NUTR 3150 Lecture Notes - Lecture 15: Beta Blocker, Benzodiazepine, Phenytoin
24 Jul 2018
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Document Summary
Pharmacokinetics: pharmacokinetics= what the body does to the drug, as we age , absorption. Increased gastric ph with age can cause early release of enteric coated drugs: reduced liver mass and blood flow increases the bioavailability of some drugs, calcium channel blockers, tricyclic antidepressants, propranolol, distribution. Increased body fat prolongs half-life of lipophilic (fat-soluble) drugs. Diazepam, amitriptyline: decreased body water increases serum concentration of water soluble drugs. Increased risk of toxicity with decrease in serum albumin: metabolism, reduced hepatic volume and blood flow reduced metabolism by the cytochrome p-450 enzyme system, clearance may decrease by 30-40% Diazepam, metoprolol, phenytoin: renal elimination, age-related decreases in glomerular and tubular function of the kidneys cause decreases in the rate of elimination of many drugs. Less effect- beta blockers d/t down regulation of beta-receptors with aging. This includes non-prescription antihistamines used to relieve allergies, aid sleep or relieve cold symptoms: as age increases, acetylcholine decreases and cells may have fewer receptors for acetylcholine.
