tailieunhanh - Section V - Drugs Affecting Renal and Cardiovascular Function

Diuretics increase the rate of urine flow and sodium excretion and are used to adjust the volume and/or composition of body fluids in a variety of clinical situations, including hypertension, heart failure, renal failure, nephrotic syndrome, and cirrhosis. The objective of this chapter is to provide the reader with unifying concepts as to how the kidney operates and how diuretics modify renal function. The chapter begins with a description of renal anatomy and physiology, as this information is prerequisite to a discussion of diuretic pharmacology | Arrhythmias can range from incidental, asymptomatic clinical findings to life-threatening abnormalities. Mechanisms underlying cardiac arrhythmias have been identified in cellular and animal experiments. In some human cases, precise mechanisms are known, and treatment targeted against those mechanisms can be used. In other cases, mechanisms can be only inferred, and the choice of drugs is based largely on results of prior experience. Antiarrhythmic drug therapy can have two goals: termination of an ongoing arrhythmia or prevention of an arrhythmia. It is now well recognized that antiarrhythmic drugs not only help to control arrhythmias but also can cause them, especially during long-term therapy. Thus, prescribing antiarrhythmic drugs requires that precipitating factors be excluded or minimized, that a precise diagnosis of the type of arrhythmia (and its possible mechanisms) be made, that the prescriber has reason to believe that drug therapy will be beneficial, and that the risks of drug therapy be minimized.