Basic Pharm principles III (exam 2) Flashcards
several factors contribute to the effects of drugs… list some of them
-molecular structure
-characteristic of drug
-concentration of drug at site of action (target site)
the above includes: Dose, route of administration, Time since administration, frequency of administration, sex, genotype
-History of administration
-set
-setting
Pharmacokinetics focuses on ADME…what is that?
Absorption Distribution Binding at a target site Metabolism Excretion
Pharmacokinetics helps to optimize drug therapy by determining :
dose
dosage form
dose regimen
What are the enteral routes of drug admission into the body? (3)
Mouth
Rectal
Sublingual (buccal)
What are the parenteral routes of drug admission into the body (10)
intravenous (IV) intramuscular (IM) subcutaneous (SC, Sub Q) intraarterial intrathecal Intracerebroventricular (ICV) transdermal inhalation topical mucous membranes
What are the most common routes of admission? (5)
Mouth intravenous intramuscular subcutaneous topical
There are three general mechanisms by which substances (besides water) cross cell membranes. What are they?
- diffusion
- facilitated diffusion
- active transport
diffusion and facilitated diffusion are both example of ___________ transport
passive
What is bioavailability?
the fraction of dose that actually enters the systematic circulation
bioavailability is based off of absorption factors. Name them (6)
- Dose
- Dose form
- Route of Administration
- Dissolution Rate
- Circulation
- Drug factors (lipid solubility, water solubility, pH)
True or False: Once absorbed into the circulatory system, the drug is distributed throughout the body
true
True or False: A large amount of the drug is in contact with receptors at any given time
false: very little amount of the drug is in contact with receptors at any given time
List 5 factors that effect the accumulation of drug in tissue
- lipophilocity of drug
- perfusion of target
- sex
- Concentration gradient
- Blood brain barrier
Men have proportionally (more/less) fat tissue than woman
less
Woman have proportionally (more/less) water than men
less
does drug action differ over sex?
yes!
What is the general purpose of circumventricular organs?
- communicating with CSF
- communicating between the brain and periphery via the blood
(look at this slide for more information)
What is biotransformation?
the chemical alteration of drug in the body
what is catabolism vs anabolism
catabolism is the breakdown of molecules and anabolism is the combining of molecules
in drug metabolism, (catabolism/anabolism) is inferred?
catabolism
*generally a gradual conversion to a more hydrophilic (POLAR, less lipophilic) form so that it is excreted
List the 5 Drug Metabolism outcomes
- ) Conversion of Active molecule into inactive molecule
- ) Conversion of inactive molecule to active molecule
- ) Conversion of a Toxic molecule into a non-toxic molecule
- ) Conversion of a non-toxic molecule into a toxic molecule
- ) Conversion of lipid soluble form into water soluble form (for excretion)
What is cleavage?
the metabolic process of splitting into smaller molecules
What is oxidation?
the metabolic process of combining with oxygen and increase of electropositive charge by net loss of electrons
What is reduction?
decrease of electropositive charge by net gain of electrons
What is conjunction?
the metabolic process of combing with endogenous compound
What organ does the most of the drug metaboling?
liver
oral medications travel via the ____________ to the ______ before they enter the general _________
bloodstream
liver
blood supply
what does “first pass” refer to?
the metabolism that occurs between absorption and systemic circulation
For drugs administered to the GI tract, the first pass effect (by the liver) occurs because…….
the drugs pass through liver prior to entering the general (systematic) blood supply
What percent of oral dose enters the stomach?
what percent enters hepatic portal vein?
what percent of the original dose is left after the first visit to the liver?
100%
70%
15%
What are the fluid ways that drugs can be excreted out of the body?
Sweat Tears Saliva Mucous urine bile human milk
Look at drug excretion slide
What is Zero-Order?
Elimination of a constant quantity of drug per unit time
A reaction is zero if……
talk about the graph
concentration data are plotted versus time and the result is a straight line
Half life (increases/decreases) with (increasing/decreasing) concentration
decrease for both
What is First-Order?
elimination of a constant fraction of drug per unit time
Do most drugs have a Zero-Order or First-Order?
First-Order (~95%)
in First-Order the rate of elimination is proportional to______________________________
the concentration of the drug
Compare the half-life of zero vs first order
zero- half life decreases with decreasing concentration
first- half life is constant (ie: 50% every 4 hours) regardless of the drug concentration
A reaction is first if……
talk about the graph
concentration data are plotted versus time and the result is an exponential decrease
in general, the effects of drugs on a fetus/neonate is (better/worse) than in adults
worse
Why are these effects better/worse?
- have an immature BBB
- fewer plasma proteins (to bind to drugs and keep them from entering the brain)
- greater proportion of blood flow to the brain
- (far) fewer liver enzymes
- slower drug excretion
