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Pronunciation: pen-TAZ-oh-seen lak-tate
Class: Opioid agonist-antagonist analgesic
- Injection 30 mg/mL
Produces analgesia by an agonistic effect at the kappa opioid receptor. Weakly antagonizes effects of opiates at mu opioid receptor.
Moderate protein binding. Passes into fetal circulation.
Excreted primarily by the kidney. Half-life is 2 to 3 h.
IM/subcutaneous is 15 to 20 min; IV is 2 to 3 min.
Special PopulationsRenal Function Impairment
No data available.Hepatic Function Impairment
No data available.Elderly
Longer mean elimination half-life, lower mean total plasma Cl, and a larger mean AUC.Children
No data available.
Indications and Usage
Management of moderate to severe pain; preoperative or preanesthetic medication; supplement to surgical anesthesia.
Dosage and AdministrationLabor
IM 30 mg as single dose; alternatively, when contractions are regular, IV 20 mg for 2 to 3 doses given every 2 to 3 h.Moderate to Severe Pain/Surgical Anesthesia/Preoperative or Preanesthetic Medication
IM / subcutaneous / IV 30 mg every 3 to 4 h (max, 360 mg/day). Doses greater than 30 mg IV or 60 mg subcutaneous/IM are not recommended.Premedication for sedation
Children 1 yr of age and older
IM 0.5 mg/kg single dose.
- 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.
- Do not mix in the same syringe with barbiturates; precipitation will occur.
- Constantly rotate injection sites.
Store at 59° to 86°F.
Causes additive CNS depression. Use with caution.Barbiturate anesthetics and any other CNS depressants (eg, antidepressants, benzodiazepines)
Causes increased CNS and respiratory depression.
Circulatory depression, hypertension, shock, tachycardia.
Confusion, depression, disorientation, disturbed dreams, dizziness, euphoria, excitement, faintness, hallucinations, headache, insomnia, irritability, light-headedness, muscle tremor, paresthesia, sedation, syncope, tremor, weakness.
Dermatitis, including pruritus; diaphoresis; flushed skin, including plethora.
Diplopia, miosis, nystagmus, tinnitus, visual blurring and focusing difficultly.
Constipation, cramps, diarrhea, dry mouth, nausea, taste alteration, vomiting.
Cutaneous depression, nodules, severe sclerosis, soft tissue induration, sting on injection, and ulceration at injection sites.
Dyspnea, respiratory depression, transient apnea in newborns whose mothers received parenteral pentazocine during labor.
Allergic reactions (eg, edema of the face, toxic epidermal necrolysis), alterations in rate or strength of uterine contractions during labor, chills, urinary retention.
Category C .
Safety and efficacy not established in children younger than 1 yr of age.
May be more sensitive to the analgesic effects. Use low doses and observe these patients closely for confusion and oversedation.
Labor and Delivery
Use drug with caution in women delivering premature infants.
Special Risk Patients
Use with caution in patients with acute MI accompanied by asthma, cyanosis, decreased respiratory reserve, head injury, hypertension or left ventricular failure, increased intracranial pressure, obstructive pulmonary condition, respiratory depression, or seizure.
Drug may cause allergic-type reactions (eg, anaphylaxis, hives, itching, wheezing) in susceptible persons.
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
Confusion, disorientation, hallucinations, and seizures.
May elevate biliary tract pressure.
Renal or hepatic function impairment
Duration of action may be prolonged; dosage reduction may be required.
Severe sclerosis of skin, subcutaneous tissues, and underlying muscle have occurred at injection sites.
Hypertension, respiratory depression, tachycardia.
- 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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