Pentazocine is indicated for the management of moderate to severe pain. It may also be used as a preoperative or pre-anesthetic medication and as an adjunct to surgical anesthesia.

Pentazocine is an opioid (narcotic) analgesic that acts on the brain and central nervous system to reduce the perception of pain. It produces analgesic effects primarily through agonist activity at kappa receptors and exhibits weak antagonist activity at mu (μ) opioid receptors.

Onset of action: Intramuscular (IM) or subcutaneous administration: 15–20 minutes Intravenous (IV) administration: 2–3 minutes

Distribution: Moderately bound to plasma proteins

Metabolism: Primarily metabolized in the liver

Elimination: Mainly excreted through the kidneys, with a half-life of approximately 2 to 3 hours

Usual Adult Dose for Anesthesia & Moderate to severe pain: 30 mg by IV, IM or SC. This may be repeated every 3 to 4 hours. Doses in excess of 30 mg intravenously or 60 mg intramuscularly or subcutaneously are not recommended. Maximum daily dose: 360 mg

Usual Adult Dose for Labor Pain: 30 mg intramuscularly once has been the most common dose administered. An intravenous 20 mg dose has given adequate pain relief to some patients in labor when contractions become regular. This dose may be given two or three times at two or three hour intervals as needed.

Dose for Children >1year old: 0.5 mg/kg by intramuscular injection.

Alcohol consumption should be strictly avoided while using Pentazocine, as combining the two may lead to serious side effects or even death. Concurrent use with other medications that cause sedation or slow breathing may intensify these effects, increasing the risk of severe drowsiness, dizziness, falls, or accidents. Pentazocine may also interact with various prescription drugs, over-the-counter medicines, vitamins, and herbal supplements.

Pentazocine is contraindicated in patients with known hypersensitivity to the drug.

The most commonly reported side effects include nausea, dizziness or light-headedness, vomiting, and euphoria. Other possible adverse effects may involve the skin, respiratory system, cardiovascular system, and gastrointestinal tract.

Pregnancy Category C. Pentazocine should be used during pregnancy only if clearly needed. There is insufficient data regarding its excretion into human breast milk.

Pentazocine should be used with caution and at lower doses in patients with respiratory depression. Although no clear evidence suggests worsening of liver or kidney function, caution is advised in patients with hepatic or renal impairment. Pentazocine has mild opioid antagonist properties and may precipitate withdrawal symptoms in patients previously treated with opioids such as methadone. Use with caution in patients with a history of seizures, as seizures have been reported. Concurrent use with CNS depressants may result in additive central nervous system depression.

Manifestations: Limited clinical data are available to clearly define the signs of pentazocine overdose.
Treatment: Management includes administration of oxygen, intravenous fluids, vasopressors, and other supportive care as required. Assisted or controlled ventilation may be necessary. Naloxone is a specific antidote for respiratory depression caused by overdose or increased sensitivity to pentazocine.

Opioid analgesic

Store below 25°C, protect from light, do not freeze, and keep out of reach of children.