Exam 1 Flashcards
Basic Principles of Pharmacology; Receptors
Agonist
Binds to Receptor & elicits response (Activator)
Antagonist
Binds to Receptor & blocks response (Inhibitor)
Pharmacodynamics
What the drug does to the body
Pharmacokinetics
What the body does to the drug
Pharmacogenomics
Genetic profile / how an individual responds to a drug
Chirality (stereoisomerism)
“Mirror Images” optical isomers
Orthosteric
Binds to active site
Allosteric
Binds outside of active site
EC 50
Concentration of drug where 50% of drug has taken affect
Kd
Drug concentration where 50% of receptors are bound
Toxicology
Study of undesirable effects of chemicals on living systems
Native ligand
Produced by body to bind to receptor to elicit response
Materia Medica
First medical textbook of pharmacology
Covalent bonds
Very strong & in many cases not reversible. Share electron bonds
Electrostatic
Charged molecules.
Weaker than covalent.
Hydrophobic
Lipid Soluble Drugs
Weakest / most numerous
Noncharged, MUST fit perfectly in receptor to elicit response.
“Phobia” to water
Poisons
drugs that have almost exclusively harmful effects.
Biologic & Nonbiologic
Toxins
Poisons of biologic origin
Constitutive Activity
Active even in absence of agonist activity
Racemic Mixture
50:50 mixture of two enantiomers, chiral molecules (mirror images)
Receptor
Target molecule that plays a regulatory role in the biologic system (Large Protein)
Receptor site
Active site on receptor to which ligand/drug binds to
B max
Point where maximum amount of receptors are bound to
E max
Point where maximum effect is seen
Competitive Inhibitor
Compete with agonist for active site binding, can be surmountable (surplus of agonist) or insurmountable (covalent bond forms)
Allosteric Inhibitor
Do not compete with agonist, binds outside of active site, can have inhibitor effects to which the agonist can not over come (Insurmountable)
Inverse Agonist
Greater affinity for Ri (Inactive form of receptor), Becomes less receptive, essentially an antagonist
Partial Agonist
Produce a reduced response at full receptor occupancy
In presence of full agonist, acts as antagonist
In absence of full agonist, acts as agonist
Potency
The concentration of drug required to produce 50% of drugs maximal effect (EC50)
Physiological Antagonism
A drug that counters the effects of another by binding to a different receptor and causes an opposite affect
Efficacy
The maximum effect a drug can produce regardless of dose (Emax)
Stereoisomers
Molecules that have the same molecular formula and differ only in how their atoms are arranged
Endogenous
Produced within the body
Exogenous
Produced outside the body
Imhotep
First recorded physician
Hippocrates
Fathers of Western Medicine
Caduceus
Symbol of peace and commerce (mistaken for rod of Asclepius) Winged staff intertwined with Two serpents
Asclepius
God of medicine staff intertwined by one serpent
Paracelsus
Father of Toxicology “The dose makes the poison”
Controlled drug trial
Compares drug to placebo to monitor for actual effects
Molecular Weight of most drugs
100-1000 Daltons
ADME
Absorption, Distribution, Metabolism, Excretion
Low Kd
High drug/receptor affinity
High Kd
Low drug/receptor affinity
Agonist “mimic” or Indirect agonist
Works inside the cell to inhibit the molecules responsible for terminating the action of an agonist
A drug must have the proper ___ to interact with a receptor
Shape, Size, Electrical Charge, or Atomic Composition
Van der Waals forces
Weak electrostatic forces that attract neutral molecules
Bond strength and specificity have an __ relationship
Inverse
What is nonspecific binding
when a drug binds somewhere else
Ex. albumin
What makes a compound organic?
Having Carbohydrates, Lipids, Proteins
Desensitization
cell shuts down signaling process; “protective mechanism”
Good Receptor Properties
selective - bind only to certain receptors
alteration - binds to ligand & causes change
Bound (albumin) drugs
can not cross barriers
Unbound Free form Drugs
can cross barriers
Bad Receptor Properties
- binds but cause no change (drug carriers)
- not specific
Albumin mostly bind to
Acidic drugs
Displacement of drugs is
when two drugs compete to bind to albumin (more free form drug)
Albumin has how many binding sites?
