˚₊‧ʚ♡ɞ‧₊˚ 𝙿𝚑𝚊𝚛𝚖𝚊𝚌𝚘𝚕𝚘𝚐𝚢 ˚₊‧ʚ♡ɞ‧₊˚ Flashcards
what is the difference between Pharmacokinetics and Pharmacodynamics?
Pharmacokinetics is what the body does to the drug, while Pharmacodynamics is what the drug does to the body.
if a drug is administered topically, how might it be absorbed?
move through the skin or mucous membrane to reach the bloodstream.
if administered orally, how will the drug be absorbed?
Through the lining of the stomach or intestines.
slower with food
what is bioavailability?
(*hint: proportion of a drug that is successfully absorbed into____)
the proportion of a drug successfully absorbed into the systemic circulation.
What are the principles of pharmacokinetics?
(ADME)
Absorption: How will it get in?
* the way the drug moves from the site of administration & into the bloodstream.
Distribution: Where will it go?
* where the drug goes after it is in the bloodstream & where it might accumulate.
Metabolism: How’s it broken down?
* ways drugs are broken down/modified as they circulate through the body.
Elimination/Excretion: How does it leave?
* how the drug exits the body.
Drugs are metabolized by enzymes into what?
metabolites.
what is a drug metabolite?
a byproduct of the body breaking down a drug into different substance.
which organ metabolizes most drugs via enzymes?
the LIVER.
Which organ is responsible for the first-pass effect/metabolism? What is the first pass effect?
Liver.
First-pass effect: 1st pass of a drug through the liver significantly reduces the bioavailability of a drug.
basically, its like the drug losing some of its strength before it gets the chance to do its intended purpose.
Most drugs are excreted via which organ?
The kidney, via urine – which is why many drug tests are urine tests.
Related to excretion, what is the half-life of a drug?
time required for a drug to be reduced in the body by 50.
What is first order kinetics?
the amount that is eliminated is influenced by how much is in the body.
(calculations start over at half-life of drug)
EXAMPLE: if you take a single does of 16 mg, the half-life would be when 8mg (half of 16) is in the system. AFTER the half-live time duration, the remaining amount of drugs is halved again (from 8 to 4, rather than 8 again) in the same amount of time.
about what percentage of the drug remains after 4.5 half-lives?
about 5% remains.
what is zero order kinetics?
there is no half-live elimination because they are eliminated at a constant rate; like alcohol.
think of it like a leaky faucet in a bathtub. No matter how full the tub is, the leaky faucet removes water at a constant rate.
what are pros & cons of the oral ROA?
-easy & relatively safe.
-Can be slow (positive or negative). -absorption via the digestive tract is highly variable, and it will likely undergo some metabolism by the liver before getting absorbed into the bloodstream (first-pass effect).
First-pass effect: Some medications are broken down by the liver before they reach the bloodstream, reducing their effectiveness (first-pass effect).
in the mucous membranes and/or transdermal ROA, where are they absorbed?
Mucous membranes: nose, mouth, eyes, rectum, vagina.
transdermal: skin (patch, cream).
what are the pros and cons of the mucous membranes/transdermal ROA?
-Generally faster absorption than oral, very little metabolism prior to getting into the bloodstream.
-Targeted delivery.
-can sometimes damage or irritate tissues.
In the inhalation ROA, where does absorption take place?
capillaries in lungs.
