Nalmefene

Brand names: Revex
Drug class: Antineoplastic Agents

Usage of Nalmefene

Postoperative Opiate Depression

Treatment of opiate-induced depression, including respiratory depression, caused by natural and synthetic opiates.

Opiate OverdoSage

Management of known or suspected opiate overdosage.

Relate drugs

How to use Nalmefene

Administration

Principally administered by IV injection; can be administered by IM or sub-Q injection if venous access cannot be established.

For reversal of postoperative opiate depression, administer blue-labeled commercially available injection containing 100 mcg/mL nalmefene.

For management of known or suspected opiate overdose, administer green-labeled commercially available injection containing 1 mg/mL nalmefene.

Proper steps should be taken to prevent use of incorrect concentration of injection.

IV Administration

Administer as an IV bolus.

Dilution

When used for treatment of postoperative opiate-induced depression in patients with increased cardiovascular risk, it may be desirable to dilute to a final ratio of 1:1 in 0.9% sodium chloride injection or sterile water for injection. (See Cardiovascular Disease under Cautions.)

Dosage

Available as nalmefene hydrochloride; dosage expressed in terms of nalmefene.

Titrate dosage to reverse opiate-induced effects; when adequate opiate reversal has been established, additional doses of nalmefene are not required and may cause unwanted reversal of analgesia or precipitate withdrawal.

Adults

Postoperative Opiate Depression IV

Initially, 0.25 mcg/kg given at 2- to 5-minute intervals until the desired response is obtained.

Weight-based Initial Dosage in Postoperative Patients a

Patient Weight

Initial Dosage (0.25 mcg/kg)

Volume of Nalmefene 100 mcg/mL Solution (Blue-label) to Administer

50 kg

12.5 mcg

0.125 mL

60 kg

15 mcg

0.15 mL

70 kg

17.5 mcg

0.175 mL

80 kg

20 mcg

0.2 mL

90 kg

22.5 mcg

0.225 mL

100 kg

25 mcg

0.25 mL

Cumulative total dosage >1 mcg/kg does not provide additional therapeutic effect.

Patients at increased cardiovascular risk: Initially, 0.1 mcg/kg given at 2- to 5- minute intervals until desired response is obtained.

Opiate Overdosage IV

Opiate naive patients: Initially, 7.14 mcg/kg (0.5 mg/70 kg), followed by a second dose of 14.29 mcg/kg (1 mg/70 kg) 2–5 minutes later, if necessary.

If no response is observed after a total dose of 21.43 mcg/kg (1.5 mg/70 kg), additional doses are unlikely to provide therapeutic effect.

Patients suspected of opiate Dependency: Initially, 1.43 mcg/kg (100 mcg/70 kg). If no withdrawal is observed within 2 minutes, 7.14 mcg/kg (0.5 mg/70 kg), followed by 14.29 mcg/kg (1 mg/70 kg) 2–5 minutes later, if necessary; observe closely for withdrawal symptoms.

If recurrence of respiratory depression occurs, titrate dosage incrementally to response to avoid over-reversal.

Prescribing Limits

Adults

Postoperative Opiate Depression IV

Cumulative dosage >1 mcg/kg does not provide additional therapeutic effect.

Opiate Overdosage IV

Cumulative dosages ≥21.43 mcg/kg (1.5 mg/70 kg) unlikely to increase therapeutic response.

Special Populations

Hepatic Impairment

Decreased clearance; however, dosage adjustment not required.

Renal Impairment

Decreased clearance. Dosage adjustment not required, however, administer incremental doses slowly (e.g., over 60 seconds) to minimize hypertension and dizziness associated with rapid administration in such patients.

Geriatric Patients

Dosage adjustment not required.

Warnings

Contraindications

  • Known hypersensitivity to nalmefene or any ingredient in the formulation.

    • Warnings/Precautions

    Warnings

    Additional Resuscitative Measures

    When used in emergency settings, other resuscitative measures (e.g., maintenance of an adequate airway, artificial respiration, administration of oxygen, vasopressor agents) should be readily available and used first when necessary.

    Respiratory Depression

    Risk of recurrent respiratory depression in postoperative and overdose patients after initial response to nalmefene.

    Carefully monitor patients who have responded to nalmefene since the duration of action of some opiates (e.g., metHADone and levo-alpha-acetylmethadol [LAAM]) may exceed that of nalmefene; monitor patients until there is no reasonable risk of recurrent respiratory depression.

    General Precautions

    Cardiovascular Disease

    Serious adverse cardiovascular effects (e.g., VT and VF, pulmonary edema, hypertension, hypotension, cardiovascular instability) reported in postoperative patients and in emergency department settings following administration of nalmefene; may be associated with excessive doses.

    Use with caution in patients with preexisting cardiovascular disease or in those receiving potentially cardiotoxic drugs. Reduced dosage recommended in postoperative patients at high risk for cardiovascular complications. (See Adults under Dosage and Administration.)

    Precipitation of Withdrawal

    Possible precipitation of acute withdrawal symptoms. Use with extreme caution in patients with known physical dependence on opiates or following surgery involving high doses of opiates.

    Observe patients suspected of opiate dependency for symptoms of withdrawal following initial and subsequent nalmefene injections.

    Incomplete Reversal of Buprenorphine

    Incomplete reversal of buprenorphine-induced analgesia reported in animal models; therefore, nalmefene may not completely reverse buprenorphine-induced respiratory depression.

    Seizures

    Possible risk of seizures.

    Specific Populations

    Pregnancy

    Category B.

    Lactation

    Distributed into milk in rats; not known whether distributed into human milk. Use caution.

    Pediatric Use

    Safety and efficacy not established in children <18 years of age.

    Safety and efficacy not established in neonates, however, nalmefene may be used in the resuscitation of neonates when benefits outweigh the risks.

    Geriatric Use

    Insufficient experience in patients ≥65 years of age to determine whether geriatric patients respond differently than younger adults. (See Special Populations under Pharmacokinetics.)

    Select dosage with caution because of age-related decreases in hepatic, renal, and/or cardiac function and potential for concomitant disease and drug therapy.

    Hepatic Impairment

    Decreased clearance; however, dosage adjustments not recommended because nalmefene is administered as an acute course of therapy.

    Renal Impairment

    Decreased clearance; administer dosages slowly to minimize adverse effects. (See Renal Impairment under Dosage and Administration.)

    Common Adverse Effects

    Nausea, vomiting, tachycardia, hypertension.

    What other drugs will affect Nalmefene

    Specific Drugs

    Drug

    Interaction

    Comments

    Anesthetics, inhalational

    No deleterious interactions observed when nalmefene was administered after inhalation anesthetics

    Benzodiazepines

    No deleterious interactions observed when nalmefene was administered after benzodiazepines

    Flumazenil

    Risk of seizures

    Skeletal muscle relaxants

    No deleterious interactions observed when nalmefene was administered after skeletal muscle relaxants

    Skeletal muscle relaxant antagonists

    No deleterious interactions observed when nalmefene was administered after skeletal muscle relaxant antagonists and general anesthesia

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