Background: Drug interactions continue to be an important cause of adverse effects, especially with cardiovascular drugs. Objective: This cross-sectional observational study aimed to recognize the frequency of potential drug-drug interactions (pDDIs) using three electronic knowledge bases (KBs); Lexicomp ® , Micromedex ® , and the free Drugs.com®, compare the inclusion and gradings of pDDIs in these three KBs and to identify associated risk factors. Methods: Medication orders of 125 patients in the cardiovascular department and its intensive care unit (ICU) of Assiut University Hospitals, Egypt were screened for pDDIs. Results: About 88.8% of the patients were prescribed five or more drugs. A sum of 1206 pDDIs was found which comprised of 245 different interacting pairs. Overall, 96.8% of the patients had at least

Are increasingly seen to be important, some drugs, can undergo direct physical or chemical interaction with other drugs and render both drugs inactive. In the light of the above, this study aims to examine some pharmaceutical studies of physicochemical drug interactions including solubility and adsorption studies of selected cardiovascular drugs which are commonly involved in potential drug-drug interaction (pDDIs) in the cardiovascular department in order to pave the path for preventing or at least reducing the incidence of pDDIs. To reach this objective, study encountered some practical consequences of the physical chemistry of drugs, especially their interactions with each other, or with various pharmaceutical adsorbents. The solubility of three cardiovascular drugs was tested in the presence of other drugs using the shake-flask method. Those drugs were: aspirin, furosemide and amiodarone. Our results showed that spironolactone can affect the hydrolysis of aspirin if co-administered at equivalent clinical doses, and therefore might reduce the efficacy of protective low-dose aspirin. Moreover, the solubility of furosemide decreased in the presence of gentamicin. .The solubility of amiodarone decreased in presence of warfarin, theophylline and lidocaine.In the adsorption experiments, aspirin and furosemide were selected as adsorbates: aspirin and furosemide. The adsorbents used were: activated charcoal, cholestyramine, kaolin, sodium hydroxide and sodium alginate. The experimental adsorption data were fitted to four isotherm models by both linear and non-linear regression analyses. Freundlich isotherm provided the best fit for most adsorption data followed by Temkin and Langmuir isotherms. The highest adsorption capacity of activated charcoal and cholestyramine was for furosemide.