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- Pentazocine Lactate
Excipient information presented when available (limited, particularly for generics); consult specific product labeling.
Talwin: 30 mg/mL (1 mL)
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
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: 15-20 minutes; IV: 2-3 minutes
Duration of Action
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 3 hours
Special Populations: Elderly
Longer mean elimination half-life, lower mean total plasma Cl, and a larger mean AUC.
Use: Labeled Indications
Relief of moderate-to-severe pain; has also been used as a sedative prior to surgery and as a supplement to surgical anesthesia
Hypersensitivity to pentazocine or any component of the formulation
IM, SubQ: 30-60 mg every 3-4 hours; do not exceed 60 mg/dose (maximum: 360 mg/day)
IV: 30 mg every 3-4 hours; do not exceed 30 mg/dose (maximum: 360 mg/day)
IM: 30 mg once
IV: 20 mg every 2-3 hours as needed (maximum total dose: 60 mg)
Use with caution; may be more sensitive to analgesic and sedative effects; decrease initial dose and monitor closely
Analgesia (off-label use): IM:
Children 5-8 years: 15 mg
Children: 9-14 years: 30 mg
Preoperative/preanesthetic: Children 1-16 years: IM: 0.5 mg/kg
Dosing: Renal Impairment
No dosage adjustment provided in manufacturer’s labeling. Use with caution. The following guidelines have been used by some clinicians (Aronoff, 2007):
CrCl ≥50 mL/minute: No dosage adjustment necessary.
CrCl 10-50 mL/minute: Administer 75% of normal dose.
CrCl <10 mL/minute: Administer 50% of normal dose.
Dosing: Hepatic Impairment
No dosage adjustment provided in manufacturer’s labeling. However, dosage adjustment may be necessary due to decreased metabolism and predisposition to adverse effects. Use with caution.
Rotate injection site for IM; avoid intra-arterial injection; avoid SubQ use unless absolutely necessary (may cause tissue damage)
Y-site administration: Incompatible with nafcillin.
Compatibility in syringe: Incompatible with glycopyrrolate, heparin, pentobarbital.
Store at 20°C to 25°C (68°F to 77°F).
Alcohol (Ethyl): CNS Depressants may enhance the CNS depressant effect of Alcohol (Ethyl). Monitor therapy
Alvimopan: Analgesics (Opioid) 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 Analgesics (Opioid). Monitor therapy
Analgesics (Opioid): Mixed Agonist / Antagonist Opioids may diminish the analgesic effect of Analgesics (Opioid). 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; Nalbuphine; Pentazocine. Avoid combination
Anticholinergic Agents: May enhance the adverse/toxic effect of Analgesics (Opioid). Specifically, the risk for constipation and urinary retention may be increased with this combination. Monitor therapy
Antipsychotic Agents (Phenothiazines): May enhance the hypotensive effect of Analgesics (Opioid). 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
Buprenorphine: Mixed Agonist / Antagonist Opioids 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
CNS Depressants: May enhance the adverse/toxic effect of other CNS Depressants. Monitor therapy
Desmopressin: Analgesics (Opioid) may enhance the adverse/toxic effect of Desmopressin. Monitor therapy
Dimethindene: May enhance the CNS depressant effect of CNS Depressants. Monitor therapy
Diuretics: Analgesics (Opioid) may enhance the adverse/toxic effect of Diuretics. Monitor therapy
Doxylamine: May enhance the CNS depressant effect of CNS Depressants. Management: The manufacturer of Diclegis (doxylamine/pyridoxine), intended for use in pregnancy, specifically states that use with other CNS depressants is not recommended. 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: Analgesics (Opioid) may enhance the constipating effect of Eluxadoline. Avoid combination
Flunitrazepam: CNS Depressants may enhance the CNS depressant effect of Flunitrazepam. Consider therapy modification
HydrOXYzine: May enhance the CNS depressant effect of CNS Depressants. Monitor therapy
Kava Kava: May enhance the adverse/toxic 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
Mirtazapine: CNS Depressants may enhance the CNS depressant effect of Mirtazapine. Monitor therapy
Nabilone: May enhance the CNS depressant effect of CNS Depressants. Monitor therapy
Nalmefene: May diminish the therapeutic effect of Analgesics (Opioid). 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 Analgesics (Opioid). Management: Seek therapeutic alternatives to opioids. See full drug interaction monograph for detailed recommendations. Consider therapy modification
