PETHIDINE

Opioid analgesic

Dosage Forms

▼

Injection

50 mg/ml

Uses

▼
  • Moderate to severe pain
  • Obstetric analgesia
  • Pre-operative analgesia

Dose and Duration

▼
Moderate to severe pain

Adult: 25‒100 mg SC or IM every 6‒8 hours or 25‒50 mg slow IV as required

Child > 6 months: 0.5‒2 mg/kg/dose as a single dose

Elderly: 25 mg IM or SC

Analgesia in labour

50‒100 mg IM or SC. Repeat every 1‒3 hours as required. Maximum 400 mg in 24 hours

Pre-operative analgesia

Adult: 50‒100 mg IM one hour before the operation

Child > 6 months: 0.5‒2 mg/kg/dose as a single dose

Contraindications

▼
  • Pheochromocytoma
  • Severe renal failure
  • Head trauma or rib fracture injuries
  • Raised intracranial pressure
  • Acute asthma attack
  • Chronic obstructive pulmonary disease
  • Risk of paralytic ileus (e.g. in pancreatitis)
  • Coma
  • Severe liver impairment
  • Acute alcoholism or delirium tremens
  • Allergy to pethidine
  • History of convulsive disorders (e.g. status epilepticus)
  • Prostate hypertrophy
  • Hypotension

Side Effects

▼
  • Nausea, vomiting, constipation, dry mouth
  • Respiratory depression
  • Restlessness
  • Tremor
  • Hypothermia
  • Convulsions (in overdose)
  • Pupil constriction and miosis

Interactions

▼
  • MAOIs e.g. phenelzine, moclobemide (CNS toxicity causing hypotension or hypertension)
  • Ritonavir (increased risk of pethidine toxicity)
  • Selegiline (increased risk of CNS toxicity)
  • Cimetidine (increased effect of pethidine)
  • Phenytoin (reduced pethidine concentration; increased risk of pethidine metabolites toxicity)
  • Phenothiazine e.g. chlorpromazine, promethazine (may induce severe hypotension)

Patient Instructions

▼
  • Do not drive or operate machinery after taking medicine

Pregnancy

▼
  • Can be used

Breast-feeding

▼
  • Can be used

⚠️ Caution

▼
  • Do not use for severe continuing pain as accumulation of metabolites may result in neurotoxicity
  • In case of overdose, use antidote naloxone 40‒80 micrograms slow IV as required
  • Pethidine is a controlled medicine (narcotic) and should be handled according to the regulations
  • Repeated use can cause dependence
  • Avoid or reduce dose in elderly, neonates, liver and renal impairment patients as they are more prone to respiratory depression and other side effects
  • Use during labour may cause respiratory depression in newborn infant