2
Maximal Efficacy
maximal effect; might see side effects at this point
Clinical effectiveness of a drug depends on
maximal efficacy
Therapeutic Index is
The distance between ED50 & TD50; Established safety margins
TD50 is
median toxic dose; point where 50% of toxic affects seen
ED50 is
Median effective dose; point where 50% of dose sees desired effects
Narrow Therapeutic Index
dangerous; closely monitored (ex. digoxin)
Wide Therapeutic Index
relatively safe; larger margin for error; OTC meds (acetaminophen)
Variations in drug responsiveness
Tolerance; Tachyphylaxis (quick tolerance); Chemical agonist (drug); Physiologic antagonism (body blocks or heightens response)
Four causes of drug responsiveness variations
- Alteration in concentration of drug that reaches receptor;
- Variation in concentration of endogenous receptor or ligand;
- Alteration in number of functioning receptors;
- Changes in downstream effect post-receptor
In order to cross barriers
drugs need to be uncharged
Most drugs are ___ or ___
“weak acids” or “weak bases”
pKa relates to what?
pH
If pH < pKa it
favors protonated form (H+ attached)
If pH > pKa it
favors unprotonated form (no H+)
Acids tend to ___ __ into solution
release H+
Bases tend to ___ __ from solution
absorb H+
Acids are ___ when protonated (H+ attached)
uncharged
Acids are __ when unprotonated (No H+)
charged
Bases are __ when protonated (H+)
charged
Bases are __ when unprotonated (No H+)
uncharged
“Weak acids” in acidic environment
protonated/uncharged
“Weak acids” in basic environment
unprotonated/charged
An example of a weak acid?
Aspirin
“Weak bases” in acidic environment
protonated/charged
“Weak bases” in basic environment
unprotonated/uncharged
An example of a weak base?
Morphine
Monoclonal Antibodies are created by
biologic organisms; clones of a single parent cell
monoclonal antibody suffix
- mab
Benefit of monoclonal antibodies?
specificity - bind to a specific site, can target certain protein; can cause apoptosis (cell death - cancer cells)
The variable region
region that binds to specific protein
The constant region
region that does not change (mediates immune response after binding)
4 ways a drug action ceases
- Drugs stops binding to receptor
- Downstream effectors go away/run out
- Receptor degradation (covalent bond)
- Desensitization
Malnourished patients and dosing
Require lower dose of medication; less albumin available = more free/unbound drugs
a1 glycoproteins mostly bind to
basic drugs
Lipoproteins most bind to
neutral drugs
Therapeutic Index can be determined by which equation
TI = TD50/ED50 (human)
TI = LD50/ED50 (animal studies)
Unusual/unsuspected response to a drug is termed
idiosyncratic (don’t know why it happened)
Idiosyncratic responses are often attributed to
genetic factors
The largest and most important cause in drug response variation is
changes in components of response (downstream effectors)
pKa
dissociation constant
Endogenous antibodies have 2 major functions
- recognize and bind to antigen
- Induce immune response after binding
Monoclonal antibodies do not
elicit immune response
Spleen cells fused with myeloma cells are
Immortal; cloned; utilized in monoclonal antibody production
Food and Drug Administration (FDA)
federal agency responsible for regulating food and drug products
For drugs to be approved by FDA they must be proven to be
“Safe & Effective”
FDA regulates the way drugs can be
marketed (what claims can be made by drug/product)
FDA famously denied approval for ___ in the 1950s
Thalidomide - teratogenic medication; utilized for morning sickness in Europe
In Vitro studies are looking for new drugs identified as
Lead compounds
Prior to conducting human studies drugs researchers must first
Ensure safety in animals & be approved for IND (Investigational New Drug)
Phase 1 clinical trials
Testing a new drug on small drug of healthy individuals to find out how the body reacts to the drug
Phase 2 clinical trials
Drug is tested on target population to determine if is more beneficial than placebo (double blind)
Phase 3 clinical trials
Drug is tested on large target population (second double study)
Prior to phase 4 drug studies a __ is required
NDA (New Drug Application)
Phase 4 clinical trials
Approved and gone into market; after 20 years patent expires and generic meds can be made
Receptor
component that interacts with drug/ligand and initiates chain of events
Receptors are
Proteins
Orphan receptors
receptors whose natural ligands are unknown
G-protein coupled receptors (GPCRs)
a signal receptor protein in the plasma membrane that responds to the binding of a signal molecule by activating a G-protein
