Pentazocine
Pronouncation: (pen-TAZ-oh-seen)Class: Opioid agonist-antagonist analgesic
Trade Names:
Talacen
- Tablets 25 mg pentazocine (as hydrochloride)/650 mg acetaminophen
Trade Names:
Talwin
- Injection 30 mg/mL (as lactate)
Trade Names:
Talwin Compound
- Tablets 12.5 mg pentazocine (as hydrochloride)/325 mg aspirin
Trade Names:
Talwin NX
- Tablets 50 mg pentazocine (as hydrochloride)/0.5 naloxone
Pharmacology
Feedback for Pentazocine
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Produces analgesia by an agonistic effect at the kappa opioid receptor. Weakly antagonizes effects of opiates at mu opioid receptor; does not appear to increase biliary tract pressure.
Pharmacokinetics
Absorption
Well absorbed from GI tract and from subcutaneous and IM sites. Bioavailability is less than 20% (oral).
Distribution
Moderate protein binding. Passes into fetal circulation.
Metabolism
Hepatic, extensive first-pass; also in intestinal mucosa.
Elimination
Primarily kidney (less than 5% unchanged), small amount biliary. T ½ is 2 to 3 h.
Onset
IM/subcutaneous is 15 to 20 min; IV is 2 to 3 min; oral is 15 to 30 min.
Peak
For analgesic effect, IM/subcutaneous is 30 to 60ߙmin; IV is 15 to 30 min; oral is 60 to 90 min.
Duration
IM is 2 to 3 h; subcutaneous is 2 to 3 h; IV is 2 to 3 h; oral is 3 h.
Special Populations
Hepatic Function ImpairmentOral bioavailability is increased by 3-fold in cirrhotic patients.
Indications and Usage
Oral and parenteral formsManagement of moderate to severe pain.
Parenteral formPreoperative or preanesthetic medication; supplement to surgical anesthesia.
Contraindications
Hypersensitivity to naloxone (in Talwin NX ) or sulfites.
Dosage and Administration
LaborAdults
IM 30 mg as single dose; alternatively, when contractions are regular, IV 20ߙmg for 2 to 3 doses given every 2 to 3 h.
PentazocineModerate to Severe Pain Adults
IM / subcutaneous / IV 30 mg every 3 to 4 h prn (max, 360 mg/day). Doses greater than 30 mg IV or 60 mg subcutaneous / IM are not recommended.
AdultsPO 50 mg every 3 to 4 h; increase to 100 mg if necessary (max, 600 mg/day).
Pentazocine 12.5 mg With Aspirin 325 mg ( Talwin Compound )Moderate to Severe Pain Adults
PO 2 tablets 3 to 4 times daily.
Pentazocine 25 mg With Acetaminophen 650 mg ( Talacen )Moderate to Severe Pain Adults
PO 1 tablet every 4 h (max, 6 tablets/day).
General Advice
- For IM administration; inject deep into well-developed tissue.
- For IV administration; inject undiluted by slow bolus. Do not exceed a 30 mg dose.
- Administer subcutaneously only when necessary; severe tissue damage is possible at injection sites.
Storage/Stability
Store in tightly closed, light-resistant containers.
Drug Interactions
AlcoholCauses additive CNS depression.
Barbiturate anesthetics and any other CNS depressants (eg, benzodiazepines, antidepressants)Causes increased CNS and respiratory depression.
Incompatibility
BarbituratesDo not mix in the same syringe with pentazocine; precipitation will occur.
Laboratory Test Interactions
None well documented.
Adverse Reactions
Cardiovascular
Hypotension; hypertension; tachycardia; circulatory depression; shock.
CNS
Lightheadedness; dizziness; euphoria; hallucinations; disorientation; confusion; seizures.
Dermatologic
Nodules, soft tissue induration, depressions, sclerosis and ulceration at injection sites.
EENT
Visual disturbances.
GI
Nausea.
Genitourinary
Urinary retention.
Hematologic
Granulocytopenia.
Respiratory
Respiratory depression; transient apnea in newborns whose mothers received parenteral pentazocine during labor.
Miscellaneous
Anaphylaxis; tolerance; psychological and physical dependence in long-term use.
Precautions
Pregnancy
Category C . Neonatal abstinence syndrome may develop.
Children
Not recommended for children younger than 12 yr of age.
Labor and Delivery
Pentazocine rapidly crosses placenta with cord blood levels 40% to 70% of maternal serum levels. Use drug with caution in women delivering premature infants.
Special Risk Patients
Use with caution in patients with MI, decreased respiratory reserve, asthma, respiratory depression, head injury or increased intracranial pressure.
Sulfite Sensitivity
Drug may cause allergic-type reactions (eg, hives, itching, wheezing, anaphylaxis) in susceptible persons.
Abuse/Dependence/Withdrawal
Abuse potential exists. Abrupt discontinuation after long-term use may cause withdrawal symptoms. Do not substitute other opiates in pentazocine withdrawal syndrome. Pentazocine may induce withdrawal symptoms in narcotic-dependent patients.
Acute CNS manifestations
Hallucinations, disorientation, confusion, and seizures.
Renal or hepatic function impairment
Duration of action may be prolonged; dosage reduction may be required.
“Ts and Blues”
Refers to drug abuse by IV injection of oral pentazocine and tripelennamine (antihistamine) as substitute for heroin. Complications of injecting oral pentazocine include pulmonary emboli, vascular occlusion, ulceration, seizures, strokes, and CNS infections. Addition of naloxone to pentazocine tablets ( Talwin NX ) prevents this drug abuse; it may cause withdrawal in narcotic-dependent individuals.
Tissue damage
Severe sclerosis of skin, subcutaneous tissues, and underlying muscle have occurred at injection sites.
Overdosage
Symptoms
Respiratory depression, hypertension, tachycardia.
Patient Information
- For max effectiveness, instruct patient to take medication before intolerable pain develops.
- Tell patient to take medication exactly as prescribed, to minimize dependence.
- Teach patient to consume 2 to 3 L of fluids each day, if tolerated, to prevent constipation.
- Inform patient that aspirin or acetaminophen may be taken concurrently for additive analgesia as well as its antiinflammatory and antipyretic effects.
- Explain therapeutic value of pentazocine prior to administration to enhance the analgesic effect.
- Caution patient not to stop taking drug abruptly without consulting health care provider.
- Advise patient to avoid sudden position changes to prevent orthostatic hypotension.
- Instruct patient to avoid intake of alcoholic beverages or other CNS depressants.
- Advise patient that drug may cause dizziness and to use caution while driving or performing other tasks requiring mental alertness.
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More Pentazocine resources:
Pentazocine - Includes detailed dosage instructions.
Pain, Sedation, Anesthesia, Labor Pain
