Therapeutic monitoring of digoxin and antiepileptic drugs in Egypt and Saudi Arabia.

Retrospective analysis was undertaken of serum drug levels determined in 1996 of 580 Egyptian and 1299 Saudi samples and in 2001 of 2361 Saudi samples. Monitored drugs were digoxin, carbamazepine, phenytoin, and valproic acid. The therapeutic drug monitoring results in 1996 showed no differences between the two countries in the rates of subtherapeutic, therapeutic, or toxic drug levels. When the levels of all drugs relative to therapeutic ranges were compared between the 1996 and 2001 Saudi data, a significant decrease in the rate of potentially toxic levels was seen in 2001.