Adult: 50-150 mg 4 hourly as needed. Child: 0.5-2 mg/kg 4 hourly as needed. Elderly: Initiate at the lower end of the dosing range.
Parenteral Obstetric analgesia
Adult: 50-100 mg via IM or SC inj, may be repeated at intervals of 1-3 hours as needed. Max: 400 mg in 24 hours.
Parenteral Moderate to severe acute pain
Adult: 25-150 mg via IM or SC inj 4 hourly as needed; may also be given via slow IV inj at a dose of 25-50 mg, repeated 4 hourly as needed. Adjust dosing based on patient’s tolerability, pain severity and clinical response; use lowest effective dose at the shortest duration. Child: 0.5-2 mg/kg via IM or SC inj, may be repeated after 4 hours as needed. Elderly: Initiate at the lower end of the dosing range.
Parenteral Preoperative medication
Adult: 50-100 mg via IM or SC inj 30-90 minutes before surgery. Child: 1-2 mg/kg via IM or SC inj 30-90 minutes before surgery. Elderly: Use the lower end of the dosing range.
Mild to moderate: Dosage reduction may be needed. Severe: Contraindicated.
Mild to moderate: Dosage reduction may be needed. Severe: Contraindicated.
Oral solution: Dilute each dose in 1/2 glass of water. IV: Dilution with an appropriate diluent to a final concentration of 10 mg/mL is recommended.
Incompatible with aciclovir Na, aminophylline, amobarbital, cefoperazone, doxorubicin hydrochloride, liposomal, furosemide, floxacillin Na, heparin Na, idarubicin hydrochloride, imipenem-cilastatin Na, methicillin Na, mezlocillin Na, minocycline hydrochloride, morphine sulfate, nafcillin Na, nitrofurantoin Na, pentobarbital Na, phenobarbital Na, phenytoin Na, Na bicarbonate, Na iodide, sulfafurazole diethanolamine, tetracycline hydrochloride, and thiopental Na. Also incompatible with, alkalis, iodine and iodides.
Significant respiratory depression (e.g. acute or severe bronchial asthma in unmonitored setting, chronic airway disease, severe emphysema), head injury, increased intracranial pressure, convulsive states (e.g. status epilepticus, tetanus/strychnine poisoning), impaired consciousness, comatose state, diabetic acidosis, acute alcoholism or delirium tremens, pre-eclampsia or eclampsia, phaeochromocytoma, cardiac arrhythmias (e.g. supraventricular tachycardia, cor pulmonale), known or suspected gastrointestinal obstruction (e.g. paralytic ileus), low platelet count, coagulation disorders. Severe renal and hepatic impairment. Concomitant use or within 14 days of using MAOIs; ritonavir.
Patients with CNS disease, CV disease (e.g. unstable angina, acute and post MI), hypovolaemia, abdominal disorder, seizure disorders, adrenal insufficiency (e.g. Addison disease), biliary tract disorder (e.g. acute pancreatitis), severe obesity, prostatic hyperplasia or urinary stricture, toxic psychosis, sickle cell anaemia, sleep disorders, thyroid dysfunction (e.g. hypothyroidism), personal or family history of substance abuse, dependence or mental illness. Debilitated patients. Mild to moderate renal and hepatic impairment. Children and elderly. Pregnancy and lactation. Not recommended for the management of chronic pain.
Significant: Adrenal insufficiency, CNS depression, constipation, severe hypotension (e.g. orthostatic hypotension, syncope), spasm of sphincter of Oddi. Cardiac disorders: Bradycardia, palpitation, tachycardia. Endocrine disorders: Hypogonadism. Eye disorders: Visual disturbances. Gastrointestinal disorders: Dry mouth, nausea, vomiting. General disorders and administration site conditions: Inj site pain, withdrawal symptoms (in abrupt drug discontinuation), weakness. Immune system disorders: Hypersensitivity reaction, histamine release, urticaria. Investigations: Increased serum amylase. Nervous system disorders: Agitation, convulsions, dizziness, headache, involuntary muscle movements (e.g. muscle twitching, myoclonus), sedation, seizure, tremor. Psychiatric disorders: Confusion, drug dependence, delirium, disorientation, hallucination, mood changes (e.g. euphoria, dysphoria). Renal and urinary disorders: Urinary retention. Skin and subcutaneous tissue disorders: Pruritus, rash, sweating. Vascular disorders: Flushing. Potentially Fatal: Respiratory depression, serotonin syndrome, circulatory depression, cardiac arrest, respiratory arrest, shock.
