AND ANSWERS
Pharmacology - CORRECT ANSWER✅✅the study of drugs and their structure, targets of action,
mechanisms of action (MOA), distribution (how the body disburses them throughout the body), desired
physiologic effects (efficacy) and undesirable side effects (toxicity).
Pharmacokinetics includes the following: - CORRECT ANSWER✅✅ADME (absorption, distribution,
metabolism and elimination).
Pharmacokinetics is... - CORRECT ANSWER✅✅How the body effects the drug
Absorption - CORRECT ANSWER✅✅absorption from the administration site either directly or indirectly
into the blood/plasma.
Distribution - CORRECT ANSWER✅✅reversibly/irreversibly movement of drug from the bloodstream
into the interstitial and intracellular fluid.
Metabolism - CORRECT ANSWER✅✅drug biotransformation via metabolic pathways, primarily the liver,
or by other tissues.
Elimination - CORRECT ANSWER✅✅how parent drug & its metabolites are eliminated from the body
Absorption factors - CORRECT ANSWER✅✅· Gastrointestinal pH changes
· Gastric emptying
· Gastric/intestinal enzymes
· Bile acids & biliary function
· Gastrointestinal flora (type and quantity of bacteria)
· Food & nutrient interactions (most common interaction influencing GI drug absorption)
· Lipid solubility of the drug
,Distribution factors - CORRECT ANSWER✅✅· Membrane permeability: Cross membranes to site of
action
· Blood brain barrier reduces the speed of drug passage into and out of brain tissue
· Plasma protein binding: drugs bound to plasma proteins do not cross membranes (Note: Malnutrition =
âalbumin = á free drug = greater pharmacologic response)
· Aging cause a reduction in production of plasma proteins
· Lipophilicity of drug: lipophilic drugs concentrate in adipose tissue; remain in the body for a longer
period of time
Volume of distribution - CORRECT ANSWER✅✅· Body Composition
- Increased Total body water and extracellular fluid
-Decreased Adipose tissue and skeletal muscle
· Protein Binding (changes with aging)
-Albumin, bilirubin, a1-acid glycoprotein
-Albumin affected by nutrition
-Low albumin (hypoalbuminemia) can cause less protein-bound drug reaching the tissue site of action.
· Tissue Binding
- Compositional changes
Metabolism factors - CORRECT ANSWER✅✅o Drugs can undergo metabolism in the lungs, blood, liver,
intestines and kidney
o Volatile drugs are primarily excreted by the lungs
· The body changes drugs to more or less active forms (metabolites), increases water solubility to
increase elimination.
Phase 1 Metabolism - CORRECT ANSWER✅✅· Cytochrome P450 system
· Located within the endoplasmic reticulum of hepatocytes.
· Through electron transport chain, a drug bound to the CYP450 system undergoes oxidation or
reduction.
· Drug metabolism in the liver is also affected by:
-Enzyme induction
,- Drug interactions
CYP450 - CORRECT ANSWER✅✅· CYP: a set of isozymes primarily found in the liver and GI tract
· Convert lipophilic drugs into more polar (and soluble) molecules
· Considerable genetic variability exists across race and gender
· Results in CYP450 polymorphisms which have a direct effect on drug metabolism.
Four isozymes are responsible for the majority of Phase I Metabolism reactions - CORRECT
ANSWER✅✅1. CYP3A4/5
2. CYP2D6
3. CYP2C8/9
4. CYP1A2
If you have a patient experiencing a pharmacokinetic drug interaction, consider...... - CORRECT
ANSWER✅✅CYP450.
· Some drugs or exogenous substances can induce CYP isozymes (less effect). Example.... - CORRECT
ANSWER✅✅St. John's wort (CYP3A4) and hormonal birth control
CYP450-related drug interactions can make predicting blood plasma levels/steady state levels difficult.
Example.... - CORRECT ANSWER✅✅If a drug inhibits enzymatic activity, a substrate drug for that
enzyme system will have a greater concentration in the blood.
If a drug inhibits CYP isozymes, what is the effect of the substrate drug - CORRECT ANSWER✅✅The
substrate drug will have greater effect
Phase 2 Metabolism - CORRECT ANSWER✅✅· Polar group is conjugated to the drug
· Results in increased polarity of the drug
Types of phase 2 metabolism reactions - CORRECT ANSWER✅✅- Glycine conjugation
, -Glucuronide conjugation
-Sulfate conjugation
What is competitive antagonism? - CORRECT ANSWER✅✅where one drug displaces another on cell
receptors.
How is metabolism effected by different ethnic groups? - CORRECT ANSWER✅✅Different ethnic groups
may have different hepatic metabolism rates
Routes of elimination - CORRECT ANSWER✅✅1. Pulmonary = expired in the air (volatile substances)
2. Bile = excreted in feces
3. Renal
-glomerular filtration
- tubular reabsorption
- tubular secretion
Glomerular filtration rate (GFR) (Normal) - CORRECT ANSWER✅✅90-125L/min
Most elimination involves..... - CORRECT ANSWER✅✅renal function. (Renal blood flow, creatinine
clearance (CrCl) )
Linear drug elimination - CORRECT ANSWER✅✅Rate of elimination is proportional to amount of drug
present
volatile drugs are excreted by the.... - CORRECT ANSWER✅✅lungs
Bioavailability - CORRECT ANSWER✅✅A measure of the extent of drug absorption for a given drug and
route (from 0% to 100%).