Medically reviewed on March 25, 2018
(pen TAZ oh seen)
- Pentazocine Lactate
Excipient information presented when available (limited, particularly for generics); consult specific product labeling. [DSC] = Discontinued product
Talwin: 30 mg/mL (1 mL [DSC])
Talwin: 30 mg/mL (10 mL) [contains methylparaben, sodium bisulfite]
Brand Names: U.S.
- Analgesic, Opioid
- Analgesic, Opioid Partial Agonist
Agonist of kappa opiate receptors and partial agonist of mu opiate receptors in the CNS, causing inhibition of ascending pain pathways, altering the perception of and response to pain; produces analgesia, respiratory depression and sedation similar to opioids
Oral [Canadian product]: Well absorbed; bioavailability is low due to extensive first-pass effect
Children 4 to 8 years (mean ± SD): Vdss: 4 ± 1.2 L/kg (Hanunen 1993)
Hepatic via oxidative and glucuronide conjugation pathways; extensive first-pass effect
Urine (small amounts as unchanged drug)
Onset of Action
IM, SubQ: 15 to 20 minutes; IV: 2 to 3 minutes; Oral [Canadian product]: 15 to 30 minutes
Time to Peak
Oral [Canadian product]: 1 to 3 hours
Duration of Action
Injection: 2 to 3 hours; Oral [Canadian product]: ≥3 hours
Prolonged with hepatic impairment
Neonates: 8 to 12 hours (estimated; Osifo 2008)
Children 4 to 8 years (mean ± SD): 3 ± 1.5 hours (Hanunen 1993)
Adults: 2 to 5 hours (Talwin Canadian product labeling 2016)
Special Populations: Elderly
Longer mean elimination half-life, lower mean total plasma Cl, and a larger mean AUC.
Use: Labeled Indications
Anesthesia: Sedative prior to surgery; supplement to surgical anesthesia.
Pain management: Management of pain severe enough to require an opioid analgesic and for which alternative treatments are inadequate.
Oral [Canadian product]: Pain management: Management of chronic or acute pain of moderate to severe degree.
Limitations of use: Reserve pentazocine for use in patients for whom alternative treatment options (eg, nonopioid analgesics, opioid combination products) are ineffective, not tolerated, or would be otherwise inadequate to provide sufficient management of pain.
Hypersensitivity (eg, anaphylaxis) to pentazocine or any component of the formulation; significant respiratory depression; acute or severe bronchial asthma in an unmonitored setting or in the absence of resuscitative equipment; GI obstruction, including paralytic ileus (known or suspected).
Canadian labeling: Additional contraindications (not in US labeling): Hypersensitivity to other opioids; suspected surgical abdomen (eg, acute appendicitis, pancreatitis); mild pain that can be managed with other pain medications; chronic obstructive airway; status asthmaticus; hypercapnia; cor pulmonale; acute alcoholism, delirium tremens, convulsive disorders; severe CNS depression, increased cerebrospinal or intracranial pressure, and head injury; concomitant use or use within 14 days of monoamine oxidase (MAO) inhibitors; pregnancy (oral); breastfeeding (oral)
Documentation of allergenic cross-reactivity for opioids is limited. However, because of similarities in chemical structure and/or pharmacologic actions, the possibility of cross-sensitivity cannot be ruled out with certainty.
Anesthesia, pain management:
IM, SubQ: 30 mg every 3 to 4 hours; do not exceed 60 mg/dose (maximum: 360 mg/day)
IV: 30 mg every 3 to 4 hours; do not exceed 30 mg/dose (maximum: 360 mg/day)
IM: 30 mg once
IV: 20 mg every 2 to 3 hours as needed (maximum total dose: 60 mg)
Discontinuation of therapy: Decrease dose by 25% to 50% every 2 to 4 days; monitor carefully for signs/symptoms of withdrawal. If patient displays withdrawal symptoms, increase dose to previous dose and then reduce dose more slowly by increasing interval between dose reductions, decreasing amount of daily dose reduction, or both.
Oral [Canadian product]: Pain management:
Not receiving opioids at time of initiation: Initial: 50 mg every 4 hours; titrate per response and tolerability to 50 to 100 mg every 3 to 4 hours. Maximum dose: 600 mg/day.
