Efficient prevention of adverse drug reactions (ADRs) requires knowledge about their severity and pharmacological mechanisms and is dependent on reliable data on their frequencies and possible risk factors. The study was conducted to investigate the prescribers' experience and understanding of the ADRs of psychotropic drugs, and their attitude towards reporting these. In a questionnaire, physicians treating adult psychiatric patients were asked which ADRs that they regarded bothersome for some of the most widely used antidepressants and antipsychotics. Questions about the relationship between blockade of drug receptors and ADRs, and about the physicians' personal experience of and attitudes towards reporting of ADRs were also included. In total, 70 of 91 questionnaires (78%) were returned. The mean number of ADRs regarded bothersome ranged from 2.4 to 9.3 for the various drugs/drug classes. Qualified psychiatrists stated a significantly higher number of bothersome ADRs than did the residents. The percentage of physicians associating blockade of a receptor with a specific ADR varied from 76% (histamine receptor blockade and sedation) to 37% (alpha(1)-adrenergic blockade and tachycardia). Thirty-nine per cent of the physicians had never reported an ADR to the Norwegian Medicines Agency. The number of ADRs considered bothersome was relatively high. The pattern of these ADRs generally mirrored the typical ADR profiles of the drugs. The knowledge of the underlying mechanisms of ADRs was more or less incomplete. The reporting rate of ADRs to the national regulatory authorities was low.
Rates of nonadherence during treatment with antipsychotics have been found to vary in a wide range from 20% to 90%. The aim of the present study was to investigate the influence of inpatient versus outpatient status on the adherence to treatment with olanzapine and clozapine. In the period from 1999 to 2007, olanzapine and clozapine were the 2 most frequently analyzed antipsychotics at the Department of Clinical Pharmacology at St. Olavs University Hospital, Trondheim, Norway, with more than 24,000 and more than 18,000 samples, respectively. In total, 111 patients on olanzapine and 95 patients on clozapine had provided samples in both the inpatient and outpatient settings and were included in the study. The primary outcome variable was the serum concentration-to-dose ratio (C/D ratio), that is, the serum drug concentration per milligram of drug given. For olanzapine, the C/D ratio in the outpatient setting was 10.7% lower than in the inpatient setting (P = 0.013). No such difference was found for clozapine. The difference in the olanzapine group was exclusively attributed to a lower outpatient ratio in females. For clozapine, no sex influence was found. No effect of age on the C/D ratios was found either for olanzapine or for clozapine. The lower C/D ratio in females using olanzapine in the outpatient setting might imply that they, in contrast to males, are less adherent to their medication when outside hospital. For clozapine, there were no indications of differences in adherence between inpatients and outpatients.