Pharmacology Flashcards
Pharmacology two aspects
Pharmacokinetics - routes and actions
Pharmacodynamics- therapeutic and unwanted effects
Also
Pharmacognentics
Routes available
Oral Subcutaneous Intramuscular Intravenous Subdermal Rectal Sub lingual transdermal
Compliance / concordance
Some elderly patients are actually too compliant
But is estimated to be approx 50% on average
Can they read label
Can they open the pot
Are they able to swallow it
Regimen can be very complex
Liquids more prone to waste
Problems with sugar and dental health
Pharmacokinetics
Swallow the drug
Arrives in stomach
Moves into small intestine
Brakes proteins down to components molecules- nutrients
Digestion’s
Acidic environment in stomach
Digestive enzymes in duodenum
Will destroy any protein based drug
Completion of first pass metabolism
Absorption
Liver
Cytochromes P450s
Liver
Hepatic portal vein transfers drug to liver
Cytochrome P450s will start to brake down any drug
Potential for enzyme induction and tolerance
Changes in GI tact + changes in liver = first pass metabolism
Is only experienced by oral drugs all systemic drugs undergo second pass metabolism
Distribution
Systemic circulation
Bound to plasma proteins
Free dissolved in plasma
Binds to receptor site
Metabolism
Brake down of drug usually takes place in the liver- second pass metabolism
Hydrogenated then so more water soluble
Therefore more likely to be removed by kidney
Some into bile small intestine
2nd pass metabolism
Transferred to bile
Enters kidney filtrate
Into small intestines
Excreted in urin
Reabsorption
Elimination
Needs to be in bound from receptor, usually by whole drug receptor complex being taken into the cell and lysozyme separating them - receptors re cycled back to membrane drug expelled in active form
Kidneys unchanged rate
Reduced until 5 years and age related decline
Acute illness can lead to rapid decline in renal clearance and toxicity