Receiving opioids at time of initiation: Refer to manufacturer’s labeling for detailed dosing conversion.
Discontinuation of therapy: Following prolonged therapy, withdraw gradually and monitor for signs/symptoms of withdrawal.
Use with caution; may be more sensitive to analgesic and sedative effects; decrease initial dose and monitor closely
Analgesia (off-label use): IM:
Children 5 to 8 years: 15 mg (Waterworth 1974)
Children ≥9 years to Adolescents ≤14 years: 30 mg (Waterworth 1974)
Anesthesia, preoperative sedation: Children ≥1 years and Adolescents ≤16 years: Single dose: IM: 0.5 mg/kg
Dosing: Renal Impairment
There are no dosage adjustments provided in the manufacturer’s labeling. Use with caution. The following recommendations have been used by some clinicians (Aronoff, 2007):
GFR ≥50 mL/minute: No dosage adjustment necessary.
GFR 10 to 50 mL/minute: Administer 75% of normal dose.
GFR <10 mL/minute: Administer 50% of normal dose.
Dosing: Hepatic Impairment
There are no dosage adjustments provided in the manufacturer’s labeling. However, dosage adjustment may be necessary due to decreased metabolism and predisposition to adverse effects. Use with caution.
Injection: For IM, IV, or SubQ use. Rotate injection sites for IM administration (eg, the upper outer quadrants of the buttocks, mid-lateral aspects of the thighs, and the deltoid areas); avoid intra-arterial injection; avoid SubQ use unless absolutely necessary (may cause tissue damage).
Oral: Tablet [Canadian product]: For oral use only. Administer after meals. Swallow whole; tablets should not be crushed, chewed, broken or dissolved.
Injection: Store at 20°C to 25°C (68°F to 77°F).
Tablets [Canadian product]: Store at 15°C to 30°C (59°F to 86°F).
Alvimopan: Opioid Analgesics may enhance the adverse/toxic effect of Alvimopan. This is most notable for patients receiving long-term (i.e., more than 7 days) opiates prior to alvimopan initiation. Management: Alvimopan is contraindicated in patients receiving therapeutic doses of opioids for more than 7 consecutive days immediately prior to alvimopan initiation. Consider therapy modification
Amphetamines: May enhance the analgesic effect of Opioid Analgesics. Monitor therapy
Anticholinergic Agents: May enhance the adverse/toxic effect of Opioid Analgesics. Specifically, the risk for constipation and urinary retention may be increased with this combination. Monitor therapy
Azelastine (Nasal): CNS Depressants may enhance the CNS depressant effect of Azelastine (Nasal). Avoid combination
Blonanserin: CNS Depressants may enhance the CNS depressant effect of Blonanserin. Consider therapy modification
Brimonidine (Topical): May enhance the CNS depressant effect of CNS Depressants. Monitor therapy
Bromopride: May enhance the CNS depressant effect of CNS Depressants. Monitor therapy
Bromperidol: May enhance the CNS depressant effect of CNS Depressants. Avoid combination
Buprenorphine: Opioids (Mixed Agonist / Antagonist) may diminish the therapeutic effect of Buprenorphine. This combination may also induce opioid withdrawal. Avoid combination
Cannabis: May enhance the CNS depressant effect of CNS Depressants. Monitor therapy
Chlormethiazole: May enhance the CNS depressant effect of CNS Depressants. Management: Monitor closely for evidence of excessive CNS depression. The chlormethiazole labeling states that an appropriately reduced dose should be used if such a combination must be used. Consider therapy modification
Chlorphenesin Carbamate: May enhance the adverse/toxic effect of CNS Depressants. Monitor therapy
CNS Depressants: May enhance the CNS depressant effect of Opioid Analgesics. Management: Avoid concomitant use of opioid analgesics and benzodiazepines or other CNS depressants when possible. These agents should only be combined if alternative treatment options are inadequate. If combined, limit the dosages and duration of each drug. Consider therapy modification
Desmopressin: Opioid Analgesics may enhance the adverse/toxic effect of Desmopressin. Monitor therapy
Dimethindene (Topical): May enhance the CNS depressant effect of CNS Depressants. Monitor therapy
