2. Pharmacokinetics, Pharmacodynamics, and Pharmacogenetics Flashcards
process of drug movement through the body that is necessary to achieve drug action
pharmacokinetics
4 processes of pharmacokinetics
- absorption
- distribution
- metabolism
- excretion
movement of the drug into the bloodstream
absorption
purpose of enteric coated drugs (EC)
resist disintegration in the gastric contents of the stomach (wait until small intestine)
T/F: enteric coated (EC) drugs and extended release (ER) drugs should not be crushed
True
Which route is going to be absorbed the quickest?
IV (already in the bloodstream); IM and subcutaneous will both be quicker than oral (enteral)
Which version of transport will be absorbed quicker: active or passive?
Passive; does not require molecules or energy -> can diffuse across membranes
What types of molecules cannot diffuse across membranes (passive)?
water-soluble and ionized (positively or negatively charged)
What types of molecules can diffuse passively across membranes?
lipid-soluble and nonionized
oral drugs pass from intestinal lumen to the liver via the portal vein and undergo metabolism -> reduces amount of active drug
first pass effect
percentage of administered drug available for activity
bioavailability
Factors that alter bioavailability
- drug form
- route of administration
- gastric mucosa and motility
- administration w/ food and other drugs
- changes in liver metabolism (liver dysfunction)
movement of drug from circulation to the body tissues
distribution
What occurs w/ drugs that are highly protein-bound?
less active drug available -> drug bound to protein is inactive
What is the effect of taking at least 2 meds that are both highly protein-bound?
both drugs will compete for protein binding -> higher free active drug -> may need smaller dose
What types of drugs are able to cross the blood brain barrier (BBB)
highly lipid soluble and of low molecular weight can cross by diffusion while other may cross via transport proteins
What is considered before giving drugs during pregnancy?
risk-to-benefit ratio
process by which the body chemically changes drugs into a form that can be excreted; aka biotransformation
metabolism
liver enzymes that covert drugs into metabolites
cytochrome P450 enzymes
time it takes for the amount of drug in the body to be reduced by half
half life
occurs when the amount of drug being administered is the same amount of the drug being eliminated
steady state (plateau drug level)
What is a loading dose?
a large initial dose of a drug w/ a long half life -> allows therapeutic effects to take place while reaching a steady state
elimination of drugs from the body
excretion
main route of drug excretion
kidneys
What must you be aware of when administering drugs?
renal lab values (will the drugs be excreted properly)