Ligand-gated ion channel
act as “gate”; open channel when something binds to them
Ion channels
open because of change in charge on membrane
Signaling molecule
drug or endogenous ligand that binds to receptor of GPCR
Second messenger
molecule that is activated byeffector proteins
Effector proteins
have an effect on the behavior of a cell
Most common second messenger
cyclic AMP (cAMP)
Lag period
delay in gene expression related to the requirement for transcription/translation
Drugs with a greater persistence require ___ dosing
less frequent (they last longer)
Conformational change
The receptor binds to a drug & changes in some form
Dose response is related to
number of receptors bound (linear) or strength of signal transduction cascade (multiple responses)
Kinase
any enzyme that attaches a phosphate group to another protein
a phosphorylated protein is
active
Steps in Phosphorylation Cascade
- Drug bind to receptor
- Drug invokes conformational change
- Protein Kinase is activated
- Chain reaction of protein phosphorylation (phosphate attahed)
- Effector is reached & activated
To activate intracellular receptor drug must be
Lipid soluble or uncharged (must cross cell membrane)
A Catalytic receptor
activates an enzyme
2/3 of all non-antibiotic drugs are activated by
GPCRs
G-Protein trimeric (3 subunits); the alpha subunit is
the most important; it initiates a response of an effector protein
When inactive, the alpha subunit of the G-protein is bound to
GDP (guanine diphosphate)
When active, the alpha subunit of G-protein is bound to
GTP (Guanine triphosphate)
G-protein
A GTP binding protein that relays signal from plasma membrane signal receptor (G protein coupled receptor), to signal other transduction proteins inside the cell
GPCRs structure:
seven transmembrane a-helices
GPCRs are a
seven transmembrane spanning receptor region
Desensitization is
utilized when covalent bonds form on receptor by drug/ligand to stop constant signaling
What are the two possible outcomes that may occur with desensitization
- The covalent bond breaks between drug & receptor to which receptor is recycled
- The covalent bond does not break and a lysosome breaks down receptor
What is beta arrestin?
it is a protein that binds to OH groups on receptors to stop them from signaling
What is a clathrin pit?
a protein involved in endocytosis (engulfs receptor with beta-arrestin attached and brings it into cell)
Phosphatase
strips phosphate group from protein
With RTKs you have _____ that join to form a ___
two monomers; dimer
How many ATPs are utilized during phosphorylation of RTKs
6
Receptor Tyrosine Kinase ligands typically are
Growth factors or Adhesion factors
Ligand binding stimulates what on RTKs
Dimerization & Phosphorylation of tyrosine (makes it act like a kinase)
Four types of Catalytic Cell Surface Receptors
- Tyrosine Kinase
- Tyrosine Phosphatase
- Serine/Threonine Kinase
- Guanylate Cyclase
Steps in the RTK process
- Two RTK are bound by ligands (requires 2)
- Both monomers join to form Dimer
- The dimer becomes phosphorylated utilizing 6 ATPs
- The receptor begins to interact with effector protein
Ion channels
pores that allow charged molecules to go from one side of membrane to the other
Ion channels can be opened by
A ligand or voltage
Voltage gated channels are found in
Excitable cells (Neuron, muscles, endocrine cells)
Membrane potential is called
Threshold
Inotropic-gated Ion channel
Ligand binds to it & opens channel on same protein
Describe GPCR activating Ion channel
- Ligand binds to GPCR
- G protein is activated
- G protein activates effector protein
- Effector protein produces 2nd messenger
- 2nd messenger binds to ion channel & Ion channel opens
Ligands that bind to receptors inside the cell
- Gases (nitric-oxide)
- Lipid soluble (steroid hormone)
Metabotropic-gated Ion channel
Ligand activates GPCR & second messenger activity opens channel
Four ways a drug can cross a membrane
- aqueous diffusion
- lipid diffusion
- special carriers
- Endocytosis & exocytosis
water channels are
Aquaporin channels; pores that allow water into cell
Aquaporin channels allow drugs into cell if they are ___ ___ by process of ___
water soluble; simple diffusion (high concentration to low)
Aqueous diffusion will not be allowed if drug is
Highly charged or Bound to large proteins (carriers)
Lipid Diffusion allows ___ ___ drugs to cross membrane
lipid soluble
Special carriers
Bind to drug & move it across barriers (by active transport or facilitated diffusion)
Endocytosis
membrane engulfment
Exocytosis
releasement out of membrane
Volume distribution (Vd)
