The Knowledge of Drug Interactions by Third Year Pharmacy Students at Two Western Schools of Pharmacy

Abstract

Objective: To determine the degree of knowledge of clinically significant drug-drug interactions by third-year pharmacy students at two schools of pharmacy located in the Western U.S., hereafter referred to as School A and School B. The purpose was also to determine if the degree of knowledge of drug interactions was related to the amount of work experience as well as exposure to drug interaction information in the curriculum of the pharmacy school at which these students are completing their degrees. The hypothesis of this study was that there would be no difference in knowledge of clinically significant drug-drug interactions by pharmacy students at School A and School B. Methods: A two-page questionnaire was distributed to third year pharmacy students at School A and School B. The first page of the questionnaire contained 10 questions on potential drug-drug interactions and asked the students to indicate if an interaction was present and also rank their confidence for the response provided to the interaction question using a scale of 0 (not confident) to 10 (very confident). For each drug-drug pair, there were three response choices: (A) Should not be used together-contraindicated, (B) May be used together with monitoring, and (C) May be used together without monitoring. The second page of the questionnaire requested information regarding demographics such as age, gender, whether or not the students currently work in a pharmacy setting outside of pharmacy school and if they do, which pharmacy setting and for how many years, where the students believe most of their knowledge regarding drug-drug interactions is from, whether the students would like to have more class-time dedicated to drug-drug interactions, and asked the students’ opinion of how important it is for pharmacists to be aware of drug-drug interactions. In order to determine whether or not exposure to drug interaction information during the curriculum affected the degree of knowledge of drug interactions, a survey of the amount of time devoted to drug-drug interactions during pharmacy school was given to a representative from each school. This survey asked whether or not the curriculum at the particular school had a required course that was in whole or part specific to drug-drug interactions, how many hours were devoted to drug-drug interactions in Therapeutics, Pharmacology, Medicinal Chemistry, and other non-elective courses, and asked for an estimated total number of hours devoted to drug-drug interactions during pharmacy school. Results: A total of 182 students completed and returned the questionnaire, 68 from School A and 114 from School B. There was no significant difference regarding the knowledge of DDIs between students at School A versus School B. The average (SD) number of drug interaction questions answered correctly was 54% (±17%) correct and 56% (±15%) correct respectively. There was no significant difference in subject characteristics including mean age, gender, and type of pharmacy-related work experience between the schools. The results of the survey indicated that the majority of students at both schools work in a community setting for a pharmacy- related job (58 students (88%) and 94 students (75%) for Schools A and B, respectively). A regression analysis showed that student confidence in their ability to correctly identify interactions was the only significant predictor of DDI knowledge (p=0.0138). However, there was only a weak correlation found between correctly answered questions and confidence in the ability to answer the question correctly (r = 0.22). The majority of subjects at both schools indicated that more time should be devoted to DDIs and that DDI information is very important. Conclusion: The study found that third year pharmacy students correctly identified approximately 55% of the drug-drug interactions. There was no significant difference in drug-drug interaction knowledge between the two schools surveyed. In addition, there was only a weak correlation between drug interaction knowledge and the student’s in their ability to correctly identify interactions. After controlling for age, gender, and work experience, we found that confidence was the only significant predictor of DDI knowledge. The majority of the students at both schools believe that drug-drug interaction knowledge is very important and that there should be more exposure to drug-drug interaction information throughout their curriculum. Future studies that survey drug-drug interaction knowledge at more schools may be warranted in order to incorporate changes in curriculums that will further develop the knowledge of drug-drug interactions in future pharmacists.