Serum 5'-nucleotidase in patients receiving anti-epileptic drugs.

Alkaline phosphatase (ALP), 5'-nucleotidase (5NT), and gamma-glutamyltransferase (GGT) were measured in sera from 335 adult and 93 pediatric inpatients receiving anti-epileptic drugs (AEDs). Among adults, 18 took only phenobarbital, 39 only carbamazepine, 159 only phenytoin, and 99 phenytoin with other AEDs. Of 93 children, 49 took phenytoin, and 44 took another AED. Among the 335 adults, only 118 had normal enzymes, but 316 had 5NT and ALP, each less than two times and GGT less than five times normal limits. Of 19 patients outside these ranges, 14 had either historic, physical, or biochemical evidence of liver or severe multisystem disease. The authors observed that the frequency of enzyme elevations in adults receiving AEDs was lower for 5NT (23%) than for GGT (54%) but similar to ALP (27%). The degree of elevation was also lower for 5NT and ALP than for GGT. Phenytoin was associated with the most frequent and highest enzyme elevations in both adult and pediatric patients. Consideration of these data is necessary in the evaluation of liver function in patients receiving AEDs.