Inert ingredients in drug formulations: influence on drug prescribing among medical doctors in Zagreb

Introduction: Inert (inactive) drug ingredients themselves may be associated with induction of allergic and toxic reactions, and could potentially induce adverse drug reactions. The knowledge of medical doctors from Zagreb about inert drug ingredients and its influence on the selection of pharmaceutical drug formulation in medical practise were investigated. Material and Methods: In this pilot study, an anonymous, voluntary-based questionnaire was distributed among 250 medical doctors from Zagreb (Croatia), 39% of them with MD degree only, and the rest of 61% specialists of general, internal and paediatric medicine; 51% and 49% of them worked in hospitals and primary care units, respectively. Results: More than a half (59%) of the participants estimated their knowledge about excipients as poor, 36% as good, and 5% as very good; 78% of the participants thought that medical doctors should get additional education on excipients. Information about all, active and inactive, drug compounds in hospitals and primary care units were available to 54% and unavailable to 31% of the participants, while 15% did not know if such information was available. Approximately 25% of the participants gave priority to the composition of both active and inert drug compounds when prescribing a particular pharmaceutical drug formulation. As many as 87% of the participants had patients who had rarely (55%) or often (32%) experienced variable tolerance to different pharmaceutical formulations of the same drug. Conclusion: More attention should be paid to the inert drug ingredients in drug prescribing and physicians' education.