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nalorphine

V03AB02

Forms & Strengths

Injectable solution 1 mg/mL (0.1 %); 2 mg ampoules
Oral tablets 5 mg (historical)

Adult Dosing

0.2–1 mg IV or IM for opioid overdose; may repeat 0.5–1 mg q30 min, max 10 mg total
2–5 mg IM q6h for opioid detoxification

Pediatric Dosing

0.01 mg/kg IV or IM (max 0.5 mg per dose) for overdose reversal; repeat as needed

Indications

Reversal of opioid‑induced respiratory depression
Acute opioid toxicity
Adjunct in opioid dependence detoxification

Mechanism of Action

Competitive antagonist at μ‑opioid receptors; partial agonist at κ receptors
Displaces opioid agonists, reversing analgesia and respiratory depression

Contraindications

Hypersensitivity to nalorphine
Severe circulatory shock
Use in opioid‑dependent patients when abrupt withdrawal is undesirable

Adverse Reactions

Nausea, vomiting
Sweating, yawning
Agitation, anxiety
Hypertension, tachycardia
Withdrawal syndrome in dependent patients

Drug Interactions

May precipitate withdrawal when given with full opioid agonists
CNS depressants may blunt reversal effect
Can augment sympathomimetic effects (↑BP, HR)
Reduces efficacy of mixed agonist‑antagonist opioids (e.g., pentazocine)
Alcohol may increase sedation

Curated Content: Needs Vetting Before Put to Clinical Use