Serum drug concentrations after oral administration of paracetamol to patients with surgical resection of the gastrointestinal tract.

Serum concentrations of paracetamol were measured at 30, 60, 120 and 180 min after oral administration of a solution of 1500 mg paracetamol in normal subjects (n = 32) (Group A) and in patients with total gastrectomy (Roux-en-Y reconstruction) (n = 5) (Group B), distal partial gastrectomy (Billroth I reconstruction) (n = 7) (Group C), pylorus preserving pancreatoduodenectomy (Billroth I type reconstruction) (n = 12) (Group D), and short bowel syndrome (n = 5) (Group E). In Group B, the dose was delivery directly into the jejunum 20 cm distal to the duodenojejunal flexure. The highest serum drug concentrations were observed in the 30 min sample in Groups B and C and in the 120 min sample in Groups A, D, and E. Mean (+/- s.d.) concentrations at these times were 18.90 +/- 1.55 micrograms ml-1 (Group B), 12.89 +/- 2.12 micrograms ml-1 (Group C), 11.12 +/- 3.16 micrograms ml-1 (Group A), 9.78 +/- 2.85 micrograms ml-1 (Group D), and 4.89 +/- 1.96 micrograms ml-1 (Group E), respectively. We conclude that in patients with normal intact gastrointestinal tract, most of a dose of oral paracetamol is absorbed from the jejunum distal to the duodenojejunal flexure.