Pharmacolonetics Flashcards
Describe the process of oharmicolinetics
Drug is anaorbed and delivered
It is then distributed and is diluted
The body will begin to break down and excrete the drug
Must be administered repeatedly
Define pharmacokinetics
The complex sequence of events that occur after a drug administers to a body
Define absorption
The movement of a drug from the site of administration to the systemic corculation.
Define ionized
Charged and hydrophilic
Define non ionized
Uncharged and lipopholic
What do hydrophilic drugs do
Dissolve in water (tissue, fluid, lymph)
What do lipophiloc drugs do
Dissolve in oil based fluids and absorbed well across phospholipid cell membranes
What can determine the degree to which a drug becomes ionized and absorbed?
Oh
What way are lipophilic drug best administers?
Orally
Weakly acidic drugs will not ionize in what type of environment?
Acidic
Weakly basic drugs will not ionize in what kind of environment?
Alkaline
What happens if a drug is introduced to an environment where it readily ionized?
Will not absorb
What form do drugs need to be in to penetrate the GI mucosa?
Oral
What can alter or delay absorption rate?
Enteric coatings or sustained release compounds
What form do parent real drugs need to be in?
Hydrophilic form
Decreased gI motility will do what to a drug?
Lengthen absorption time
Increased GI motility will do what to a drug?
Shorten the time the drug is in the GI tract which may not allow dissolution
What an the presence of food do to a drug?
May interfere with dissolution and absorption
What is the first pass effect
Detoxification by the liver
What do all drugs need to survive before entering the systemic system?
The first pass effect/liver
How can blood flow be altered to interfere with absorption rate?
Adrenaline can increase blood flow to the muscles and decrease blood flow to the intestines
How can temperature effect blood flow?
Can cause Vado constriction or dialation
Describe drug distribution
Physiological movement of drugs from the systemic circulation to the tissues
What are three ways drug movement can occur
Passive diffusion, facilitated, active transport
What is passive diffusion
Movement of drug molecules from area of high concentration to low
What is facilitated diffusion?
Diffusion that needs a special carrier molecule but does not require energy
What is active transport
Requires carrier molecule and energy moving from low to high
Define phagocytosis
Molecules are physically taken in or engulfed
Define pin oxytocin
Cell drinking, engulfs liquid particles
Why is pinocytosis and phagocytosis important?
Helps transfer large molecules that are to big to fit through cell membrane
What Are seven factors that can affect drug distribution
Membrane permeability, blood brain barrier, placenta, tissue perfusion, protien binding, volume of distribution? Disease
What are two ways membrane permeability can affect drug distribution?
Molecule size vs membrane pores/fenistration
How can the blood brain barrier effect drug distribution?
Fever and inflammation can alter barrier allowing drugs to get in
How can the placenta effect drug distribution
Protects most drugs from the fetus
How can tissue perfusion effect drug distribution
The blood supply to an area can determine how rapidly drugs will be distributed
How can protien bonding effect drug distribution
Some drugs bind to the protiens which can sometimes be to big to leave the blood stream
How can volume of distribution effect drug distribution?
How well a drug is distributed throughout the body is based on the concentration of the drug in the blood
The larger the volume of distribution…
The lower the drug concentration
What are three ways a disease can effect drug distribution?
Antibiotics can’t diffuse well into abscesses or exudate a
Heart failure or shock decreases blood flow
Liver failure can cause a decrease in the amount of protien for binding
Define drug metabolism
Chemical alteration of drug molecules by the body cells to a metabolite that is in an activated, inactivated, and/or toxic form
Define bio transformation
A bodies ability to change a drug chemically from a form in which it was administered to a form that can be eliminated from the body
Where does most buoy transformation take place?
In the liver
Where does other biotransformation take place? 3
Kidneys, lungs, nervous system
What is metabolite 1
Usually inactive but can be more active
What is metabolite 2
Usually more hydrophilic and more ionized so it is less likely to get stored in fat
What are four chemical reactions of drug biotransformation
Oxidation, reduction, hydrolysis, conjugation
What is oxidation
Loss of electrons
What is reduction
Gain of electrons
What is hydrolysis
Splitting of drug molecules and adding water molecules to each part
What is conjugation
Addition of glucuronic acid to the drug molecules making it more water soluble
What are five ways animal factors affect drug metabolism
Species, age, nutritional status, tissue storage, health status
Why do cats have a limited ability to metabolite aspirin, narcotics, and barbiturates?
Reduced ability to form glucuronic acid
How can drug metabolism be different in young and old animals?
The liver enzyme systems are not fully developed in young and deteriorated in old
How can nutritional status effect drug metabolism?
Decreases protien=decreased metabolism
How can health status effect drug distribution?
Liver disease=decreased protiens
What are three ways the kidneys eliminate drugs?
Glomerular filteration, tubular secretion, tubular reabsorption
How does glomerular filteration work?
Nephron pushes water and and small molecules through glomerular capillaries into the iron
What will increased blood pressure do in glomerular filteration?
Increase the filtration rate
What will be filtered through the glomerular filteration?
Small mom ionized and non protien bound
What is tubular secretion?
Active transport across the convoluted tubule moving molecules from blood to urine
WHat is tubular reabsorption?
Loop of henle of nephron, lipid soluble, non ionized will be reabsorbed into the blood syream
How does the liver excrete drugs? 4
Passive diffusion from blood to hepatic urea to bile to duodenum
How are drugs eliminated by milk?
Some drugs are passed from blood stream to mammary glands
How do lungs excrete drugs?
Has molecules move out of the blood and into alveoli and are exhaled
What are three cellular drug effects?
Secretion of a substance, contraction of muscle cells, cell death
What are three examples of monte rotor mediate drug/effects
Mannitol EDTA and antacids
What nonreceptor mediated drug draws water into renal tubules?
Mannitol
What nonreceptor drug combines with Ca to prevent clotting?
EDTA
What nonreceptor drug makes Ca, mg, and al combine with HCL?
Antacids