Diuretics: Opioid Analgesics may enhance the adverse/toxic effect of Diuretics. Opioid Analgesics may diminish the therapeutic effect of Diuretics. Monitor therapy
Dronabinol: May enhance the CNS depressant effect of CNS Depressants. Monitor therapy
Droperidol: May enhance the CNS depressant effect of CNS Depressants. Management: Consider dose reductions of droperidol or of other CNS agents (e.g., opioids, barbiturates) with concomitant use. Consider therapy modification
Eluxadoline: Opioid Analgesics may enhance the constipating effect of Eluxadoline. Avoid combination
Flunitrazepam: CNS Depressants may enhance the CNS depressant effect of Flunitrazepam. Consider therapy modification
Gastrointestinal Agents (Prokinetic): Opioid Analgesics may diminish the therapeutic effect of Gastrointestinal Agents (Prokinetic). Monitor therapy
Kava Kava: May enhance the adverse/toxic effect of CNS Depressants. Monitor therapy
Lofexidine: May enhance the CNS depressant effect of CNS Depressants. Monitor therapy
Magnesium Sulfate: May enhance the CNS depressant effect of CNS Depressants. Monitor therapy
Methotrimeprazine: CNS Depressants may enhance the CNS depressant effect of Methotrimeprazine. Methotrimeprazine may enhance the CNS depressant effect of CNS Depressants. Management: Reduce adult dose of CNS depressant agents by 50% with initiation of concomitant methotrimeprazine therapy. Further CNS depressant dosage adjustments should be initiated only after clinically effective methotrimeprazine dose is established. Consider therapy modification
MetyroSINE: CNS Depressants may enhance the sedative effect of MetyroSINE. Monitor therapy
Minocycline: May enhance the CNS depressant effect of CNS Depressants. Monitor therapy
Nabilone: May enhance the CNS depressant effect of CNS Depressants. Monitor therapy
Nalmefene: May diminish the therapeutic effect of Opioid Analgesics. Management: Avoid the concomitant use of nalmefene and opioid analgesics. Discontinue nalmefene 1 week prior to any anticipated use of opioid analgesics. If combined, larger doses of opioid analgesics will likely be required. Consider therapy modification
Naltrexone: May diminish the therapeutic effect of Opioid Analgesics. Management: Seek therapeutic alternatives to opioids. See full drug interaction monograph for detailed recommendations. Consider therapy modification
Opioid Analgesics: Opioids (Mixed Agonist / Antagonist) may diminish the analgesic effect of Opioid Analgesics. Management: Seek alternatives to mixed agonist/antagonist opioids in patients receiving pure opioid agonists, and monitor for symptoms of therapeutic failure/high dose requirements (or withdrawal in opioid-dependent patients) if patients receive these combinations. Exceptions: Buprenorphine; Butorphanol; Meptazinol; Nalbuphine; Pentazocine. Avoid combination
Orphenadrine: CNS Depressants may enhance the CNS depressant effect of Orphenadrine. Avoid combination
Oxomemazine: May enhance the CNS depressant effect of CNS Depressants. Avoid combination
Paraldehyde: CNS Depressants may enhance the CNS depressant effect of Paraldehyde. Avoid combination
Pegvisomant: Opioid Analgesics may diminish the therapeutic effect of Pegvisomant. Monitor therapy
Perampanel: May enhance the CNS depressant effect of CNS Depressants. Management: Patients taking perampanel with any other drug that has CNS depressant activities should avoid complex and high-risk activities, particularly those such as driving that require alertness and coordination, until they have experience using the combination. Consider therapy modification
Piribedil: CNS Depressants may enhance the CNS depressant effect of Piribedil. Monitor therapy
Pramipexole: CNS Depressants may enhance the sedative effect of Pramipexole. Monitor therapy
Ramosetron: Opioid Analgesics may enhance the constipating effect of Ramosetron. Monitor therapy
ROPINIRole: CNS Depressants may enhance the sedative effect of ROPINIRole. Monitor therapy
Rotigotine: CNS Depressants may enhance the sedative effect of Rotigotine. Monitor therapy
