Pentazocine (Talwin) is an opioid pain medicine that is used to treat patients with moderate to severe pain.

Indications of Pentazocine:

• Injection:

  • Anesthesia:

    • It is used for sedation prior to surgery; supplement to surgical anesthesia.

  • Pain management:

    • It is effective for controlling severe pain requiring an opioid analgesic and for which alternative treatments are inadequate.

• Oral [Canadian product]:

  • Pain management:

    • It is prescribed for 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.

Pentazocine (Talwin) dose in adults:

Note: Pentazocine injection has been discontinued in the United States for more than 1 year.

Pentazocine (Talwin) Injection:

• Dose in the Anesthesia for 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.

• Dose in the Labor pain:

  • IM:
    • 30 mg once
  • IV:
    • 20 mg every 2 to 3 hours as needed
    • maximum total dose: 60 mg

Pentazocin Oral:

Dose in the management of Pain:

• Not receiving opioids at the time of initiation:

  • Initial: 50 mg every 4 hours;
  • Titrate the dose per response and tolerability to 50 to 100 mg every 3 to 4 hours.
  • Maximum dose: 600 mg/day.

• Receiving opioids at the time of initiation:

  • Refer to the manufacturer's labeling for detailed dosing conversion.

• Discontinuation of therapy:

  • The dose is gradually tapered when discontinuing chronic opioid therapy.
  • An optimal universal tapering schedule for all patients has not been established.
  • Proposed schedules range from slow (eg, 10% reductions per week) to rapid (eg, 25% to 50% reduction every few days).
  • Tapering schedules should be individualized to minimize opioid withdrawal while considering patient-specific goals and concerns as well as the pharmacokinetics of the opioid being tapered.
  • Slow tapering is required in patients receiving opioids for years, whereas more rapid tapers may be appropriate in patients experiencing severe adverse effects.
  • Signs/symptoms of withdrawal should be carefully monitored.
  • Slow tapering should be done in patients displaying withdrawal symptoms, alterations may include increasing the interval between dose reductions, decreasing amount of daily dose reduction, pausing the taper and restarting when the patient is ready, and/or coadministration of an alpha-2 agonist (eg, clonidine) to blunt withdrawal symptoms.
  • Nonopioid analgesics should be given for pain management during the taper; consider nonopioid adjunctive treatments for withdrawal symptoms (eg, GI complaints, muscle spasm) as required.

Pentazocine (Talwin) dose in children:

Talwin dose in the treatment of perioperative Analgesia: 

• Children 5 to 9 years:

  • Initial: 0.5 mg/kg intravenous administered with induction medication;
  • small incremental doses may be repeated every 30 to 45 minutes as needed if the procedure is prolonged.
  • maximum total dose: 1.5 mg/kg/procedure.
  • Dosing based on a study of pediatric patients (n=50) undergoing surgery.

Pentazocine dose in the treatment of postoperative Analgesia:

• Children 5 to 8 years:

  • 15 mg as a single IM dose

• Children ≥9 years and Adolescents <15 years:

  • 30 mg as a single IM dose

Pentazocine dose in the treatment of preoperative Sedation:

• Children and Adolescents ≤16 years:

  • 0.5 mg/kg intramuscular as a single dose; clinical trials suggest higher doses (0.8 to 1.9 mg/kg/dose) may provide a smoother induction.
  • Note: Usual adult dose: 30 mg/dose.

Pentazocine pregnancy Risk Category: C

• Studies on animal reproduction showed that there were adverse events.
• Pentazocine can be used to relieve pain during labor. However, opioids can temporarily alter the heart rate of the foetus.
• [US Boxed Warning]
  • If long-term opioid use is continued during pregnancy, neonatal withdrawal syndrome may occur. This can be potentially life-threatening. It is important to monitor the neonate closely.
  • The prescribing physician should only prescribe the lowest possible dosage of opioids if necessary.
  • Neonatal withdrawal syndrome is characterized by fever, temperature instability and vomiting, diarrhea, vomiting or poor nutrition/weight gain, high pitched crying, increased muscle tone, irritability and seizure.
  • Long-term therapy can help with secondary hypogonadism, which is a condition that causes sexual dysfunction.

Pentazocine use during breastfeeding:

• It is not known if pentazocine is excreted in breast milk.
• Opioids given during labor can disrupt a newborn's natural instinct to breastfeed.
• Pentazocine therapy for breast-feeding mothers should be monitored for psychotomimetic reactions.
• Monitoring is important because large doses of opioids can cause sedation and apnea.
• According to the manufacturer's instructions, breast-feeding is a decision that depends on the risks and benefits to the infant and the benefits to the mother.

Pentazocine Dose adjustment in renal disease:

• There are no dosage adjustments provided in the manufacturer’s labeling.
• Use with caution.
• The following recommendations have been used by some clinicians.

  • GFR ≥50 mL/minute:

    • No dosage adjustment is necessary.

  • GFR 10 to 50 mL/minute:

    • Administer 75% of the normal dose.

  • GFR <10 mL/minute:

    • Administer 50% of normal dose.

Pentazocine Dose adjustment in liver disease:

There are no dosage adjustments provided in the manufacturer’s labeling. However decreased metabolism and predisposition to adverse effect might need dose reduction.