relates amount of drug in body to concentration in blood (how much we gave vs. how much is in the blood)
Clearance is
ability of body to eliminate drug; given in percentage of how much drug is eliminated/hr
Elimination does not equal
clearance
Elimination changes based on
clearance (in first order)
The higher the volume distribution
the less amount there is in the blood
Equation for volume distribution (Vd)
dose/drug concentration = Vd
ex. (10mg/Kg / 125mg/L = 0.08L/kg)
Target concentration can be calculated from
volume distribution
Clearance predicts
the rate of elimination in relation to drug concentration
Equation for clearance
CL = rate of elimination/C
Clearance for almost every drug will remain
constant
Equation for Rate of Elimination
ROE = CL x C
First order elimination is
Clearance is constant; rate of elimination varies with concentration
Zero order elimination is
Rate of elimination is constant; clearance varies with concentration (so much drug in body, elimination mechanism saturated)
Ex. Ethanol, phenytoin, ASA
Vmax
Maximum rate you can eliminate drug
Three main drugs Zero order applies to
Ethanol; Phenytoin; Aspirin
Sodium channels are considered to be
Fast
Calcium channels are considered to be
Slow
Four stages of gated channels
- Channel closed; internal gate 1st closed & 2nd (innermost) gate open
- Channel activated & both gates open
- Channel is inactivated; 2nd gate closes to prevent too many ions; 1st gate remains open
- Channel is deactivated & both gates closed
Rational Dosing
goal is to achieve desired beneficial effect with minimal adverse effects
Whole blood constant is
0.08 L/Kg
Plasma volume constant is
0.04 L/Kg
How many nanograms in a mg
1,000,000
How to calculate dose given Vd
Vd x Target conc. = dose
To get dose, divide ___ by ___
Target concentration; percent in blood
Rate of elimination is
Mass of drug eliminated per unit time. (mg/hr)
What is half life (T 1/2)?
Time it takes for the body to get rid of half the concentration of drug
What is the formula for half life?
T 1/2 = (0.7 x Vd)/CL
High extraction drugs are
Drugs that are eliminated in large portions during “first pass effect”
Extraction ratio categories & percentages
- High extraction ratio > 70%
- Intermediate extraction ratio 30-70%
- Low extraction ratio < 30%
The only time we have a high clearance is when we have both
A high extraction ratio & high (normal) blood flow
How many half lives does it take to reach steady state (No bolus)?
4 half lives
How many half lives does it take to eliminate the drug from the body when the dose is stopped?
4 half lives
If dosing interval is shorter than four half lives __ will develop
Accumulation (toxic levels can be reached)
What is Bioavailability?
Fraction of unchanged drug reaching systemic circulation
Giving a drug IV will make the bioavailability
100%
Factors that affect bioavailability (6)
- Physical properties (pKa, Hydrophilicity, solubility)
- Formulation/route
- GI - diet, gastric emptying
- Overall heath/disease state
- Interactions with other drugs
- Circadian
Absorption does not equal concentration because
once absorbed in gut medication must undergo “First pass effect” in liver
Routes that bypass First Pass Effect
- IV, IM, SC
- Inhalation (has own metabolism/first pass effect)
- Sublingual or transdermal
- Rectal suppositories
Target concentration
concentration that will produce desired effect without adverse effects
Target concentration is ____
Therapeutically determined (what is the end goal?)
Ex. Digoxin
- 2ng/mL: controls a fib
- 1ng/mL: manages HF
Formula for Dosing rate
Dosing rate = CL x TC
Formula for Dosing rate with less than 100% Bioavailability
Dosing rate = (CL x TC) / Foral (bioavailability)
Maintenance dose formula
Dosing rate/ Foral (bioavailability) x Dosing interval
Why is a loading dose given?
To reach steady state quickly
Formula for Loading dose?
LD= Vd x TC
A loading dose must be given
Slowly, needs time to distribute
The most important factor in Therapeutic drug monitoring is?
Clearance
Drugs that do not penetrate fat (stay in bloodstream) utilize ___ when drug dosing
Ideal Body Weight (IBW)
Creatine clearance give us
overall idea of health/function of kidneys
Where does Biotransformation primarily occur?
Liver
What is Biotransformation?
changing or bio modifying a drug to make it more or less active
First pass effect is
passing through the liver prior to reaching systemic circulation
Oral Hepatic portal system of drug
GI –> Local veins –> Hepatic portal Vein –> Sinusoids (Leaky capillaries) –> Hepatic vein –> Vena Cava –> Systemic circulation
Biotransformation takes place in liver by which cells?