Orphenadrine: CNS Depressants may enhance the CNS depressant effect of Orphenadrine. Avoid combination
Paraldehyde: CNS Depressants may enhance the CNS depressant effect of Paraldehyde. Avoid combination
Pegvisomant: Analgesics (Opioid) 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
Pramipexole: CNS Depressants may enhance the sedative effect of Pramipexole. Monitor therapy
Ramosetron: Analgesics (Opioid) 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: Analgesics (Opioid) may enhance the serotonergic effect of Serotonin Modulators. This could result in serotonin syndrome. 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 Analgesics (Opioid). 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
Trimeprazine: May enhance the CNS depressant effect of CNS Depressants. Monitor therapy
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)
Limited to important or life-threatening: 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, heart failure).
• 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 hypotension; use with caution in patients with hypovolemia, cardiovascular disease (including acute MI), or drugs which may exaggerate hypotensive effects (including phenothiazines or general anesthetics).
• Injection-site reactions: Severe sclerosis has occurred at the injection-site following multiple injections; avoid SubQ use unless absolutely necessary; rotate sites of injection.
• Abdominal conditions: May obscure diagnosis or clinical course of patients with acute abdominal conditions.
• Adrenal 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, including acute pancreatitis; may cause constriction of sphincter of Oddi.
• CNS depression/coma: Avoid use in patients with CNS depression or coma as these patients are susceptible to intracranial effects of CO2 retention.
• Drug abuse: Use with caution in patients with a history of drug abuse or acute alcoholism; potential for drug dependency exists. Tolerance, psychological and physical dependence may occur with prolonged use.
• 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 dysfunction.
• 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.
• Renal impairment: Use with caution in patients with renal dysfunction.
• Respiratory disease: Use with caution in patients with pre-existing respiratory compromise (hypoxia and/or hypercapnia), COPD or other obstructive pulmonary disease, and kyphoscoliosis or other skeletal disorder which may alter respiratory function; critical respiratory depression may occur, even at therapeutic dosages.
• Seizures: Use with caution in patients with a history of seizure disorders.
• Thyroid dysfunction: Use with caution in patients with thyroid dysfunction.
Concurrent drug therapy issues:
• 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.
• Sedatives: Effects may be potentiated when used with other sedative drugs or ethanol.
• Debilitated patients: Use with caution in debilitated patients; there is a greater potential for critical respiratory depression, even at therapeutic dosages.
• Elderly: If used in older adults, use lower initial doses.
• Neonates: Neonatal withdrawal syndrome: After chronic maternal exposure to opioids, neonatal withdrawal syndrome may occur in the newborn; monitor neonate closely. 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. Opioid withdrawal syndrome in the neonate, unlike in adults, may be life-threatening and should be treated according to protocols developed by neonatology experts.
Dosage form specific issues:
• Sulfites: Injection may contain sulfites which may cause allergic reaction.
• 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. Abrupt discontinuation following prolonged use may also lead to withdrawal symptoms; 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)
Pregnancy Risk Factor
Adverse events were not found 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).
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.
• 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 experience fatigue, constipation, vomiting, or nausea. Have patient report immediately to prescriber signs of serotonin syndrome (dizziness, severe headache, agitation, hallucinations, tachycardia, arrhythmia, 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, confusion, severe loss of strength and energy, vision changes, hallucinations, seizures, insomnia, difficult urination, sexual dysfunction (males), amenorrhea, decreased libido, fertility problems, 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.