title: A study of pethidine kinetics and analgesia in women in labour following intravenous, intramuscular and epidural administration.
abstract: 1 Epidural administration of opiates for analgesia has recently generated widespread interest and would theoretically be advantageous as a method for relief of pain in labour. 2 Plasma pethidine concentrations were measured after intravenous, intramuscular and epidural administration of pethidine to women in labour and after epidural administration to non-pregnant female surgical patients. 3 Kinetic parameters were derived from the plasma concentration data in each group of subjects and the relationship between plasma kinetics and analgesia in labour were examined. 4 Absorption of pethidine from the epidural space in pregnant women in rapid and excepting the lower initial values, the average plasma concentration and area under the plasma concentration v time curve did not differ significantly (P less than 0.01) from those obtained with intravenous dosage, but were significantly higher (P less than 0.01) during the first 2 h after dosage than the results after intramuscular administration. The analgesia provided by the epidural route of administration was greater than with intravenous or intramuscular administration. 5 It is postulated that the analgesic efficacy of epidural pethidine in women in labour is due to a combination of systemic and local effects and that the local effect is attributable to the local anaesthetic properties of pethidine rather than a selective anti-nociceptive action on the spinal cord.
mesh_terms: D000767:Anesthesia, Epidural; D000771:Anesthesia, Intravenous; D000773:Anesthesia, Obstetrical; D005260:Female; D005312:Fetal Blood / Q000378:metabolism; D006801:Humans; D007273:Injections, Intramuscular; D007700:Kinetics; D007743:Labor, Obstetric; D008614:Meperidine / Q000097:blood; D011247:Pregnancy
chemical_list: D008614:Meperidine