Rufinamide: May enhance the adverse/toxic effect of CNS Depressants. Specifically, sleepiness and dizziness may be enhanced. Monitor therapy
Selective Serotonin Reuptake Inhibitors: CNS Depressants may enhance the adverse/toxic effect of Selective Serotonin Reuptake Inhibitors. Specifically, the risk of psychomotor impairment may be enhanced. Monitor therapy
Serotonin Modulators: Opioid Analgesics may enhance the serotonergic effect of Serotonin Modulators. This could result in serotonin syndrome. Exceptions: Nicergoline. Monitor therapy
Sodium Oxybate: May enhance the CNS depressant effect of CNS Depressants. Management: Consider alternatives to combined use. When combined use is needed, consider minimizing doses of one or more drugs. Use of sodium oxybate with alcohol or sedative hypnotics is contraindicated. Consider therapy modification
Succinylcholine: May enhance the bradycardic effect of Opioid Analgesics. Monitor therapy
Suvorexant: CNS Depressants may enhance the CNS depressant effect of Suvorexant. Management: Dose reduction of suvorexant and/or any other CNS depressant may be necessary. Use of suvorexant with alcohol is not recommended, and the use of suvorexant with any other drug to treat insomnia is not recommended. Consider therapy modification
Tetrahydrocannabinol: May enhance the CNS depressant effect of CNS Depressants. Monitor therapy
Thalidomide: CNS Depressants may enhance the CNS depressant effect of Thalidomide. Avoid combination
Zolpidem: CNS Depressants may enhance the CNS depressant effect of Zolpidem. Management: Reduce the Intermezzo brand sublingual zolpidem adult dose to 1.75 mg for men who are also receiving other CNS depressants. No such dose change is recommended for women. Avoid use with other CNS depressants at bedtime; avoid use with alcohol. Consider therapy modification
Frequency not defined.
Cardiovascular: Circulatory depression, facial edema, flushing, hypertension, hypotension, increased peripheral vascular resistance, shock, syncope, tachycardia
Central nervous system: Central nervous system depression, chills, confusion, disorientation, dizziness, drowsiness, drug dependence (physical and psychological), euphoria, excitement, hallucination, headache, insomnia, irritability, malaise, nightmares, paresthesia, sedation
Dermatologic: Dermatitis, diaphoresis, erythema multiforme, pruritus, skin rash, Stevens-Johnson syndrome, toxic epidermal necrolysis, urticaria
Gastrointestinal: Abdominal distress, anorexia, constipation, diarrhea, dysgeusia, nausea, vomiting, xerostomia
Genitourinary: Urinary retention
Hematologic & oncologic: Agranulocytosis (rare), decreased white blood cell count, eosinophilia
Local: Injection site reaction (tissue damage and irritation)
Neuromuscular & skeletal: Tremor, weakness
Ophthalmic: Blurred vision, diplopia, miosis, nystagmus
Respiratory: Dyspnea, respiratory depression (rare)
Postmarketing and/or case reports: Hypogonadism (Brennan, 2013; Debono, 2011)
Concerns related to adverse effects:
• Cardiovascular effects: May increase systemic and pulmonary arterial pressure and systemic vascular resistance; use with caution in patients who may not tolerate these alterations in hemodynamics (eg, acute MI).
• CNS depression: May cause CNS depression, which may impair physical or mental abilities; patients must be cautioned about performing tasks which require mental alertness (eg, operating machinery or driving).
• Hypotension: May cause severe hypotension (including orthostatic hypotension and syncope); use with caution in patients with hypovolemia, cardiovascular disease (including acute MI), or drugs which may exaggerate hypotensive effects (including phenothiazines or general anesthetics). Monitor for symptoms of hypotension following initiation or dose titration. Avoid use in patients with circulatory shock.
• Injection-site reactions: Severe sclerosis of the skin, subcutaneous tissues, and underlying muscle has occurred at the injection-site following multiple injections; avoid SubQ use unless absolutely necessary; rotate sites of injection.
