drug therapy across lifespan- pharm

Assess patients response frequently observe for signs

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Unformatted text preview: are worse than the disease. • Choose nondrug therapies when possible. • Assess patient’s response frequently--observe for signs of accumulation. • Monitor hydration. • Consider drug holidays from time to time. 36 Absorption Altered GI absorption is not a major factor in drug Altered sensitivity. sensitivity. Percentage of an oral dose that is absorbed does not Percentage change with age. change Rate of absorption may slow. Delayed gastric emptying and reduced splanchnic blood Delayed flow occur. flow 37 Distribution Increased percentage of body fat • Storage depot for lipid-soluble drugs Decreased percentage of lean body mass Decreased total body water • Distributed in smaller volume; thus concentration is increased and Distributed effects are more intense effects Reduced concentration of serum albumin • May be significantly reduced in the malnourished • Causes decreased protein binding of drugs and increase in levels Causes of free drugs of 38 Metabolism Hepatic metabolism declines with age. Reduced hepatic blood flow, reduced liver mass, and Reduced decreased activity of some hepatic enzymes occur. decreased Half-life of some drugs may increase, and responses are Half-life prolonged. prolonged. Responses to oral drugs (those that undergo extensive Responses first-pass effect) may be enhanced. first-pass 39 Excretion Renal function undergoes progressive decline beginning in Renal early adulthood. early • Reductions in renal blood flow, GFR, active tubular secretion, Reductions and number of nephrons and Drug accumulation secondary to reduced renal excretion Drug is the most important cause of adverse drug reactions in the elderly. the 40 Excretion Renal function should be assessed with drugs that are Renal eliminated primarily by the kidneys. eliminated In elderly patients: In • Use creatinine clearance, not serum creatinine, because Use not lean muscle mass (source of creatinine) declines in parallel with kidney function. with • Creatinine levels m...
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This document was uploaded on 03/25/2014.

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