Mechanism of action: Naltrexone blocks opioid receptors to reduce craving in opioid and alcohol use; buprenorphine partially activates opioid receptors to reduce withdrawal and craving; methadone provides controlled opioid agonism; disulfiram causes an aversive reaction with alcohol; varenicline reduces nicotine craving and reward.
• Onset / peak / duration: Naltrexone IM lasts a month; methadone long acting; disulfiram effect persists up to 2 weeks after stopping.
• Half-life / therapeutic level: Varies; level not routine.

Clinical use

• Indications: Alcohol and opioid use disorder (naltrexone), opioid use disorder (buprenorphine/naloxone, methadone), alcohol use disorder deterrence (disulfiram), smoking cessation (varenicline).
• Usual dose, route, frequency: Naltrexone PO daily or IM monthly; buprenorphine/naloxone SL daily; methadone PO daily (clinic dispensed); disulfiram PO daily; varenicline PO titrated.
• Maximum dose / adjustments: Confirm opioid-free interval before naltrexone or buprenorphine to avoid precipitated withdrawal; methadone within a regulated program.

Safety

• Contraindications: Naltrexone with current opioid use or acute withdrawal; disulfiram with recent alcohol or metronidazole; methadone with severe respiratory compromise.
• Black box warning: Methadone carries a boxed warning for respiratory depression, QT prolongation, and abuse potential; the others do not carry boxed warnings (varenicline's prior neuropsychiatric boxed warning was removed).
• Interactions: Naltrexone blocks opioid analgesics; disulfiram with any alcohol (including in foods, mouthwash, or some medications) causes flushing, vomiting, and hypotension; methadone with QT-prolonging and CNS depressant drugs; varenicline with alcohol (mood and intoxication effects).
• Pregnancy / lactation: Buprenorphine and methadone are used in pregnancy under specialist care; others case by case.
• High-alert: No.

Adverse effects

• Common side effects: Nausea and headache (naltrexone, varenicline), constipation and sedation (methadone, buprenorphine), metallic taste (disulfiram), vivid dreams (varenicline).
• Serious effects to report: Precipitated withdrawal, respiratory depression (methadone), severe disulfiram-alcohol reaction, mood changes (varenicline), hepatotoxicity (naltrexone, disulfiram).
• Antidote / reversal: Naloxone for opioid agonist overdose (higher doses may be needed with buprenorphine); supportive care.

Nursing process

• Assessment before administration: Substance use history, opioid-free interval, LFTs, cardiac history (methadone), mood (varenicline).
• Interventions during therapy: Confirm abstinence intervals; counsel disulfiram patients to avoid all alcohol sources; methadone within program rules.
• Monitor: LFTs, mood, respiratory status (methadone), ECG (methadone).
• Evaluation / expected outcome: Reduced substance use and craving.

Patient teaching

• Patient teaching: Naltrexone blocks opioid pain relief (carry medical identification); avoid all alcohol on disulfiram; report mood changes on varenicline.
• Notify provider if: Severe withdrawal, trouble breathing, chest palpitations, severe alcohol reaction, mood changes.
• Administration tips: Buprenorphine SL dissolved fully; methadone clinic dosing; disulfiram never given without the patient's knowledge.