IMPAIRED ABSORPTION OF PARACETAMOL IN VEGETARIANS

1 The absorption and disposition of paracetamol was investigated in 10 healthy male Thai vegetarians and 10 similar non-vegetarians following an oral dose of 20 mg kg-1. 2 The absorption rate of paracetamol was significantly impaired in the vegetarians compared with the non-vegetarians as shown by a lower mean C(max) (11.7 +/- 1.4 vs 15.6 +/- 1.6 mg l-1, 95% confidence interval of the difference 2.49 to 5.36), increased t(max) (median 1.75, range 0.75 to 3 h compared with 0.75 and 0.25 to 2 h) and an increase in the time for input of 50% of the total amount absorbed (0.54 +/- 0.38 compared with 0.20 +/- 0.10 h: 95% confidence interval of the difference 0.063 to 0.61). 3 A significantly lower total 24 h urinary recovery of paracetamol and metabolites (72.1 5.4 vs 86.4 +/- 5.4% of the dose; 95% confidence interval of the difference 8.0 to 20.6) indicated a decrease in the extent of absorption in the vegetarians also, although the total AUC values did not differ significantly between the two groups. 4 The plasma paracetamol half-life. partial metabolic clearances and fractional urinary excretion of the glucuronide, sulphate, cysteine and mercapturic acid conjugates of paracetamol were similar in the vegetarians and non-vegetarians.