Altered pharmacokinetics of lignocaine after epidural injection in type II diabetics

The pharmacokinetics of lignocaine has been compared after epidural anaesthesia in diabetics and non-diabetic patients. Epidural lignocaine 8 mg.kg-1 was given to 8 well controlled Type II diabetic and 8 non-diabetic patients and the plasma drug concentration in serial blood samples were measured by HPLC. The plasma level of lignocaine was lower in diabetics compared to non-diabetics. The peak level was attained at 20 min in both groups. The clearance of the drug was significantly higher, (39.9 vs 16.7 ml.min-1.kg-1) associated with a decreased elimination half-life and mean residence time. The study suggests that the rate of absorption of lignocaine is not altered after epidural administration and that its hepatic metabolism is increased in diabetics compared to non-diabetics.