Hepatocytes
Where is a drug bio-transformed?
Sinusoids
Hepatic Artery route (all IV drugs take)
Systemic circulation –> Hepatic artery –> Sinusoids –> Hepatic Vein –> Vena Cava –> Systemic circulation
Phase 1 Reactions
utilization of an enzyme to add or unmask a functional group (convert drug to more polar metabolite)
Phase 1 reaction types:
- Oxidation (most important) (Lose electrons)
- Reduction (Gain electrons)
- Dehydrogenation (Remove OH group)
- Hydrolysis (add OH group)
Most drugs are modified by which oxidation reaction in phase 1
Cytochrome P450
Cytochrome P450 enzymes have
- low substrate specificity (Bind to multiple drugs)
- Multiple different types (CYP-***)
- Mixed-function oxidases (oxidizes & makes drug hydrophilic)
CYP3A4
cytochrome P450 subtype that metabolisms 50% of drugs undergoing phase 1 reactions
The Cytochrome P450 that occurs most often in blood types is (wild type)
CYP3A4*1
P450 Induction
Enhance synthesis or inhibit degradation (increased levels of P450)
P450 Inhibition
Decrease or irreversibly inhibit P450
Competitive inhibition is
co-administration of drugs metabolized by same P450 (cant metabolize 2 drugs at once)
The effects of inhibition or induction of CYP450 depend on
if metabolism by P450 activates or deactivates the drug
Three CYP subtypes & percentages of phase 1 reactions they are involved in
- CYP2B6 (8%)
- CYP2D6 (20%)
- CYP3A4 (50%)
Phase 2 reactions
Conjugation reactions - attaches a molecule making it larger & more hydrophilic (less likely to cross barrier)
Types of phase 2 conjugations (7):
- Glucuronidation
- Acetylation
- Glutathione conjugation
- Glycine conjugation
- Sulfation
- Methylation
- Water conjugation
Glucuronidation
- uridine diphosphate glucuronosyltransferases (UGTs) enzyme - carrier molecules - add glucuronic acid making it easily excreted in urine
Glutathione-S-Transferase (GST) enzymes attach
- Glutathione to xenobiotic (foreign body) making it more likely to be excreted in urine
- Ubiquitous - found everywhere (High in RBCs)
When a patient ODs we see toxics byproducts because we have ___
overwhelmed normal pathways & alternative pathways that are activated can have toxic by-products
What is the importance of pharmacogenetics?
The specific testing to help predict, explain, & treat
Warfarin is a __ mixture
Racemic mixture (R &S)
- S is 7-10x more potent than R
15-25% of breast cancers are caused by ___
HER2
What is the drug that targets breast cancers that are HER2 positive
Trastuzumab (Herceptin)
What is the Purine analogs MOA
blocks rapidly dividing cell from dividing
What is the role of drug transporters in the cell?
To transport endogenous & xenobiotic substances across barriers (membranes)
Role of Drug efflux transporters
Pump drug out of cell
Most of drug efflux transporters are
ATP - binding cassette transporters (ABC)
What are the three important ABC transporters?
ACBB1, ABCC, & ABCG2
Which ABC transporter has the broadest substrate specificity?
ABCB1
Which ACB transporter is the largest?
ABCC
Which way do transporters typically move in the Intestine?
Into cell (INFLUX)
Which way do transporters typically move in the Placenta?
Out of cell (EFFLUX) (alcohol can pass)
Which way do transporters typically move in the Liver?
Into cell (INFLUX) ; liver metabolizes most drugs; Liver –> bile
Which way do transporters typically move in the Kidneys?
Into cell (INFLUX) ; into glomerulus out through tubule excreted via urine
Which way do transporters typically move in the Blood Brain Barrier?
Out of cell (EFFLUX)
Which way do transporters typically move in the CSF?
Out of CSF (Efflux)
What are the components that protect the BBB?
