Intro to Pharm pt 2

Pharmacokinetics

What is how medication moves through the body

pharmacodynamics

what is what drugs do to the body and guide safe drug administration and evaluation of effectiveness

order

Dose administered

drug in systemic circulation

drug at site of action

drug interaction with receptor

RESPONSE

pharmacokinetics

What is the actual concentration that a drug reaches in the body results from a dynamic equilibrium involving the rates of several processes

Absorption

in pharmacokinetics, this is what happens to drugs from point of entry until reaching the circulating fluids and tissues

absorption

What goal is to maximize therapeutic effects and minimize adverse effects

passive

In absorption, moving area of high concentration to low

active

In absorption, requiring energy (ATP), moving from low to high concentration

parenteral/ intravenous

This administration is the most rapid onset and fully absorbed as the drug directly enters the blood stream

intramuscular

This administration is faster than subcutaneous due to increased vascular supply associated with muscular tissue; while subcutaneous enters fatty tissue right under the skin

Oral

This absorption is the slowest with the first barrier being the acidic environment of the stomach

-most COMMON

-least INVASIVE, cheapest

-Easiest route from home administration

Distribution

What is the movement of drug from bloodstream to tissue

factors in distribution

What affects

-perfusion of reactive tissue

-lipid solubility and blood brain barrier

-plasma protein binding

-placental barrier

perfusion of reactive tissue

What will affect distribution due to

-decreased blood flow due to dehydration

-blocked vessels due to atherosclerosis

-constricted vessels due to uncontrolled hypertension

-weakened pumping by the heart muscle due to HF

blood brain barrier

What is when only certain medications made of lipids or have a carrier can get through

plasma protein binding

What is when a percentage of the drug gets bound to PP when entering the bloodstream. The protein bound drug is inactive but the portion of the drug that escapes free to bind to the target tissue and exert or block an action

placental barrier

It is always important to consider the effects of medication during pregnancy or for patients who may become pregnant.

It is permeable to some medications, while others have not been specifically studied in pregnant patients

Some drugs can cause harm to unborn fetus during any trimester

metabolism/biotransformation

What are chemical reactions that the body uses to convert drugs into nontoxic substances

detoxify foreign substances

Enzymes in the liver, GI tract lining, and circulating throughout the body help to do what? So this process makes medication less active, and more easily excreted

First Pass Phenomenon

This happens for oral dosing of medications. There is a potential for large percentage of oral dose to be destroyed int he liver without reaching the targeted tissues

***only happens orally**

**it will pass in liver, so there will be breakdown in the liver making it less active

Elimination

what is removal of drug from body, the kidneys play the most important role

glomerular filtration

Some drugs are water soluble by the liver and are easily excreted by what?

actively

How are some drugs transported across the glomerular membrane for filtration through the kidneys?

acid or bicarb

What is exchanged through active transport across the glomerular membrane for filtration and the acidity of urine will often affect the exchange

Critical Concentration

What is the amount of drug needed to cause a therapeutic effect and requires the dynamic equilibrium of pharmacokinetics

onset

what is the time it will take for the therapeutic effect to begin

loading dose

what is when quick effect is needed, it is higher than normal dose is used to reach critical concentration sooner

Peak

In pharmacokinetics:

-HIGHEST concentration of medication in someone

-Timing of medication depends on route

therapeutic index

What is the ratio of toxic to therapeutic levels

Trough

In pharmacokinetics:

-LOWEST concentration of medication in an individual

-This is measured immediately BEFORE the next dose