Therapeutic Classification: antidotes (for opioids)
Pharmacologic Classification: opioid antagonists
Absorption: Well absorbed after IM or SUBQ administration. IV administration results in complete bioavailability. Rapidly absorbed from nasal mucosa.
Distribution: Rapidly distributed to tissues. Crosses the placenta.
Metabolism/Excretion: Metabolized by the liver.
Half-Life: IM, IV, or SUBQ: 30–90 min (up to 3 hr in neonates); Intranasal: 2 hr.
(reversal of opioid effects)
| ROUTE | ONSET | PEAK | DURATION |
|---|
| IV | 1–2 min | unknown | 45 min |
| IM, SUBQ | 2–5 min | unknown | >45 min |
| Intranasal | 8–13 min | unknown | unknown |
Postoperative Opioid-Induced Respiratory Depression
- IV (Adults ): 0.02–0.2 mg every 2–3 min until response obtained; repeat every 1–2 hr if needed.
- IV (Children ): 0.01 mg/kg; may repeat every 2–3 min until response obtained. Additional doses may be given every 1–2 hr if needed.
- IM IV SC (Neonates ): 0.01 mg/kg; may repeat every 2–3 min until response obtained. Additional doses may be given every 1–2 hr if needed.
Opioid-Induced Respiratory Depression During Chronic (>1 wk) Opioid Use
- IV IM SC (Adults >40 kg): 20–40 mcg (0.02–0.04 mg) given as small, frequent (every min) boluses or as an infusion titrated to improve respiratory function without reversing analgesia.
- IV IM SC (Adults and Children <40 kg): 0.005–0.02 mg/dose given as small, frequent (every min) boluses or as an infusion titrated to improve respiratory function without reversing analgesia.
Overdose of Opioids
- IV IM SC (Adults ): Patients not suspected of being opioid dependent: 0.4 mg (10 mcg/kg); may repeat every 2–3 min (IV route is preferred). Some patients may require up to 2 mg. Patients suspected to be opioid dependent: Initial dose should be ↓ to 0.1–0.2 mg every 2–3 min. May also be given by IV infusion at rate adjusted to patient’s response.
- IV IM SC (Children >5 yr or >20 kg): 2 mg/dose; may repeat every 2–3 min.
- IV IM SC (Infants up to 5 yr or 20 kg): 0.1 mg/kg; may repeat every 2–3 min.
- IM SC (Adults and Children ): Zimhi: 5 mg, may repeat every 2–3 min.
- (Adults and Children ): 1 spray (3 mg, 4 mg, 8 mg, or 10 mg) in one nostril; may repeat dose every 2–3 min (with each subsequent dose being administered in alternate nostril).
Opioid-Induced Pruritus
- IV (Children ): 2 mcg/kg/hr continuous infusion, may ↑ by 0.5 mcg/kg/hr every few hrs if pruritus continues.
