Pentazocine

Registered South African indications:

• Pain
• Pre-operative premedication

Contraindications

• Hypersensitivity to the active ingredient or any of its excipients
• Hypersensitivity to other opioids
• Significant respiratory depression
• Acute or severe bronchial asthma
• Gastrointestinal obstruction
• Known or suspected paralytic ileus
• Suspected surgical abdomen
• Chronic obstructive airway
• Status asthmaticus
• Hypercapnia
• Cor pulmonale
• Acute alcoholism
• Delirium tremens
• Seizure disorders
• Severe CNS depression
• Increased cerebrospinal or intracranial pressure, and head injury
• Coadministration with monoamine oxidase inhibitors or within 14 days of their use

Cautions

• Pregnancy
• Breastfeeding
• Men and women of childbearing potential
• Moderate to severe renal impairment
• Hepatic impairment
• Elderly
• Porphyria
• Neonates
• Long-term use
• Acute myocardial infarction
• Cardiovascular disease
• Circulatory shock
• Heart failure secondary to chronic lung disease
• Hypovolemia
• Acute abdominal conditions
• Adrenocortical insufficiency
• Addison's disease
• Biliary tract dysfunction
• Acute pancreatitis
• Impaired consciousness
• Coma
• Morbid obesity
• Prostatic hyperplasia
• Urinary stricture
• Toxic psychosis
• Chronic obstructive pulmonary disease
• History of seizure
• Sleep-related disorders
• Central sleep apnoea
• Hypoxemia
• Hyperthyroidism
• Women delivering premature infants
• History of substance abuse
• Abrupt withdrawal
• Cachectic or debilitated patients
• May impair ability to drive and operate machinery

Forms avail. in SA and covered in this monograph: Inj

Anaesthesia, pain management - moderately severe to severe
- Relief of pain in acute and chronic medical disorders
- Relief of pain following minor or major surgery
- Relief of pain due to trauma and orthopaedic conditions
- Relief of pain associated with urological conditions or procedures
- Pre-operative or pre-anaesthetic as a supplement to surgical anaesthesia

• IM/SC: 30-60mg, 3-4hrly; Max: 360mg/24hrs
• IV: 30mg, 3-4hrly; Max: 360mg/24hrs

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IM: Do not exceed 60mg/dose

IV: Do not exceed 30mg/dose

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Injection sites should be varied when frequent IM injections are required

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Gradual tapering of dose required when discontinuing therapy

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Active labour and postpartum

• IM: 30mg, once-off
• IV: 20mg, 2-3hrly as needed; Max: 60mg

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Use with caution for women delivering premature infants

Paed. forms avail. in SA and covered in this monograph: Inj

Pain management - moderately severe to severe

Below 3 years

• Not established for use

Between 3 and 12 years

• IM/SC: Max: 1mg/kg, up to 30mg
• IV: Max: 0.5mg/kg

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Injection sites should be varied when frequent IM injections are required

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Gradual tapering of dose required when discontinuing therapy

Pregnancy

• Caution; positive evidence of risk
• The safe use of pentazocine in pregnancy, other than labour, has not been established
• Pentazocine is a narcotic analgesic that crosses the placenta, and prolonged use during pregnancy may result in neonatal opioid withdrawal syndrome
• Use of opioids during pregnancy may be associated with birth defects such as poor foetal growth, preterm delivery, congenital heart defects and neural tube defects

Breastfeeding

• Caution; not recommended
• It is currently unknown if pentazocine becomes present in breast milk
• A decision must be made whether to discontinue breastfeeding or to discontinue pentazocine therapy taking into account the benefit of breastfeeding for the child and the benefit of therapy for the mother

Fertility

• Sexual dysfunction or infertility may occur in males and females following prolonged use of opioids due to secondary hypogonadism

Renal impairment

• eGFR >50ml/min/1.73m²: No dose adjustment recommended
• eGFR 10-50ml/min/1.73m²: Caution; dose adjustment recommended
  Decrease dose to 75% of normal dose
• eGFR <10ml/min/1.73m²: Caution; dose adjustment recommended 
  Decrease dose to 50% of normal dose

Hepatic impairment

• Caution; no information available
  Dose adjustment may be necessary due to decreased metabolism and predisposition to adverse effects

Elderly

• Caution; dose adjustment recommended
  Initial dose should be decreased, monitor closely

Porphyria Information

• Not classified (NC)

Drugs in Sport

• Prohibited - In competition

Central Nervous System Disorders

• Dizziness
• Sedation
• Headache
• Increased intracranial pressure
• Mood changes
• Anxiety
• Nightmares
• Paresthaesia
• Insomnia
• Disorientation
• Hallucinations
• Grand mal seizures
• Syncope
• Confusion
• Irritability
• Malaise
• Euphoria
• Excitement
• Drug dependence (physical and psychological)

Cardiovascular Disorders

• Tachycardia
• Hypertension
• Circulatory depression
• Hypotension
• Increased peripheral vascular resistance
• Shock

Respiratory Disorders

• Respiratory depression
• Dyspnea

Gastrointestinal Disorders

• Nausea and vomiting
• Dry mouth
• Constipation
• Abdominal distress
• Anorexia

Hepatobiliary Disorders

• Biliary tract spasm

Genitourinary Disorders

• Urinary retention
• Changed uterine contractions

Endocrine and Metabolic Disorders

• Hypogonadism

Musculoskeletal Disorders

• Muscle tremor
• Weakness

Skin and Subcutaneous Tissue Disorders

• Sweating
• Flushing
• Pruritis
• Toxic epidermal necrolysis
• Injection site reactions
• Dermatitis
• Erythema multiforme
• Rash
• Steven-Johnson syndrome
• Urticaria

Immune, Blood and Lymphatic System Disorders

• Allergic reactions
•  Anaphylaxis
• Transient eosinophilia
• Chills
• Facial oedema
• Agranulocytosis
• Decreased white blood cell count

Sensory Disorders

• Vision disturbances
• Dysgeusia
• Blurred vision
• Diplopia
• Miosis
• Nystagmus
• Tinnitus

• Monoamine oxidase inhibitors
• Central nervous system depressants
• Anaesthetics
• Hypnotics
• Sedatives
• Phenothiazines
• Benzodiazepines
• Chlordiazepoxide
• Aminophylline
• Soluble barbituates
• Alcohol
• Azelastine
• Bromperidol
• Buprenorphine
• Chlormethiazole
• Flunitrazepam
• Naltrexone
• Opioid Agonists
• Orphenadrine

• Blood pressure
• Mental status
• Respiratory function

Incompatibilities

• Pentazocine is incompatible in solution with diazepam or chlordiazepoxide and with alkaline substances such as aminophylline and soluble barbiturates
• Such solutions should not be mixed together

Pentazocine is a potent analgesic. Pentazocine is an agonist of kappa opiate receptors and a partial agonist of mu opiate receptors in the central nervous system, resulting in inhibition of ascending pain pathways, modifying the perception and response to pain. It produces analgesia, respiratory depression and sedation similar to morphine-like opioids.

Injection (per ml) 30mg

• Sosenol 30mg Injection (Adcock Ingram)
• Pentazocine Fresenius (Fresenius Kabi)
• Micro-Pentazocine (Micro Healthcare)

Injection (per 1.5ml) 45mg

• Sosenol 45mg Injection (Adcock Ingram)