Side effects of Pentazocine (Talwin):

• 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

• Hypersensitivity:

  • Anaphylaxis

• Local:

  • Injection Site Reaction (Tissue Damage And Irritation)

• Neuromuscular & Skeletal:

  • Tremor
  • Weakness

• Ophthalmic:

  • Blurred Vision
  • Diplopia
  • Miosis
  • Nystagmus

• Otic:

  • Tinnitus

• Respiratory:

  • Dyspnea
  • Respiratory Depression (Rare)

Contraindication to Pentazocine (Talwin):

• Hypersensitivity to pentazocine and any component of the formulation (eg, anaphylaxis).
• GI obstruction/ paralytic ileus
• In a setting that does not have resuscitative equipment, severe bronchial asthma
• Grave respiratory depression

Canadian labeling: Additional contraindications not in US labeling

• Hypersensitivity to other opioids
• Alcoholism
• Delirium tremens
• Acute appendicitis/pancreatitis
• Hypercapnia and COPD are symptoms of status asthmaticus.
• Convulsive disorders, severe CNS depression, head injury, and increased ICP
• Breastfeeding/pregnancy
• Combine within 14 days of monoamine-oxidase inhibitors.

Warnings and precautions

• Cardiovascular effects

  • It is important to avoid it in MI because of its potential for increasing systemic and pulmonary arterial pressures and systemic resistance.

• CNS depression:

  • CNS depression can cause impairments in mental or physical abilities. Patients should be cautious about driving or operating machinery.

• Hypotension

  • Patients with hypovolemia, heart disease, or medications that can exaggerate hypotensive effects (e.g. phenothiazines and general anesthetics), should not take pentazocine.
  • It may cause severe hypotension. Avoid it if you have circulatory shock.

• Injection-site reactions:

  • Subcutaneous injections can cause severe sclerosis in the skin, subcutaneous tissues and underlying muscles.

• Respiratory depression [US Boxed Warning]

  • Respiratory depression should be closely monitored as carbon dioxide retention may exacerbate the sedating effects associated with opioids.

• Conditions abdominales:

  • Patients with acute abdominal conditions may not be diagnosed or treated appropriately.

• Adrenocortical Insufficiency

  • Patients with adrenal insufficiency (Addison disease) should be cautious.
  • Long-term therapy can lead to mood disorder, osteoporosis and sexual dysfunction caused by secondary hypogonadism.

• Insufficiency of the biliary tract:

  • Patients with acute pancreatitis or biliary dysfunction should be cautious. Opioids may cause constriction in the sphincter.

• CNS depression/coma:

  • Patients who are unconscious or comatose are more susceptible to the intracranial effects CO retention. It should therefore not be used.

• Delirium tremens:

  • Patients with delirium-tremens should be taken with caution

• Head trauma

  • If intracranial pressure is increased due to head injury or intracranial lesions, intracranial pressure can rise.

• Hepatic impairment

  • Patients with hepatic impairment should be cautious.

• Obesity:

  • Patients who are severely obese should be taken with caution

• Prostatic hyperplasia/Urinary stricture:

  • Patients with prostatic hyperplasia or urinary stricture should be cautious.

• Psychosis:

  • Patients with toxic psychosis should be treated with caution.

• Renal impairment

  • Patients with impaired renal function should be cautious.

• Respiratory disease

  • It should not be used in COPD, cor pulmonale hypercapnia or preexisting respiratory depression. It is recommended to use alternative non-opioid pain relievers.

• Seizures:

  • Preexisting seizures may be exacerbated or caused by it. Use caution.

• Thyroid dysfunction:

  • Patients with thyroid dysfunction should be cautious.

Pentazocine: Drug Interaction

Monitoring parameters:

• BP
• Respiratory and mental status,
• bowel function
• Pain relief
• signs/symptoms of misuse, abuse, and addiction
• signs or symptoms of hypogonadism or hypoadrenalism.

How to administer Pentazocine (Talwin)?

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).
• The intraarterial injection should be avoided Subcutaneous injection should be only used unless absolutely necessary (may cause tissue damage).

Oral: Tablet [Canadian product]:

• For oral use only. Administer after meals as a whole without crushing, chewing, dissolving or breaking.

Mechanism of action of Pentazocine (Talwin):

• Pentazocine acts as an agonist for kappa opiate and partial agonists for mu opiate in the CNS.
• It alters the perception and response of pain and inhibits the ascending pain pathways.
• This produces analgesia and respiratory depression, and sedation similar in effect to opioids.

Absorption:

• Oral: [Canadian Product]: Well absorbed; low bioavailability due to the extensive first-pass effect

The onset of action:

• IM, SubQ: 15 to 20 minutes.
• IV: 2 to 3 minutes
• Oral [Canadian product]: 15 to 30 minutes

Duration:

• Injection: 2 to 3 hours
• Oral [Canadian product]: ≥3 hours

Protein binding:

• 60%

Time to peak (serum):

• Oral [Canadian product]: 1 to 3 hours

Metabolism: Hepatic via oxidative and glucuronide conjugation pathways; extensive first-pass effect

Half-life elimination: Prolonged with hepatic impairment

• Neonates: 8 to 12 hours
• Children 4 to 8 years (mean ± SD): 3 ± 1.5 hours
• Adults: 2 to 5 hours

Excretion:

• Urine (small amounts as unchanged drug)

International Brands of Pentazocin (Talwin):

• Talwin
• Dolapent
• Fortal
• Fortalgesic[inj.]
• Fortalgesic[Suppos.]
• Fortalgesic[Tab.]
• Fortral
• Fortralin
• Fortralin[inj./rect.]
• Fortralin[inj.]
• Fortwin
• Ospronim
• Pellpenta
• Peltazon
• Pentagin
• Pentajin
• Pental
• Pentawin
• Pentazocinum
• Sosegon
• Sosegon[inj./rect.]
• Stopain
• Talwin
• Talwin Lactate

Pentazocine Brands in Pakistan: