Adverse effects from the circadian fluctuations of carbamazepine plasma levels

In children on carbamazepine therapy who were complaining of tiredness it was proposed that the considerable plasma drug level variation over the day could explain this side effect. In spite of a "normal" fasting level the plasma drug level 2-4 hours after drug intake was well above the upper recommended therapeutic level. It is recommended that the time of sampling should be taken into account in carbamazepine drug monitoring.