engleski

The prevalence of potential drug interactions in hospitalized patients

Aims: The increased prevalence of multidrug therapy, especially in elderly, enhances the risk of drug interactions leading to inefficacy or adverse drug reactions. Since there is no data on the frequency of clinically relevant drug interactions in hospitalised patients (pts) in Croatia, we conducted a study in two Hospital Centres (Rijeka and Zagreb) to evaluate the prevalence of simultaneous prescribing of Drug Combinations Prone to Interact (DCPI). Methods: We conducted a cross sectional study that included all pts hospitalised at the Department of Medicine on the day of the study. Demographic data, comorbidities, renal and hepatic function, generic names of drugs and daily dosage, were assessed for all hospitalised patients receiving  1 drug. Data were analysed for 202 predefined Drug Combinations Prone to Interact (DCPI). A rating scale ranging from 1-4 was used to indicate clinical relevance of a possible interaction (1-contraindicated ; 2-avoidable ; 3- consider risk-benefit ratio ; 4- hardly avoidable). Results: Overall, possible interactions were evaluated in 393 pts, of whom 174 (44.2%) were exposed to drug interactions. UHC Zagreb: Out of 176 patients, 168 were prescribed between 1-16 drugs (mean 6.27 ; SD 3.72). Out of 202 predefined DCPIs, 77 occured between 1-16 times. The total number of DCPIs was 200, which included 7 (3.5%) contraindicated combinations. DCPIs occured in 74/168 pts (44.1%). In 43/74 pts (58.1%) multiple DCPIs occurred. The most frequently drug pairs were: furosemide/corticosteroids, fluconazole/corticosteroids, furosemide/ACE inhibitors, LMWH/NSAR, etc. UHC Rijeka: 225 patients were prescribed between 1-14 drugs (mean 5.84, SD 2.69). Out of 202 predefined DCPIs, 71 occurred between 1-12 times. The total number of DCPIs was 287, which included 10 (3.5%) contraindicated combinations. DCPIs occurred in 100/225 pts (44.4%). Multiple DCPIs occurred in 62/100 pts (62.0%). The most frequently drug pairs were: furosemide/corticosteroids, furosemide/ACE ihibitors, diuretics/teophylline, LMWH/ASK, teophylline/H2-receptor blockers, etc. There was no statistically significant difference in the mean number of drugs prescribed, overall number of DCPIs and frequency of multiple DCPIs between the two Hospital Centres. Conclusion: The knowledge and alertness of the prescribing physician is important in avoiding potential hazardous adverse drug reactions. This is especially important in the hospital setting due to more drugs prescribed per patient and more vulnerable patient population. Our study indicates high prescription rate of DCPIs in the hospital setting. The prevalence assessment of clinically observable drug interactions is planned as the next step in our research. Evaluation of the prevalence of prescribing DCPIs could be a valuable tool in assessing how frequently clinically relevant drug interactions could be expected.

drug interactions; hospital

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