Pharmacokinetics Flashcards
What is Pharmacokinetics?
- what the body does to the drug
What is Pharmacodynamics?
- what drug does to the body
What is the Process that Pharmacokinetics occurs?
- ADME
What is Absorption?
- The way drugs are absorbed
- IV = NO absorptiong [already in blood]
- NON-IV = needs absorption
What is the way that a drug is Absorbed
- Passes through stomach into small intestine [where it occurs the most]
- after gut goes to the hepatic portal vein and into liver [1st pass metabolism]
- Back through bile duct to the gut where it is reaborbed [entero hepatic recycling]
What are the two processes of absorption?
- Passive: High to low conc [i.e blood]
- Active: transport proteins move the drug
What is Disintegration within absorption?
- drug gets broken down in the GI tract into smaller piece
What is dissolution within absorption/
- those smaller piece [from disintergration] are dissolved into the active form
What is the rate of absorption based on the doseages forms? [fastest to slowest]
- IV –> SL –> ODT –> Immediate Release –> Extended Release
How are drugs made to increase the absorption rate?
- increase dissolution by reducing particle size = increase surface area
- This is called micronized
What is solubilty within absorption?
- the rate and extent the active drug [after dissolution] is absorbed
What is Bioavailability?
- extent of the drug absorption into the systemic circulation
How is Bioavailability reported?
- the % [0 to 100] of the drug absorbed from oral vs iv
what does it mean to have a high or low Bioavailability?
- HIGH: good absorption [> 70%]
- LOW: bad absorption [< 10%]
What is distribution?
- How the drug move from the systemic circulation to the tissues and organs
What are some of the factors that favor distribution?
- High Lipophilicity
- Low moleculer weight
- unionized status
- low portein binding
What is the equation for the corrected calcium?
- Ca(reported) + [(4.0 - Albumin) x (0.8)]
What is metabolism?
- drug is converted from its orginial from to another form to get ready for elimination
What is Excretion
- irreverible removal of drugs from the body
What is clearence?
- the rate of the drug being remove in a certain plasma volume over a certain time period
- the efficacy of drug removal from the body
What is the equation for clearence?
- Cl = [(Rate of elimination)/(Drug conc.)]
What is the difference between first-order & zero-order elimination
- 1st: precentage eliminated is the same
- 0: the amount eliminated is the same
What are the three drugs that exhibit michaelis-mentin kinetics
- Phenytoin, Theophyille, Voriconazole
What is important to know about the Michaekus-Mentin Constant
- Km is when conc. is half the rate
- Less than Km = 1st
- More than Km= 0
What is the rate elimination constant
- fraction of the drug that is elminated per unit of time
What is the elimination rate constant equation
- Ke = [(Cl)/(Vd)]
