Pentazo30 mg/ml

Pentazo is indicated for the relief of moderate to severe pain when the use of an opioid analgesic is appropriate.

• Established/approved use: Management of moderate to severe acute pain, including postoperative pain and pain associated with trauma, when non-opioid options have been inadequate.
• Guideline-supported use: As an alternative analgesic in patients for whom pure mu-opioid agonists are unsuitable, given its mixed agonist-antagonist profile at the opioid receptor.
• Adjunct use: May be used as an adjunct to balanced general anesthesia and for pre-operative or pre-anesthetic sedation/analgesia in monitored settings.

Pentazo should be reserved for situations where the expected benefits outweigh the risks of opioid therapy, and should not be used for mild pain or for pain that can be managed with non-opioid analgesics.

Each dosage unit contains Pentazocine Hydrochloride as the active pharmaceutical ingredient, equivalent to the labeled strength of pentazocine base. Formulations may be available as an injectable solution (for intramuscular, subcutaneous, or slow intravenous use) or as oral tablets, depending on local registration. Please refer to the specific product label for the exact strength and excipients.

Pentazo is a synthetic opioid analgesic belonging to the benzomorphan class, chemically related to the opioid family but pharmacologically distinct in that it acts as a mixed opioid agonist-antagonist. It has been used clinically for several decades for the relief of moderate to severe pain.

Pentazo is prepared for use as an injectable solution or oral tablet. It is a controlled substance in most jurisdictions due to its potential for abuse and dependence.

Pentazo belongs to the therapeutic class of opioid analgesics, specifically the subclass of mixed opioid agonist-antagonists (benzomorphan derivatives).

Pentazocine Hydrochloride exerts its analgesic effect primarily as an agonist at kappa-opioid receptors and as a weak antagonist or partial agonist at mu-opioid receptors. This mixed receptor activity provides analgesia comparable to moderate doses of morphine while carrying a lower (though not absent) risk of classical mu-opioid dependence at usual doses; however, its antagonist activity can precipitate withdrawal in patients who are physically dependent on full mu-opioid agonists.

Following administration, Pentazocine Hydrochloride produces analgesia, sedation, and respiratory depression in a dose-related manner. Doses above the usual analgesic range are associated with psychotomimetic effects (dysphoria, hallucinations, vivid dreams) more frequently than with pure mu-agonist opioids. Pentazocine Hydrochloride is metabolized in the liver, mainly via oxidation and glucuronide conjugation, and metabolites are excreted primarily in the urine.

Pentazo injection should be administered by a healthcare professional via intramuscular, subcutaneous, or slow intravenous injection. Intravenous administration should be given slowly to reduce the risk of adverse effects. Where an oral formulation is used, tablets should be taken exactly as directed by the physician, with or without food. Do not increase the dose or frequency of administration without consulting a physician.

Pentazo has several clinically significant drug interactions:

• Monoamine oxidase inhibitors (MAOIs): Concurrent use with, or use within 14 days of, MAOIs may result in CNS excitation or depression, hypertension, or hypotension; concurrent use is contraindicated (see Contraindications).
• Other CNS depressants (benzodiazepines, sedative-hypnotics, alcohol, general anesthetics, other opioids): Concomitant use increases the risk of profound sedation, respiratory depression, coma, and death; if co-administration is necessary, use the lowest effective doses and monitor closely.
• Full opioid agonists (e.g., morphine, oxycodone) or opioid dependence: Due to its antagonist activity, Pentazo may precipitate withdrawal symptoms in patients physically dependent on full opioid agonists, and may reduce analgesic effect.
• Mixed agonist/antagonist or partial agonist analgesics (e.g., butorphanol, nalbuphine, buprenorphine): May reduce analgesic efficacy of Pentazo or precipitate withdrawal in opioid-dependent patients.

Common and serious adverse effects reported with Pentazo include:

• Common: Dizziness, sedation/drowsiness, nausea, vomiting, constipation, sweating, headache, injection-site reactions (including tissue induration with repeated injections).
• Psychotomimetic effects: Hallucinations, disorientation, confusion, dysphoria, and vivid or unusual dreams, particularly at higher doses.
• Serious/less common: Respiratory depression, hypotension, circulatory depression, cardiac arrest (rare), seizures, and physical dependence with prolonged use (see Precautions and Warnings and Overdose).

