Medical pharmacology is primarily concerned with the mechanisms by which drugs treat disease processes， relieve symptoms， and counteract the molecular manifestations of disease. Pharmacology is also concerned with the factors that determine the time course of drug action， including drug absorption， distriburion， metabolism， and excretion.Students are often overwhelmed by the vast amount of
　　pharmacological information available today. This textbook provides the essential concepts and information that students need to be successfulin their courses without an overwhelming amount of detail.
　　This text is primarily intended for students who are taking their first course in pharmacology， but it will also be useful for those who are preparing to take medical board or licensing examinations. Because of the large number of drugs available today， this text emphasizes the general properties of drug categories and prototypical drugs. Chapters begin with a drug classification box to familiarize students with drug categories， subcategories， and specific drugs to be discussed in the chapter.
　　In the four years since the publication of the previous edition of Pharmacology by Brenner and Stevens， major trends in the development and marketing of new medications and new formulations were apparent. First， there was an explosion of combination drugs released onto the market in recent years. This is a good thing， as there is often pharmacological synergy between combined agents， but also because patient compliance is improved. It is easier to take one pill than two，or three， or four. The usual product combines two successful and effective single agents for the treatment of a disorder.These newly approved combination drugs are included in this 5th edition of Brenner & Stevens' Pharmacology.
　　Second， the market is flush with a number of new immunopharmacology products. Immunopharmacology is now a well-ripened field and the fruits of this discipline are apparent to both the physician and consumer by che new immunopharmacology drugs touted in TV commercials.
　　Pharmaceutical manufacturing of monoclonal antibodies that target receptors or other proteins is a rapidly growing sector of biologics. Many therapeutic classes of pharmacological agents now have one or two drugs that work via antibodies or that target immune system factors. This edition contains a number of such new immunopharmacology drugs. However，
　　the FDA approval of monoclonal antibody drugs and other biologics often comes with a number of serious warnings and adverse outcomes.
　　Third， during the last four years， the rampant use of pre-
　　scription opioids and the resultant opioid overdose epidemic were fully recognized. The appropriate response from the
　　pharmaceutical manufacturers was to develop new agents and formulations for the treatment of opioid dependence. The expanded class of these opioid medications is fully described in Chapter 23， \"Opioid Analgesic and Antagonists.\"
　　Fourth， the epidemic of type 2 diabetes across the USA，and the tremendous market for product， brought drug develop-ers back into the lab to work on antidiabetes medications.There were eight FDA-approved antidiabetes medications released into the market in the last two years. Many of these new medications target recently discovered mechanisms of action， like blocking sugar uptake at the kidneys. These new drugs and mechanisms of action for treating diabetes are updated in Chapter 35， \"Drugs for Diabetes.\"
　　The book now in your hands was extensively revised for the 5th edition to include all the new drugs on the market，and to exclude older drugs that were withdrawn from the market since the last edition of this textbook. The figures that were retained were updated and new figures added， with an emphasis on illustrating drug mechanisms of action. A modern graphic style was developed for the figures to improve understanding and to entice the eye.
　　The reader of this book will know some drugs better by their trade names. With the incessant marketing of new pharmaceuticals， many trade names of new drugs become common. As all medications are indexed under both their generic and brand name， this book is also a valuable reference for a quick review of drugs encountered in the reader's personal or professional life.
　　We thank our spouses and offspring for their encourage-ment and patience while we worked on this book. Much appreciation goes to our \"significant others\" （P <0.05） who both assisred with discussions of new drugs in their areas of expertise. However， any errors or typos are solely the respon-sibility of the authors. We also appreciate the fine people at Elsevier， who bring it all together to produce the nicely designed textbook now m your hands. The interactions with Lauren Willis （no relation to Bruce） and Rebecca Gruliow were especially professional and pleasant. They both seem to really know what they are doing.
　　Finally， we are pharmacologists who spent most of our careers at a university medical school. We are not physicians or medical consultants. Therefore none of the following text should be taken as medical advice.