Week 4 Cardiac Pharmacology Flashcards
what is first pass metabolism
goal medications have to go through the intestinal epithelium and the portal venous system and the liver before they can enter the circulation. So, the drugs will undergo metabolism in the intestines and then has to be excreted into the intestines from the liver. All of this will decrease is bioactivity, and reduces the amount of drug that actually makes it to the systemic circulation.
what is half life
the time required for 50% of the first order process to complete. so this means that 50% of the drug is eliminated after one half life.
what does half life determine?
the time for the drug to disappear, and the the time we need to be able to dose the drug, and know what the plasma steady state is. Need to know how long it will last.
what is steady state
the amount of the drug administered per unit of time. like with an IV, the drug is at a steady state. oral administration, and taking it at the same time, ensures equal amounts in the system.
TF: there is a natural fluctuation in the amount of drugs in the system
true
how do oral and IV doses differ
oral doses have to be much larger, because they are metabolized before they enter the circulation. IV drugs need a much smaller dose
can nitroglycerine be orally administered?
no, because it is completely extracted before it reaches the circulation. it undergoes pre systemic metabolism, so you need to administer it either IV or under the tongue.
what is always present before the plasma drug concentration exceeds the minimum effective concentration of the desired effect
a lag period
what are the temporal characteristics of drug effects
you have a lag time, and then you have the response to the drug that you wanted. the response will build until you start to sag off, and then it disappears.
what is the difference between a selective and a non-selective drug
selective means it can only bind to one receptor, ad then a nonselective drug can bind to many areas, like EPI… which can attach in the lungs and the heart.
what is an agonist
binds to a specific membrane and activates the cell and opens membranes
what is an antagonist
binds specially, but blocks the agonist. Does not influence the cell function, but can block people out
what does a non-competitive antagonist do
binds to the allosteric (non-agonist) site on the receptor to prevent the activation of the receptor. it doesn’t compete, it just prevents action. binds to a different part.
what does a competitive antagonist do
binds to the same site as the agonist, but doesn’t activate it. it blocks. Cock block.
what side effect does beta blockers have that can affect PT
beta blockers reduce the HR at rest, and suppresses chronotropic responses to exercise.
when dealing with HTN, what is always our first treatment option
lifestyle modifications
when treating HTN, what is our goal BP
less than 140/90mmHg, or less than 130/80mmHg in people with diabetes or kidney disease.
what is the initial mediation for most HTN patients
thiazide type diuretics
what is the usual 2 drug combo for HTN
ACE inhibitor and thiazide diuretic
what is the goal of diuretics
decrease blood pressure by reducing the blood volume, via the kidneys.
what are the 3 most common types of diuretics
Loop (lasix)
Thiazide (hydrochorothiazide)
aldosterone receptor antagonists.
what do loop diuretics do
they block the Na/K/Cl reabsorption in the loop of Henle, they knock off a lot of volume, but also you lose a lot of Na and K
what patients get loop diuretics as a drug of choice
HF, CAD and CKD
what does thiazide do
blocks Na reabsorption int he distal tubule of the nephron
what does aldosterone receptor antagonists do
blocks aldosterone and interferes with Na/K exchange at the distal table.
what are the types of sympatholytics
beta blockers, and alpha 1 backers and alpha 2 agonists.