Pharmacokinetics of rectal tramadol in postoperative paediatric patients

Results. The pharmacokinetics of rectal tramadol could be adequately described by a onecompartment model. The pharmacokinetic parameters derived from the model indicate that a low variability was present. Elimination half-life was 4.3 (0.2) h (SEM) and the apparent clearance was 16.4 (1.5) litre h 1 (SEM). Conclusions. The study showed that after rectal administration, tramadol is absorbed at a reasonable rate and with a low inter-individual variability in small children. The data also suggested that a rectal dose of tramadol 1.5–2.0 mg kg 1 is therapeutic.