Potential drug-drug interactions and adverse drug reactions in dermatological inpatients.

OBJECTIVES: To present information on the frequency of drug-drug interactions and adverse drug reactions, and to provide assistance on how to minimize these major problems in the pharmacological treatment of dermatological inpatients.

PATIENTS AND METHODS: The medications given to 1,099 dermatological inpatients were retrospectively analyzed for drug-drug interactions and adverse drug reactions using web-based drug interaction software (Diagnosia® Check).

RESULTS: We report an overall frequency of relevant drug-drug interactions of 51.7 %, with an average of 3.2 interactions per affected inpatient. Drug combinations that should have been avoided were found in 5.7 % of the study population. Total drug count was the most important risk factor. Drug groups involved in the majority of interactions were analgesics, cardiovascular and antithrombotic agents, as well as antidepressants. The risk of developing adverse drug reactions was rated as "high" in 53.1 % of inpatients. The top five adverse reactions in this patient group were bleeding, constipation, anticholinergic effects, sedation, and orthostatic effects.

CONCLUSIONS: Potential drug-drug interactions as well as adverse drug reactions are alarmingly common in dermatological inpatients. Every other patient is at risk of experiencing such interactions or adverse reactions, and every twentieth patient receives a drug combination that should not be administered. Increased alertness is a must in order to identify patients at risk.