Pethidine

Introduction

Pethidine, is a synthetic opioid analgesic that acts mainly as a -opioid agonist. Pethidine is used for the relief of most types of moderate to severe acute pain including the pain of labour. It is more lipid soluble than morphine and has a less potent and shorter lasting analgesic effect; analgesia usually lasts for 2 to 4 hours. Its short duration of action and accumulation of its neurotoxic metabolite make it unsuitable for the management of chronic pain.

Generic Name 藥名	HA Code 藥物代碼	Classification藥物分類
Pethidine 1ml injection	PETH02	DD

Equivalent doses of opioid analgesics

Analgesic/Route	Dose
Codeine: PO	100 mg
Diamorphine: IM, IV, SC	3 mg
Dihydrocodeine: PO	100 mg
Morphine: PO	10 mg
Morphine: IM, IV, SC	5 mg
Oxycodone: PO	6.6 mg
Tramadol: PO	100 mg

Route of Adminstration	SC
	IV

Dosage

For moderate to severe acute pain:

Oral	50-150 mg every 4 hours if necessary
Subcutaneous or intramuscular	25-100 mg, then 25-100 mg after 4 hours
Intravenous	25-50 mg, then, 25-50mg repeated after 4 hours

In obstetric analgesia 50 to 100 mg may be given by intramuscular or subcutaneous injection as soon as contractions occur at regular intervals. This dose may be repeated after 1 to 3 hours if necessary up to a maxmum of 400 mg in 24 hours.

Doses in children

Oral or intramuscular	0.5 to 2mg/kg, repeated after 4 hours if necessary