pentazocine (Discontinued)

Brand and Other Names:Talwin
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Dosing & Uses


Dosage Forms & Strengths

injectable solution: Schedule IV

  • Pentazocine discontinued; available only as fixed dose combinations (ie, pentazocine/acetaminophen, pentazocine/naloxone)
  • 30mg/mL

Treatment of Moderate to Severe Pain

Discontinued product

30 mg IV/IM/SC q3-4hr (not to exceed 30 mg/dose IV or 60 mg/dose IM/SC)

Not to exceed 360 mg/day IV/IM/SC

Labor Pain

30mg IM once OR

20mg IV when contractions become regular; may give q2-3hr PRN; not to exceed 60 mg

Preoperative or Preanesthetic/Supplement to Surgical Anesthesia

30 mg IV/IM/SC q3-4hr (not to exceed 30 mg/dose IV or 60 mg/dose IM/SC)

Not to exceed 360 mg/day IV/IM/SC

Renal Impairment

CrCl 10-50 mL/min: 75% of regular dose

CrCl<10 mL/min: 50% of regular dose

Hepatic Impairment

Use lower dose or avoid in liver disease

See Also Combos With

Acetaminophen: Talacen

ASA: Talwin Compound (discontinued)

Naloxone (Talwin Nx)

Pentazocine HCl tablets (Talwin 50) (discontinued)

Dosage Forms & Strengths

injectable solution: Schedule IV

  • Pentazocine discontinued; available only as fixed dose combinations (ie, pentazocine/acetaminophen, pentazocine/naloxone)
  • 30mg/mL

Preoperative or Preanesthetic/Supplement to Surgical Anesthesia

Discontinued product

>1 year: 0.5 mg/kg IM as a single dose  

Analgesia (Off-label)

<5 years: Safety and efficacy not established

5-8 years: 15 mg IM

>8 years: 30 mg IM

Treatment of moderate to severe pain

30 mg IV/IM/SC q3-4hr (not to exceed 30 mg/dose IV or 60 mg/dose IM/SC)

Not to exceed 360 mg/day IV/IM/SC

Preoperative or preanesthetic/supplement to surgical anesthesia

30 mg IV/IM/SC q3-4hr (not to exceed 30 mg/dose IV or 60 mg/dose IM/SC)

Not to exceed 360 mg/day IV/IM/SC



Interaction Checker

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            Adverse Effects

            Frequency Not Defined




            Abdominal distress




            Diaphoresis, flushed skin (including plethora)

            Rash, pruritus, urticaria

            Edema of the face








            Floating feeling


            Weakness or faintness

            Disturbed dreams




            Circulatory depression


            Increased blood pressure


            Soft tissue induration, nodule

            Cutaneous depression


            Severe sclerosis of the skin

            Depression of leukocytes (especially granulocytes)

            Moderate transient eosinophilia

            Blurred vision

            Focusing difficulty






            Black Box Warnings

            Addiction, abuse, and misuse

            • Therapy exposes patients and other users to the risks of opioid addiction, abuse, and misuse, which can lead to overdose and death; assess each patient’s risk prior to prescribing therapy, and monitor all patients regularly for the development of these behaviors and conditions

            Life-threatening respiratory depression

            • Serious, life-threatening, or fatal respiratory depression may occur with use of drug; monitor for respiratory depression, especially during initiation of therapy or following a dose increase.

            Neonatal opioid withdrawal syndrome

            • Prolonged therapy during pregnancy can result in neonatal opioid withdrawal syndrome, which may be life-threatening if not recognized and treated, and requires management 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

            Interaction with central nervous system (CNS) depressants

            • Coadministration with benzodiazepines or other CNS depressants, including alcohol, may result in profound sedation, respiratory depression, coma, and death
            • Reserve concomitant prescribing for use in patients for whom alternative treatment options are inadequate; limit dosages and durations to the minimum required; and follow patients for signs and symptoms of respiratory depression and sedation
            • Instruct patients not to consume alcoholic beverages or use alcohol-containing drug products while taking opioid due to risk of additive sedation and respiratory depression


            Toxin-mediated diarrhea, pseudomembranous enterocolitis, respiratory depression


            Cases of serotonin syndrome, a potentially life-threatening condition, reported with concomitant use of serotonergic drugs; this may occur within the recommended dosage range; the onset of symptoms generally occur within several hours to a few days of concomitant use, but may occur later than that; discontinue therapy immediately if serotonin syndrome is suspected

