Pentazocine

What it is and how it works

Pentazocine is a benzomorphan opioid with agonist activity at kappa-opioid receptors and weak antagonist or partial agonist activity at mu-opioid receptors, providing analgesia with a ceiling effect on respiratory depression.

Indications

Moderate to severe pain, including postoperative pain; premedication and supplementation of anaesthesia in some settings.

Dosage and administration (summary)

By intravenous, intramuscular or subcutaneous injection, usually 30 mg (up to 60 mg intramuscularly or subcutaneously) every 3–4 hours as required; maximum dose per label.

Contraindications

Opioid dependence (may precipitate withdrawal), respiratory depression, raised intracranial pressure or head injury, porphyria, and acute myocardial infarction or heart failure (it increases pulmonary arterial and cardiac workload).

Warnings and precautions

Hallucinations, dysphoria and other psychotomimetic effects are more frequent than with morphine. May antagonise the effects of other opioids and precipitate withdrawal. Repeated subcutaneous injection can cause severe tissue damage at injection sites; rotate sites.

Pregnancy

Use only if clearly needed; use during labour may cause neonatal respiratory depression.

Storage and supply

Store below 25 °C, protected from light; controlled drug requirements apply.

Source: reference summary prepared from the EU SmPC/EPAR, BNF and WHO Model Formulary. The approved product information in Iran governs.