Absorption in the elderly
- decreased gastric acid production: causing impaired drug dissolution and decreased bioavailibility (Examples; erthyromycin, ketoconazole)
- decreased gastric motility: decreased drug absorption (example: vitamin b12 and calcium.
- Decreased small bowel surface area
- Decreased splanchnic blood flow:
- Reduced first pass metabolism: Increased absoprtion of high clearance drugs, decreased absorption of drugs from pro drugs
which can cause inccrease/ decrease plasma concentration resepctively.
drugs that would result in high levels: morphine, liodcaine, verapamil, propanolol, nitroglycerin.
drugs that would result in low plasma levels; catopril, prednisone, clopidogrel.
Distribution in the elderly
- increased body fat: causing an increased distribution of lipid soluble drugs such as macrolides, benzodiazepeines, amiodarone, morphine. Prolonged effects after stopping the drug.
- decreased lean body mass and TBW: causing decrease distribution od water soluble drugs. For frugs like digoxin, lithium, gentamicin, penicillin, theophylline.
- malnutrition/proteinuria that can lead to hypoalbuminaemia: causing increased concentration fo free drugs- causing increased drug toxicity
Metabolism in the elderly
- liver disease: can cause reduced heaptic blood flow and function
- as well as decreased cytochrome p450 activity.
examples: opioids, metoclopramide, lidocaine, propanolol, enlapril, perinodopril.
Elimination in the elderly
Decreased renal function and GFR
decreased drug removal
increased risk of toxicity
example: digoixin, lithium, gentamicin, ACE inhibitors.
CWDPLTI
Carefully: cabamazepine
watch: warfarin
drugs: digoxin
posessing: phenytoin
low: lithium
therapeutic: theophylline
index: immunosuppressants
whats better than morphine for renal impariment
fentanyl
examples of drugs affected by low albumin levels
furosemide, cimetidine, warfarin
is co-trimoxazole good or nah
Drug-induced blood disorder risk is higher
* Choose alternative if possible
* Can cause bone marrow suppression
examples of glucocorticoids
beclomethasone, prednisolone
- they can increase the air way calibre in astma
- reduce bronchial inflmaation reactions such as oedema and mucus hypersecretion
- and can modify allergic reactions
what drug is for over reactive baldder
tolterodine (anti-muscarinic)