            Therapy may cause severe hypotension including orthostatic hypotension and syncope in ambulatory patients; there is increased risk in patients whose ability to maintain blood pressure has already been compromised by a reduced blood volume or concurrent administration of certain CNS depressant drugs (e.g., phenothiazines or general anesthetics); monitor patients for signs of hypotension after initiating or titrating dosage; in patients with circulatory shock, therapy may cause vasodilation that can further reduce cardiac output and blood pressure; avoid therapy in patients with circulatory shock

            In patients who may be susceptible to intracranial effects of CO2 retention (e.g., those with evidence of increased intracranial pressure or brain tumors), therapy may reduce respiratory drive, and resultant CO2 retention can further increase intracranial pressure; monitor such patients for signs of sedation and respiratory depression, particularly when initiating therapy; opioids may obscure clinical course in a patient with a head injury; avoid the use in patients with impaired consciousness or coma

            Contraindicated in patients with known or suspected gastrointestinal obstruction, including paralytic ileus; may cause spasm of sphincter of Oddi; opioids may cause increases in serum amylase; monitor patients with biliary tract disease, including acute pancreatitis, for worsening symptoms

            Therapy may increase frequency of seizures in patients with seizure disorders and in other clinical settings associated with seizures; monitor patients for worsened seizure control during therapy

            Avoid use of mixed agonist/antagonist (e.g., pentazocine, nalbuphine, and butorphanol) or partial agonist (e.g., buprenorphine) analgesics in patients who are receiving a full opioid agonist analgesic; mixed agonist/antagonist and partial agonist analgesics may reduce analgesic effect and/or precipitate withdrawal symptoms; when discontinuing therapy in physically-dependent patient, gradually taper dosage; do not abruptly discontinue therapy in these patients

            Warn patients not to drive or operate dangerous machinery unless they are tolerant to effects of drug and know how they will react to medication

            While serious, life-threatening, or fatal respiratory depression can occur at any time during therapy, risk is greatest during initiation of therapy or following dosage increase; monitor patients closely for respiratory depression, especially within first 24 to 72 hr of initiating therapy with and following dosage increases; accidental ingestion of even one dose, especially by children, can result in respiratory depression and death due to overdose of opioid

            Opioids can cause sleep-related breathing disorders including central sleep apnea (CSA) and sleep-related hypoxemia; opioid use increases risk of CSA in a dose-dependent fashion; in patients who present with CSA, consider decreasing opioid dosage using best practices for opioid taper

            Profound sedation, respiratory depression, coma, and death may result from concomitant administration with benzodiazepines or other CNS depressants (e.g., non-benzodiazepine sedatives/hypnotics, anxiolytics, tranquilizers, muscle relaxants, general anesthetics, antipsychotics, other opioids, alcohol); because of these risks, reserve concomitant prescribing of these drugs for use in patients for whom alternative treatment options are inadequate

            Use in patients with acute or severe bronchial asthma in an unmonitored setting or in absence of resuscitative equipment is contraindicated; patients with significant chronic obstructive pulmonary disease or cor pulmonale, and with substantially decreased respiratory reserve, hypoxia, hypercapnia, or pre-existing respiratory depression are at increased risk of decreased respiratory drive including apnea, even at recommended dosages

            Life-threatening respiratory depression is more likely to occur in elderly, cachectic, or debilitated patients because they may have altered pharmacokinetics or altered clearance compared to younger, healthier patients; monitor closely

            Monoamine oxidase inhibitors (MAOIs) may potentiate effects of opioid, opioid’s active metabolite, including respiratory depression, coma, and confusion; therapy should not be administered within 14 days of initiating or stopping MAOIs

            Cases of adrenal insufficiency reported with opioid use, more often following greater than one month of use; symptoms may include nausea, vomiting, anorexia, fatigue, weakness, dizziness, and low blood pressure; if adrenal insufficiency is diagnosed, treat with physiologic replacement doses of corticosteroids; wean patient off of opioid to allow adrenal function to recover and continue corticosteroid treatment until adrenal function recovers; other opioids may be tried as some cases reported use of a different opioid without recurrence of adrenal insufficiency

            Use caution when selecting dosage for an elderly patient, usually starting at low end of dosing range, reflecting greater frequency of decreased hepatic, renal, or cardiac function and of concomitant disease or other drug therapy; because elderly patients are more likely to have decreased renal function, care should be taken in dose selection, and may be useful to monitor renal function

            Opioid pharmacokinetics may be altered in patients with renal failure; clearance may be decreased and metabolites may accumulate much higher plasma levels in patients with renal failure as compared to patients with normal renal function; start with a lower than normal dosage or with longer dosing intervals and titrate slowly while monitoring for signs of respiratory depression, sedation, and hypotension

