Evaluation of Pharmacokinetic Drug Interactions in Prescriptions of Intensive Care Unit (ICU) in a Teaching Hospital

Concomitant use of several drugs by ICU( Intensive Care Unit) patients is often unavoidable. In these patients, pharmacokinetic drug interactions are very likely. The current study was designed to evaluate these interactions in patients hospitalized in an ICU of a teaching hospital in Tehran, Iran.A questionnaire was designed and used to collect study data. The study was done in the ICU of a teaching hospital affiliated to the Shaheed Beheshti Medical University. Overall information extracted from 567 ICU prescriptions from March 2005 to December 2005. The extent of occurrence and frequency of potential pharmacokinetic interactions were categorized based on the reference text Drug Interactions Facts. All of the pharmacokinetic drug interactions were extracted and evaluated in terms of mechanism, significance, severity, documentation and onset.There were 413 pharmacokinetic interactions in 567 studied prescriptions, which were divided into 64 types of pharmacokinetic interactions. The most observed interaction was between ciprofloxacin and sucralfate. Mechanisms of the pharmacokinetic interactions were related to metabolism (%60.05), absorption (% 38.26), elimination (%0.97) and distribution (%0.73). There was a direct relationship between the number of drugs per prescription and the frequency of pharmacokinetic interactions (p<0.001, r =0.98) Findings obtained in this study revealed that there is a significant number of rapid occurring, moderate, probable and definite interactions among the ICU prescriptions. This highlights the necessity for the presence of a drug specialist (i.e. clinical pharmacist) to rationalize the therapy and minimize major interactions.