The Median Effective Dose (ED50) of Paracetamol and Morphine : A Study of Interaction Study

The Median Effective Dose (ED50) of Paracetamol and Morphine for Postoperative Patients: A Study of Interaction.

The aim of our study is to define the median effective analgesic doses (ED50) of paracetamol, morphine, and their combination and determination the nature of their interaction administered IV for postoperative pain after moderate painful surgery using up-and-down and isobolographic methods.

Ninety patients scheduled to undergo moderately painful surgery were included in one of three groups. Determination of median effective (ED50) doses was performed by the Dixon and Mood up-and-down method. Initial doses were 1.5g and 5mg, with dose adjustment intervals of 0.5g and 1 mg, in the paracetamol and morphine groups, respectively. The initial doses of paracetamol and morphine were 1.5g and 3mg, respectively in the paracetamol-morphine combination group with dose adjustment intervals of 0.25g for paracetamol and 0.5mg for morphine. Analgesic efficacy was defined as a decrease to less than 3 on a 0-10 numeric pain scale, 45 min after the beginning of drug administration. Isobolographic analysis was used to define the nature of their interaction.

initial doses was 1.5g g, with dose adjustment intervals of 0.5g . with maximum dose 2.5 g as an only starting dose / 24 h

The initial doses of paracetamol and morphine were 1.5g and 3mg, respectively in the paracetamol-morphine combination group with dose adjustment intervals of 0.25g for paracetamol and 0.5mg for morphine.

initial doses was 1.5g, with dose adjustment intervals of 0.5g . with maximum dose 2.5 g as an only starting dose / 24 h

The initial doses of paracetamol and morphine were 1.5g and 3mg, respectively in the paracetamol-morphine combination group with dose adjustment intervals of 0.25g for paracetamol and 0.5mg for morphine.

the aim of our study is to define the median effective analgesic doses (ED50s) of paracetamol, morphine, and their combination to determine the nature of their interaction administered IV for postoperative moderately painful surgery using the Dixon and Mood up-and-down method and isobolographic analysis.

the aim of our study is to define the median effective analgesic doses (ED50s) of paracetamol, morphine, and their combination to determine the nature of their interaction administered IV for postoperative moderately painful surgery using the Dixon and Mood up-and-down method and isobolographic analysis.

Inclusion Criteria: ASA physical status І or ІІ Moderately painful surgery patients postoperative pain more than 3 on a numerical pain score (NPS) - Exclusion Criteria: contraindication to the use of paracetamol and morphine Pregnancy age younger than 18 yr patient weight less 65kg intra-operative regional anesthesia, intra-operative administration of analgesics other than fentanyl, postoperative pain less than 3 on a numerical pain score (NPS)

Zeidan A, Mazoit JX, Ali Abdullah M, Maaliki H, Ghattas T, Saifan A. Median effective dose (ED(5)(0)) of paracetamol and morphine for postoperative pain: a study of interaction. Br J Anaesth. 2014 Jan;112(1):118-23. doi: 10.1093/bja/aet306. Epub 2013 Oct 24.