Patients should seek medical attention promptly if they experience severe drowsiness, slowed or difficult breathing, or signs of an allergic reaction.

Pregnancy: Pentazo should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. Prolonged use of opioid analgesics, including Pentazo, during pregnancy can cause neonatal opioid withdrawal syndrome, which may be life-threatening if not recognized and treated. A well-established formal pregnancy category is not uniformly applicable across current labeling; use only under close medical supervision.

Lactation: Pentazo and its metabolites may pass into breast milk. Because of the potential for sedation and respiratory depression in the nursing infant, Pentazo should be used during breastfeeding only if clearly needed, with the infant monitored closely for sedation and adequate feeding; consult a physician before use.

Respiratory depression: As with other opioid analgesics, Pentazo can cause dose-related respiratory depression, which may be serious or fatal, particularly in elderly, debilitated, or opioid-naive patients, or when combined with other CNS depressants. Monitor closely, especially during initiation and dose titration.

Abuse and dependence potential: Pentazo is a controlled substance with the potential for misuse, abuse, and physical/psychological dependence. Use the lowest effective dose for the shortest duration necessary.

Precipitated withdrawal: Because of its mixed agonist-antagonist activity, Pentazo may precipitate withdrawal symptoms in patients physically dependent on full opioid agonists.

Psychotomimetic effects: Hallucinations, disorientation, and confusion have been reported, more frequently than with pure opioid agonists, particularly at higher doses.

CNS and cardiovascular effects: May cause sedation impairing the ability to drive or operate machinery, and can cause hypotension; use with caution in patients with head injury, increased intracranial pressure, or cardiovascular instability.

Hepatic and renal impairment: Use with caution and consider dose reduction in patients with significant hepatic or renal impairment (see Use in Special Populations).

This is not an antibiotic; no antimicrobial stewardship language applies.

Overdose with Pentazo may present with severe respiratory depression, extreme drowsiness progressing to stupor or coma, pinpoint or dilated pupils, hypotension, and cardiovascular collapse; seizures may occur in some cases.

Suspected overdose is a medical emergency. Seek immediate medical attention or contact emergency services/poison control. Management in a healthcare facility may include airway support, assisted or controlled ventilation, and administration of an opioid antagonist (e.g., naloxone) under medical supervision; higher or repeated antagonist doses may be required due to pentazocine's mixed receptor activity. Do not attempt to manage a suspected overdose at home.

Store at room temperature (below 30°C), protected from light and moisture. Keep out of reach of children. Do not use after the expiry date.

Elderly: Use Pentazo with caution in elderly patients, starting at the lower end of the dosing range, due to increased sensitivity to respiratory depression, sedation, and hypotension.

Renal impairment: Use with caution; dose reduction and extended dosing intervals may be needed as metabolites may accumulate.

Hepatic impairment: Use with caution and consider dose reduction, as Pentazo is extensively metabolized by the liver.

Pregnancy and lactation: See Pregnancy and Lactation.

Pediatric patients: See Pediatric Uses.

Opioid-tolerant or opioid-dependent patients: Use with caution; Pentazo may precipitate withdrawal (see Interactions and Precautions and Warnings).

Pentazo should be used for the shortest duration consistent with the treatment goals for acute pain, typically limited to a few days. Prolonged or repeated use increases the risk of tolerance, physical dependence, and withdrawal on discontinuation. Continued need for opioid analgesia beyond the initial treatment period should be reassessed regularly by the treating physician.

Opioid analgesic; mixed opioid agonist-antagonist (benzomorphan derivative)

Pentazocine Hydrochloride acts predominantly as an agonist at kappa-opioid receptors, producing analgesia and sedation, while exerting weak antagonist or partial agonist activity at mu-opioid receptors. This mixed mechanism distinguishes it from pure mu-agonist opioids and underlies both its analgesic profile and its capacity to precipitate withdrawal in patients dependent on full mu-agonists.

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The safety and efficacy of Pentazo in pediatric patients, particularly those under 12 years of age, have not been established. Use in children should be avoided unless specifically directed by a pediatric specialist, with close monitoring for respiratory depression and sedation. Pentazo should not be used for pediatric pain management as a first-line option given the availability of better-studied alternatives.