Prevalence of the Coprescription of Clinically Important Interacting Drug Combinations Involving Oral Anticancer Agents in Singapore: A Retrospective Database Study Academic Article uri icon


  • BACKGROUND: There has been a recent increase in the availability and use of oral anticancer agents (OAAs). Drug-drug interactions (DDIs) involving OAAs pose a major concern in oncology practice due to these drugs' narrow therapeutic indices and potential for compromised efficacy and fatal adverse events. OBJECTIVE: To assess the prevalence of the coprescription of potentially interacting drug combinations involving OAAs in Singapore. METHODS: A retrospective review of physicians' electronic prescription records between the years 2007 and 2009 was performed in the largest cancer center in Singapore. An overall prevalence rate of potential DDIs and a prevalence rate for each individual DDI pair were calculated. Logistic regression was used to identify risk factors for potential DDIs. RESULTS: Fifty-eight clinically significant DDIs were selected for evaluation from Drug Interaction Facts and Micromedex DrugDex. A total of 39,772 OAA prescriptions prescribed to 8837 patients were reviewed. Potential DDI coprescription was found in 5.4% of the patients on OAAs and in 4.7% of the OAA prescriptions. The drug pair prescribed to the largest number of patients was prednisolone and aspirin. About half (53.3%) of the observed DDIs were found on the same prescription. On multivariate analysis, older patients, males, and those taking prednisolone had a higher risk for potential DDIs. CONCLUSION: Although limited by the data available, the analysis of prescription records found that ∼5% of patients taking OAAs in Singapore were exposed to ≥1 potentially interacting drug combination.


  • Ko, Yu
  • Tan, Sze-Ling Daphne
  • Chan, Alexandre
  • Wong, Yuet-Peng
  • Yong, Wei-Peng
  • Ng, Raymond Chee-Hui
  • Lim, Siew-Woon
  • Salim, Agus

publication date

  • August 2012

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