Lecture

• For Geriatrics drugs have very slow absorption so the dose has to be increased to have the same therapeutic effect
• As we age. the intestinal tract has decreased blood flow, reduced surface area, decreased motility/gastric acid secretions. This results in slowed rate of absorption and slowed onset of drug action.
• The peak drug levels tend to decrease with age, small amount of drugs are absorbed over longer periods of time
• In geriatrics, lean body mass % decreases, body water % increases and body fat % increases; this means lipid soluble drugs have a wider distribution.
• Lipid soluble drugs having a greater distribution in geriatrics causes a slowed elimination, greater half life and greater duration of action
• For geriatrics, water-soluble drugs basically means more drug in less fluid because their water concentration is lower. This essentially means greater concentration of drugs in certain organs and greater effects
• Drug metabolism generally decreases with age as there's decreased blood flow to the liver.
• The mixed function oxidase system is part of the DMMS and it consists of the enzymes responsible for oxidizing drugs. It is strongly affected by the aging process
• Drugs excreted by the kidneys are greatly affected by the aging process because of decreased GFR and creatinine clearance. This means drugs have an increased DOA/plasma concentration/increased pharmacological action
• Thiazide and loop diuretics/beta blockers interfere with Diabetes by altering BGLs
• NSAIDs interefere with the effects of ACEIs and diuretics in the cases of hypertension
• Anticholinergics interfere with an enlarged prostate as it causes urinary retention