The relationship between poor medication compliance and seizures.

Predictors and consequences of inadequate compliance with seizure medications were assessed using a 10-item postal survey. Dose omissions were reported by 71% of the 661 respondents (2+/-2 doses of seizure medications), with 45% of patients reporting a seizure after a missed dose, at some time during treatment. Dose omission was more likely with longer use of seizure medications (more than 5 years, P<0.01). Having seizures after missed doses was associated with number of seizure medication doses (P=0.04) and number of seizure medication tablets/capsules (P=0.01). Odds ratios showed that each increase in dose frequency (one, two, three, or four doses daily) increased the likelihood of a seizure after a missed dose by 36%. Taking larger numbers of tablets/capsules increased the odds of having a seizure after missed doses by 43%. These data provide evidence that medication compliance remains an important issue in epilepsy treatment.