fa فراوانی تداخلات دارویی در بیماران بستری در سه بیمارستان شهر تهران General پژوهشي Research Article Background and Aim: Drug interaction includes the effect of a drug, food or anything that can induce changes in the pharmacokinetic or pharmacodynamic properties of a certain drug. The aim of the present study is to assess drug interactions of bedridden patients in three Tehran hospitals.   Materials and Methods: This retrospective research was accomplished on 400 bedridden patient’s dossiers in three hospitals of Tehran city at secondary half of 2006 year . Questionnaire was used according to Hansten classifications to gather information from available data.   Results: Dossiers assessment showed 1087 visits and 2610 drug order. 168 dossiers (42%) were found having drug-drug interactions (568 cases). Drug interactions were severe (4.4%), moderate (47%) and mild (48.6%). Antibiotics had the commonest (27.5%), while the neuroleptics and digitalis (0.5%) and bronchodilators (0.3%) brought about the least drug interactions.   Conclusion: Our findings showed that the drug prescription doesn't follow a correct logic and is still increasing in comparison to the past. Drug interaction,bedridden patients,Dossier 22 27 http://mcj.bums.ac.ir/browse.php?a_code=A-10-1-336&slc_lang=fa&sid=1 Ali Mohammad Alizadeh علی‌محمد علیزاده 10031947532846004460 10031947532846004460 Yes PhD of Physiology, Cancer Research Center, Cancer Institute, Tehran University of Medical Sciences, Tehran, Iran. Email: aalizadeh@razi.tums.ac.ir دکتری فیزیولوژی، دانشگاه علوم پزشکی تهران، مرکز تحقیقات سرطان. تلفن: 021-88029284 پست الکترونیک: aalizadeh@razi.tums.ac.ir Abdurrhman Rostamian عبدالرحمان رستمیان 10031947532846004461 10031947532846004461 No Assistant Professor, Faculty of Medicine, Tehran University of Medical Sciences, Tehran, Iran فوق تخصص، استادیار دانشکده پزشکی، دانشگاه علوم پزشکی تهران Khadijeh Saeedpour خدیجه سعیدپور 10031947532846004462 10031947532846004462 No Nurse, Tehran University of Medical Sciences, Tehran, Iran کارشناس پرستاری، دانشگاه علوم پزشکی تهران Mohammad Hemmati محمد همتی 10031947532846004463 10031947532846004463 No PhD Student, Faculty of Medicine, Tehran University of Medical Sciences, Tehran, Iran دانشجوی دکتری، دانشکده پزشکی، دانشگاه علوم پزشکی تهران Zahra Khorasani زهرا خراسانی 10031947532846004464 10031947532846004464 No Nurse, Tehran University of Medical Sciences, Tehran, Iran کارشناس پرستاری، دانشگاه علوم پزشکی تهران Mohammad Ali Mohagheghi محمدعلی محققی 10031947532846004465 10031947532846004465 No Associate Professor, Faculty of Medicine, Tehran University of Medical Sciences, Tehran, Iran فوق تخصص، دانشیار دانشکده پزشکی، دانشگاه علوم پزشکی تهران Minoo Khatami Moghaddam مینو خاتمی مقدم 10031947532846004466 10031947532846004466 No Pharmacist, Instructor, Faculty of Medicine, Tehran University of Medical Sciences, Tehran, Iran دکترای داروسازی، مربی دانشکده پزشکی، دانشگاه علوم پزشکی تهران Maryam Alsadat Mousavi مریم‌السادات موسوی 10031947532846004467 10031947532846004467 No Nurse, Tehran University of Medical Sciences, Tehran, Iran کارشناس پرستاری، دانشگاه علوم پزشکی تهران