• Respiratory depression: [US Boxed Warning]: Serious, life-threatening, or fatal respiratory depression may occur. Monitor closely for respiratory depression, especially during initiation or dose escalation. Carbon dioxide retention from opioid-induced respiratory depression can exacerbate the sedating effects of opioids.
• Abdominal conditions: May obscure diagnosis or clinical course of patients with acute abdominal conditions.
• Adrenocortical insufficiency: Use with caution in patients with adrenal insufficiency, including Addison disease. Long-term opioid use may cause secondary hypogonadism, which may lead to sexual dysfunction, infertility, mood disorders, and osteoporosis (Brennan 2013).
• Biliary tract impairment: Use with caution in patients with biliary tract dysfunction or acute pancreatitis; opioids may cause constriction of sphincter of Oddi.
• CNS depression/coma: Avoid use in patients with impaired consciousness or coma as these patients are susceptible to intracranial effects of CO2 retention.
• Delirium tremens: Use with caution in patients with delirium tremens.
• Head trauma: Use with extreme caution in patients with head injury, intracranial lesions, or elevated intracranial pressure; exaggerated elevation of ICP may occur.
• Hepatic impairment: Use with caution in patients with hepatic impairment.
• Obesity: Use with caution in patients who are morbidly obese.
• Prostatic hyperplasia/urinary stricture: Use with caution in patients with prostatic hyperplasia and/or urinary stricture.
• Psychosis: Use with caution in patients with toxic psychosis.
• Renal impairment: Use with caution in patients with renal impairment.
• Respiratory disease: Use with caution and monitor for respiratory depression in patients with significant chronic obstructive pulmonary disease or cor pulmonale, and those with a substantially decreased respiratory reserve, hypoxia, hypercapnia, or preexisting respiratory depression, particularly when initiating and titrating therapy; critical respiratory depression may occur, even at therapeutic dosages. Consider the use of alternative nonopioid analgesics in these patients.
• Seizures: Use with caution in patients with a history of seizure disorders; may cause or exacerbate preexisting seizures.
• Thyroid dysfunction: Use with caution in patients with thyroid dysfunction.
Concurrent drug therapy issues:
• Benzodiazepines or other CNS depressants: [US Boxed Warning]: Concomitant use of opioids with benzodiazepines or other CNS depressants, including alcohol, may result in profound sedation, respiratory depression, coma, and death. Reserve concomitant prescribing of pentazocine and benzodiazepines or other CNS depressants for use in patients for whom alternative treatment options are inadequate. Limit dosage and durations to the minimum required and follow patients for signs and symptoms of respiratory depression and sedation.
• Drug-drug interactions: Potentially significant interactions may exist, requiring dose or frequency adjustment, additional monitoring, and/or selection of alternative therapy. Consult drug interactions database for more detailed information.
• Cachectic or debilitated patients: Use with caution in cachectic or debilitated patients; there is a greater potential for critical respiratory depression, even at therapeutic dosages. Consider the use of alternative nonopioid analgesics in these patients.
• Elderly: Use with caution in the elderly; may be more sensitive to adverse effects. Consider the use of alternative nonopioid analgesics in these patients.
• Neonates: Neonatal withdrawal syndrome: [US Boxed Warning]: Prolonged use of opioids during pregnancy can cause neonatal withdrawal syndrome, which may be life-threatening if not recognized and treated according to protocols developed by neonatology experts. If opioid use is required for a prolonged period in a pregnant woman, advise the patient of the risk of neonatal opioid withdrawal syndrome and ensure that appropriate treatment will be available. Signs and symptoms include irritability, hyperactivity and abnormal sleep pattern, high pitched cry, tremor, vomiting, diarrhea and failure to gain weight. Onset, duration and severity depend on the drug used, duration of use, maternal dose, and rate of drug elimination by the newborn.
Dosage form specific issues:
• Sulfites: Some preparations may contain sulfites which may cause allergic reactions.
• Abuse/misuse/diversion: [US Boxed Warning]: Pentazocine exposes patients and other users to the risks of addiction, abuse, and misuse, potentially leading to overdose and death. Assess each patient’s risk prior to prescribing; monitor all patients regularly for development of these behaviors or conditions. Use with caution in patients with a history of drug abuse or acute alcoholism; potential for drug dependency exists.