            Use caution in inflammatory bowel disease, acute abdominal pain, BPH, biliary spasm, cardiac conduction disorder, gallbladder disease, hypothyroidism, mood changes, urinary system procedure, renal disease, substance abuse, urethral stricture

            Less risk of respiratory sedation than with pure opioid agonist (dose dependent); highest incidence of psychotomimetic effects of all opioid agonist/antagonists


            Pregnancy & Lactation


            Prolonged use of opioid analgesics during pregnancy can cause neonatal opioid withdrawal syndrome; there are no available data in pregnant women to inform a drug associated risk for major birth defects and miscarriage; published studies with morphine use during pregnancy have not reported a clear association with morphine and major birth defects

            Prolonged use of opioid analgesics during pregnancy for medical or nonmedical purposes can result in physical dependence in the neonate and neonatal opioid withdrawal syndrome shortly after birth; the onset, duration, and severity of neonatal opioid withdrawal syndrome vary based on specific opioid used, duration of use, timing and amount of last maternal use, and rate of elimination of drug by newborn; observe newborns for symptoms of neonatal opioid withdrawal syndrome and manage accordingly

            Severe fetal bradycardia reported when administered during labor; naloxone may reverse these effects; although there are no reports of fetal bradycardia earlier in pregnancy, it is possible it may occur; drug should be used in pregnancy only if clearly needed, if potential benefit outweighs risk to fetus, and if appropriate measures such as fetal monitoring are taken to detect and manage potential adverse effect on fetus

            Labor or delivery

            • Opioids cross placenta and may produce respiratory depression and psycho-physiologic effects in neonates; an opioid antagonist, such as naloxone, must be available for reversal of opioid induced respiratory depression in neonate; drug is not recommended for use in women during and immediately prior to labor, when use of shorter-acting analgesics or other analgesic techniques are more appropriate; opioid analgesics can prolong labor through actions that temporarily reduce strength, duration, and frequency of uterine contractions; however, this effect is not consistent and may be offset by an increased rate of cervical dilatation, which tends to shorten labor; monitor neonates exposed to opioid analgesics during labor for signs of excess sedation and respiratory depression


            • Due to effects of androgen deficiency, chronic use of opioids may cause reduced fertility in females and males of reproductive potential; it is not known whether effects on fertility are reversible


            Drug is present in breast milk; published lactation studies report variable concentrations of drug in breast milk with administration of immediate-release formulation to nursing mothers in early postpartum period

            The developmental and health benefits of breastfeeding should be considered along with mother’s clinical need for therapy; capsules and any potential adverse effects on breastfed infant from therapy or from underlying maternal condition

            Monitor infants exposed to drug through breast milk for excess sedation and respiratory depression; withdrawal symptoms can occur in breastfed infants when maternal administration of an opioid analgesic is stopped, or when breast- feeding is stopped

            Pregnancy Categories

            A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.

            B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.

            C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.

            D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.

            X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.

            NA: Information not available.



            Mechanism of Action

            Opioid agonist; inhibits ascending pain pathways, which causes alteration in response to pain; produces analgesia, respiratory depression, and sedation


            Half-life: 2-3 hr

            Onset: IM 15-20 min; IV 2-3 min

            Duration: IM 2 hr; IV 1 hr

            Peak Plasma Time: IM 15-60 min; IV 15 min

            Concentration: IM 140 ng/mL

            Bioavailability: 60-70%

            Protein Bound: 60%

            Metabolism: liver, (oxidation of terminal methyl groups-dimethyl alkyl side chain); glucuronide conjugation

            Metabolites: Alcoholic/carboxylic acid metabolites

            Excretion: Urine (mainly); feces



            IV Incompatibilities

            Additive: aminophylline, amobarbital, pentobarbital, phenobarbital, sodium bicarbonate

            Syringe: glycopyrrolate, heparin, pentobarbital

            Y-site: nafcillin

            IV Compatabilities

            Syringe: atropine, butorphanol, chlorpromazine, cimetidine, dimenhydrinate, diphenhydramine, droperidol, fentanyl, glycopyrrolate, hydromorphone, hydroxyzine, meperidine, meperidine w/ perphenazine, metoclopramide, morphine, papaveretum, perphenazine, prochlorperazine, promazine, promethazine, ranitidine, scopolamine

            Y-site: heparin, hydrocortisone Na-succinate, KCl, Vit B/C

            IV/IM Administration

            IM, SC, & IV

            Constant rotation of injection site for IM necessary

            Use SC route only when necessary due to tissue damage

            Avoid intra-arterial injection


            Store at room temp

            Protect from heat & freezing



            Medscape prescription drug monographs are based on FDA-approved labeling information, unless otherwise noted, combined with additional data derived from primary medical literature.