A single dose pharmacokinetic study of Gastrobid Continus and Maxolon in the perioperative period.

1. A single dose pharmacokinetic comparison of Gastrobid Continus and Maxolon was carried out perioperatively in two groups of 12 gynaecological patients; each group comprised six patients for major surgery and six patients for minor surgery. 2. The areas under the plasma drug concentration-time curves were similar after both preparations. 3. In the minor surgery group after Gastrobid Continus the plasma drug concentration-time curve was wider at half Cmax (P less than 0.01), Cmax was reduced (P less than 0.05) and delayed (median (range) 4 (3-6) vs 2.5 (2-4) h) compared with Maxolon, and the log of the metoclopramide concentration did not have a linear relationship with time from 2-9 h. 4. A flattening of the plasma drug concentration-time curve was the only difference between the two preparations in the major surgery groups. 5. The plasma drug concentration-time curve was wider (P less than 0.05) at at half Cmax in the minor compared with the major surgery groups receiving Gastrobid Continus. 6. Pharmacokinetic parameters were similar for Maxolon in both surgical groups. 7. Sustained release pharmacokinetic characteristics were most pronounced in the minor surgery group which did not receive opiate medication but in which there were more moderately anxious patients prior to induction and in whom anxiety may have delayed gastric emptying.