• Appropriate use: Oral tablet [Canadian product]: Tablets are intended for oral administration only; do not administer rectally.
• Optimal regimen: An opioid-containing analgesic regimen should be tailored to each patient's needs and based upon the type of pain being treated (acute versus chronic), the route of administration, degree of tolerance for opioids (naive versus chronic user), age, weight, and medical condition. The optimal analgesic dose varies widely among patients; doses should be titrated to pain relief/prevention.
• Withdrawal: Concurrent use of agonist/antagonist analgesics may precipitate withdrawal symptoms and/or reduced analgesic efficacy in patients following prolonged therapy with mu opioid agonists. Taper dose to decrease risk of withdrawal symptoms.
Relief of pain, respiratory and mental status, blood pressure; signs or symptoms of hypogonadism or hypoadrenalism (Brennan, 2013)
Adverse events have been observed in animal reproduction studies. Pentazocine is approved for pain relief during labor. When used for pain relief during labor, opioids may temporarily affect the heart rate of the fetus (ACOG 2002).
[US Boxed Warning]: Prolonged use of opioids during pregnancy can cause neonatal withdrawal syndrome, which may be life-threatening if not recognized and treated according to protocols developed by neonatology experts. If opioid use is required for a prolonged period in a pregnant woman, advise the patient of the risk of neonatal opioid withdrawal opioid withdrawal syndrome and ensure that appropriate treatment will be available. If chronic opioid exposure occurs in pregnancy, adverse events in the newborn (including withdrawal) may occur; monitoring of the neonate is recommended. The minimum effective dose should be used if opioids are needed (Chou 2009). Neonatal abstinence syndrome following opioid exposure may present with autonomic (eg, fever, temperature instability), gastrointestinal (eg, diarrhea, vomiting, poor feeding/weight gain), or neurologic (eg, high-pitched crying, increased muscle tone, irritability, seizure, tremor) symptoms (Dow 2012; Hudak 2012). Neonatal abstinence syndrome has been reported following prolonged use of pentazocine during pregnancy.
Long-term opioid use may cause secondary hypogonadism, which may lead to sexual dysfunction or infertility (Brennan 2013).
• Discuss specific use of drug and side effects with patient as it relates to treatment. (HCAHPS: During this hospital stay, were you given any medicine that you had not taken before? Before giving you any new medicine, how often did hospital staff tell you what the medicine was for? How often did hospital staff describe possible side effects in a way you could understand?)
• Patient may experiencevomiting or nausea. Have patient report immediately to prescriber difficulty breathing, slow breathing, shallow breathing, noisy breathing, signs of serotonin syndrome (dizziness, severe headache, agitation, hallucinations, tachycardia, abnormal heartbeat, flushing, tremors, sweating a lot, change in balance, severe nausea, or severe diarrhea), signs of adrenal gland problems (severe nausea, vomiting, severe dizziness, passing out, muscle weakness, severe fatigue, mood changes, lack of appetite, or weight loss), severe dizziness, passing out, severe fatigue, mood changes, confusion, seizures, severe constipation, severe abdominal pain, sexual dysfunction (males), amenorrhea, decreased libido, infertility, or severe injection site irritation (HCAHPS).
• Educate patient about signs of a significant reaction (eg, wheezing; chest tightness; fever; itching; bad cough; blue skin color; seizures; or swelling of face, lips, tongue, or throat). Note: This is not a comprehensive list of all side effects. Patient should consult prescriber for additional questions.
Intended Use and Disclaimer: Should not be printed and given to patients. This information is intended to serve as a concise initial reference for health care professionals to use when discussing medications with a patient. You must ultimately rely on your own discretion, experience, and judgment in diagnosing, treating, and advising patients.
Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.
More about pentazocine
- Pentazocine Side Effects
- During Pregnancy or Breastfeeding
- Dosage Information
- Drug Interactions
- Support Group
- En Español
- 9 Reviews – Add your own review/rating
- Drug class: narcotic analgesics