Last reviewed 2026-04-20 · How we verify

Naloxone Hydrochloride

Pentazocine is a mixed agonist-antagonist at opioid receptors; naloxone is an opioid antagonist.

Pentazocine and Naloxone Tablets are indicated for management of severe pain requiring opioid analgesia when alternative treatments are inadequate. The combination product contains a mixed opioid agonist-antagonist with an opioid antagonist component. Significant risks include respiratory depression, addiction, abuse, misuse, overdose, and death, which can occur at any dosage or duration. Reserve use for patients with inadequate response to alternative treatments and implement careful monitoring with CNS depressant co-medications.

At a glance

Mechanism of action

Pentazocine acts as a partial agonist at the mu opioid receptor and an agonist at the kappa opioid receptor, producing analgesic effects through mixed agonist-antagonist activity. Naloxone functions as an opioid antagonist, blocking opioid receptor activity. The combination produces analgesia while the naloxone component is intended to deter abuse through antagonism of opioid effects.

Approved indications

• Management of pain severe enough to require an opioid analgesic
• Pain in patients for whom alternative treatment options are ineffective
• Pain in patients for whom alternative treatment options are not tolerated
• Pain in patients for whom alternative treatment options would be otherwise inadequate

Boxed warnings

• WARNING: SERIOUS AND LIFE-THREATENING RISKS FROM USE OF PENTAZOCINE AND NALOXONE TABLETS Addiction, Abuse, and Misuse Because the use of Pentazocine and Naloxone Tablets exposes patients and other users to the risks of opioid addiction, abuse, and misuse, which can lead to overdose and death, assess each patient's risk prior to prescribing and reassess all patients regularly for the development of these behaviors and conditions [ see <WARNINGS ]. Life-Threatening Respiratory Depression Serious,

Common side effects

• Emergency department visit
• Constipation
• Nausea
• Headache
• Injection site pain
• Insomnia
• Nasopharyngitis
• Injection site erythema
• Vomiting
• Upper respiratory tract infection
• Injection site pruritus
• Blood creatine phosphokinase increased

Drug interactions

• Benzodiazepines and other CNS depressants (alcohol, sedative hypnotics, anxiolytics, tranquilizers, muscle relaxants, general anesthetics, antipsychotics, other opioids)
• Serotonergic drugs (SSRIs, SNRIs, TCAs, triptans, 5-HT3 receptor antagonists, mirtazapine, trazodone, tramadol, cyclobenzaprine, metaxalone, MAO inhibitors, linezolid, intravenous methylene blue)
• Monoamine oxidase inhibitors (MAOIs)

Patents

Primary sources

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Competitive intelligence

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• Naloxone Hydrochloride CI brief — competitive landscape report
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• Pfizer Inc. portfolio CI