Actual versus prescribed timing of lovastatin doses assessed by electronic compliance monitoring.

The objective of the study was to compare compliance with and the hypocholesterolaemic effect of lovastatin given once daily as a morning or an evening dose. Twenty-four out-patients with familial hypercholesterolaemia were randomly assigned to receive placebo first, then lovastatin 20 mg, to be taken once daily for 4 weeks, either with the breakfast or evening meal, in a single-blind fashion. Drug compliance was assessed by pill counts and continuous electronic monitoring. Two compliance parameters were evaluated, consumption, defined as percentage of prescribed doses taken, and time compliance, the percentage of total dosing events recorded within defined intervals (6.00-10.00 h, and 17.00-21.00 h), for the morning and evening regimes. Both regimes satisfactorily reduced the total and LDL-cholesterol concentrations, and there was no significant difference in the extent of the reductions. Pill counts overestimated compliance, as revealed by the monitoring method. The times of actual consumption of doses by the patients often differed from that prescribed, predominantly in patients who were told to take the evening dose. Partial time compliance may have confounded the efficacy of the drugs. Electronic compliance monitoring appears to be particularly useful in chronopharmacological studies.