This drug may cause drowsiness or reduce alertness, if affected, do not drive or operate machinery.
Monitor for signs and symptoms of addiction, abuse and misuse; changes in mood, suicidal thoughts or behaviours, withdrawal symptoms; respiratory and CNS depression; hypogonadism or hypoadrenalism; serotonin syndrome. Monitor pain control, blood pressure and renal function regularly.
Symptoms: Respiratory depression that may progress to Cheyne-Stokes respiration or cyanosis, CNS depression (e.g. extreme somnolence, stupor or coma), CNS excitability (e.g. hallucination, tachycardia), seizures, bradycardia, cold and clammy skin, flaccid skeletal muscle, hypothermia, hypotension. For severe cases, mydriasis, pulmonary oedema, cardiac or respiratory arrest. Management: Symptomatic and supportive care. Provide patent airway with assisted or controlled ventilation, correct electrolyte and fluid imbalances; may perform gastric lavage and induce emesis (oral tab). Naloxone IV is used to reverse opioid effects but should only be given if there is significant respiratory or CV depression.
Additive sedative and respiratory depressive effects with benzodiazepines (e.g. alprazolam, clonazepam, diazepam) and other CNS depressants (e.g. chlorpromazine, oxycodone). Increased risk for serotonin syndrome with SSRIs (e.g. escitalopram, fluoxetine, sertraline), serotonin-norepinephrine reuptake inhibitors (e.g. venlafaxine, duloxetine, sibutramine), TCAs (e.g. amitriptyline, clomipramine, imipramine), triptans (e.g. sumatriptan, zolmitriptan, almotriptan), 5-HT3 receptor antagonists (e.g. ondansetron, granisetron) and other drugs affecting serotonin neurotransmitter system (e.g. mirtazapine, tramadol, trazodone). Increased risk of withdrawal syndrome with mixed agonist or antagonist (e.g. butorphanol, nalbuphine, pentazocine) and partial agonist (e.g. buprenorphine) analgesics. May increase the neuromuscular-blocking effect of muscle relaxants (e.g. baclofen, metaxalone). Decreased serum plasma concentration which may precipitate withdrawal syndrome when concurrently administered with CPY3A4 inducers (e.g. carbamazepine, phenobarbital, phenytoin, rifampin). May have an increased serum plasma concentration when given with aciclovir and cimetidine. May increase risk for urinary retention and constipation with anticholinergic drugs (e.g. atropine). May decrease the effect of diuretics (e.g. furosemide, hydrochlorothiazide). May reduce the plasma concentration of ciprofloxacin. Potentially Fatal: Increased risk of severe respiratory depression and serotonin syndrome if concurrently administered with or within 14 days of discontinuing MAOIs (e.g. isocarboxazid, linezolid, phenelzine, selegiline, tranylcypromine). Increased risk of opioid toxicity when concurrently administered with ritonavir.
Increased risk of CNS depression with alcohol. Increased risk of serotonin syndrome with St. John’s Wort.
Description: Pethidine is a phenylpiperidine derivative opioid analgesic. It acts mainly as a mu-receptor agonist. Like most opioid analgesics, it mimics endogenous opioids by activating opioid receptors in the central and peripheral nervous system. It reduces the release of neurotransmitter substances and also reduces the activity of postsynaptic neurons in the spinal cord, thus preventing transmission of the pain impulse.
Synonym: meperidine. Onset: Analgesia: 10-15 minutes (oral, IM, SC); approx 1-5 minutes (IV). Duration: Analgesia: Approx 2-4 hours. Pharmacokinetics: Absorption: Absorbed from the gastrointestinal tract. Rapidly absorbed after IM or SC inj. Bioavailability: Oral: Approx 50-60%; IM: Approx 80-85% (erratic and variable). Time to peak plasma concentration: Approx 1-2 hours (oral); 45 minutes (IM/SC). Distribution: Crosses the placenta, enters breast milk and present in CSF. Plasma protein binding: Approx 30-80% (variable). Metabolism: Metabolised in the liver via hydrolysis into pethidinic acid or via N-demethylation into norpethidine then via hydrolysis into norpethidinic acid and subsequently, via partial conjugation with glucuronic acid. Excretion: Via urine (mainly as metabolites, approx 5% as unchanged drug). Elimination half-life: Approx 3-6 hours (as unchanged drug): up to 20 hours (as norpethidine).
Oral solution, tab: Store at 25°C. Solution for inj: Store between 20-25°C.