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NERVOUS SYSTEM › ANALGESICS › OPIOIDS › Opioids in combination with antispasmodics
pethidine and antispasmodics
N02AG03
Forms & Strengths
- Fixed-dose combination tablets (pethidine hydrochloride + antispasmodic)
- Parenteral injection solution (pethidine hydrochloride + antispasmodic)
Adult Dosing
- Oral/Parenteral: 1 to 2 tablets or equivalent injection every 4 to 6 hours as needed for severe acute pain with visceral spasm
- Maximum daily dose limited by the pethidine and antispasmodic component toxicity thresholds
Pediatric Dosing
- Safety and efficacy not established in pediatric patients
- Use generally avoided in children due to high risk of pethidine metabolite toxicity and anticholinergic adverse effects
Indications
- Management of moderate to severe acute pain accompanied by visceral smooth muscle spasm
- Biliary and renal colic
Mechanism of Action
- Pethidine acts as a mu-opioid receptor agonist providing central analgesia
- Antispasmodic component (typically anticholinergic or musculotropic) relaxes visceral smooth muscle to relieve cramping
Contraindications
- Hypersensitivity to pethidine, antispasmodics, or any component
- Concomitant MAO inhibitor use or within 14 days of cessation
- Significant respiratory depression, acute or severe bronchial asthma
- Gastrointestinal obstruction, paralytic ileus, toxic megacolon
- Narrow-angle glaucoma, severe urinary retention, myasthenia gravis
Adverse Reactions
- Dizziness, sedation, lightheadedness, somnolence
- Nausea, vomiting, constipation, dry mouth
- Urinary retention, blurred vision, tachycardia
- Respiratory depression, confusion, hallucinations (risk of normeperidine toxicity with repeated dosing)
- Orthostatic hypotension
Drug Interactions
- Monoamine oxidase inhibitors (MAOIs): Risk of severe serotonin syndrome, excitation, or hyperpyrexia
- CNS depressants (alcohol, sedatives, hypnotics, general anesthetics): Enhanced central nervous system and respiratory depression
- Anticholinergic drugs:Additive anticholinergic side effects such as severe constipation, dry mouth, and urinary retention
- CYP3A4 inhibitors/inducers: Alter metabolism of pethidine and its active neurotoxic metabolite, normeperidine
Curated Content: Needs Vetting Before Put to Clinical Use