Drug reference

pethidine

Drug monograph

CDSCO approved

EXCRETION

—

not curated

INTERACTIONS

12 major

incl. contraindicated

PREGNANCY

—

not curated

Top interactionssee all 12 →

AminophyllineContraindicatedTextbookKDT 7e · p227
ChlorpromazineSevereTextbook-citedKDT 7e · p950
DiazepamSevereTextbook-citedKDT 7e · p950
ImipramineSevereTextbook-citedKDT 7e · p950

Mechanism

Not yet extracted

Indications

analgesic (substitute of morphine)preanaesthetic medicationcontrol shivering (during recovery from anaesthesia or that attending i.v. infusions)preferred opioid analgesic during labour

Dosing

Adult: 50–100 mg i.m., s.c. (may cause irritation, local fibrosis on repeated injection). Occasionally given orally or i.v.

Pharmacokinetics

Half-life

The plasma t½ of pethidine is 2–3 hours.

Bioavailability

Pethidine exhibits high first-pass metabolism.

Protein binding

Not specified in text

Metabolism

Pethidine is hydrolyzed.

Contraindications

Avoid in renal failure
renal failure patients given repeated doses (prone to experience excitatory effects)
patients receiving nonselective MAO inhibitors
patients receiving selective serotonin reuptake inhibitors (SSRI)

Side effects

Common

similar to morphine except less marked spasmodic action on smooth musclesless prominent miosisless prominent constipationless prominent urinary retentionsome atropinic effects (dry mouth, blurred vision, tachycardia)tachycardia (due to antimuscarinic action)less histamine releasesedativeeuphoriant

Serious

seizures (due to accumulation of nor-pethidine metabolite)
muscle twitching (due to accumulation of nor-pethidine metabolite)
excitatory effects in overdose (tremors, mydriasis, hyperreflexia, delirium, myoclonus and convulsions) due to accumulation of norpethidine
neonatal respiratory depression (significant even at equianalgesic doses)
local irritation and fibrosis on repeated i.m. or s.c. injection

Drug interactions

Aminophylline

Contraindicated

Textbook

Should not be mixed in the same infusion bottle/syringe.

Do not mix.

Source: KDT 7e · p227

Chlorpromazine

Severe

Textbook-cited

Severe sedation and respiratory depression

Avoid concurrent use

Source: KDT 7e · p950

Diazepam

Severe

Textbook-cited

Excessive sedation, respiratory depression, motor impairment.

Avoid concurrent use

Source: KDT 7e · p950

Imipramine

Severe

Textbook-cited

Severe sedation and respiratory depression

Avoid concurrent use

Source: KDT 7e · p950

Dapoxetine

Severe

Textbook

May produce the ‘serotonin syndrome’.

Avoid combining pethidine with SSRIs.

Source: KDT 7e · p475

Escitalopram + Clonazepam

Severe

Textbook

May produce the ‘serotonin syndrome’.

Avoid combining pethidine with SSRIs.

Source: KDT 7e · p475

Maoi Inhibitors

Severe

Textbook

Norpethidine (an excitant metabolite) is produced in excess, leading to excitement (tremors, mydriasis, hyperreflexia, delirium, myoclonus, convulsions).

Avoid combining pethidine with nonselective MAO inhibitors.

Source: KDT 7e · p475

Alprazolam

Severe

Database

Drug interaction classified as: synergy.

Source: DDInter

Alvimopan

Severe

Database

Drug interaction classified as: synergy

Source: DDInter