- ABC transporters
- Vascular epithelium cells (tight junction)
- Cells that regulate what enters neuron (Astrocytes & Podocytes)
Barrier properties mediated by specific transporters in BBB are
- Active Efflux transporters (allows small lipophilic molecules - O2, CO2, Ethanol)
- Carrier Protein (allows glucose, amino acid nucleotides in)
- Receptor mediated (Insulin)
- Adsorption endocytosis (Albumin)
Delineate pathway of Tylenol in gut before & after bio-transformation
Tylenol absorbed through gut –> “First pass” goes to liver –> Phase 2 metabolism (glucuronidation adds glucose to it becomes nontoxic glucuronide) –> gets sent to bile –> Bile dumps it into intestine (ABC transporters) –> out through feces
What are parameters Affecting Passive diffusion?
- Molecular weight
- pKa
- Lipid solubility
- Plasma protein binding
Describe the pathways Acetaminophen can take upon metabolism
Normal pathways
- Glucuronidation –> non-toxic glucuronide (main pathway)
- Sulfation –> nontoxic sulfate
Alternative pathways
- GSH conjugation –> adds glutathione
- Nucleophilic cell macromolecules –> Liver cell death
If Drug1 is metabolized by CYP3A4; and CYP3A4 is induced, what affect would that have on drug1?
Drug1 would be inactivated much quicker
If a Prodrug is activated by CYP3A4; and CYP3A4 is induced, what affect would that have on the Prodrug?
The Prodrug would become active much quicker
If Drug1 is metabolized by CYP3A4; and CYP3A4 is inhibited, what affect would that have on drug1?
Drug1 would be more active (can lead to toxic levels)
If a Prodrug is activated by CYP3A4; and CYP3A4 is inhibited, what affect would that have on the Prodrug?
The Prodrug would remain inactive having no effect
What is a Prodrug?
A drug that has no biologic affect until it is metabolized
What drugs interact with ABCB1 transporters & what affect do they have on ABCB1?
Cyclosporine A, Quinidine, Ritonavir all inhibit ABCB1
What is Loperamide? & what effects does it have when combined with quinidine?
Loperamide - opioid, antidiarrheal no CNS effect BUT when combined with quinidine; quinidine inhibits ABCB1 –> Loperamide then has CNS effects (respiratory suppression)
Describe ABCG2 transporters
- breast cancer resistance proteins (BCRP)
- Antineoplastic, toxins, food borne carcinogens
- folate transport
Describe ABCB1 transporters
- broadest specificity (HIV protease inhibitors, ABX, antidepressants, antiepileptics & opioids)
- Wide distribution (GI, Kidneys, Liver & testes - Critical in BBB)
Describe ABCC transporters
- Largest class
- Mainly antineoplastic efflux
What is the enzyme that metabolizes Warfarin?
CYP2C9
If TPMT is mutated or missing, how will this affect the metabolism of 6-MP?
6-Mercaptopurine (6-MP) will increase & become toxic (TMPT is the main pathway for 6-MP metabolism)
What is an Allele?
alternative form of a gene which occurs at the same locus
Purine analogs are used to treat cancers & autoimmune disease but are toxic, why?
They suppress immune (myelosuppression) - narrow therapeutic index
If a patient has 2 copies of the TMPT gene, how does this affect how they take 6-MP?
It does not, they can take normal doses
If a patient has 1copy of the TMPT gene, how does this affect how they take 6-MP?
They need to take a reduced dose of drug
If a patient has 0 copies of the TMPT gene, how does this affect how they take 6-MP?
They will require another drug as they can not metabolism drug
What is the function of Solute Carrier (SLC) proteins?
Transport 15-30% of all membrane proteins
- High substrate specificity (Na, Glucose, Amino acids)
What is the function of SLC21
- Organic anion transporter proteins (OATPs)
- Primarily passive (gradients)
- some function for drug Influx
What affect would a poor metabolizer phenotype have on a Prodrug?
Prodrug would be inactive as it needs to be metabolized to work, poor efficacy –> possible accumulation of drug
What affect would a poor metabolizer phenotype have on an Active drug?
Active drug would stay active longer, good efficacy, can lead to toxic effects; may require lower dose
What affect would an Ultra-rapid metabolizer phenotype have on a Prodrug?
Prodrug would be active faster, good efficacy
What affect would an Ultra-rapid metabolizer phenotype have on an Active drug?
Active drug would become inactive rapidly, poor efficacy, will need greater dose
Describe the metabolism process involved in Cytochrome P450
Drug binds to P450 (contain iron) –> oxidation occurs –> electrons go to Flavoproteins (FMN) & becomes reduced & oxidized –> FMN is recycled by NADPH –> P450 & the drug are combined with hydrogen & oxygen to form H20 & an OH group attached to drug –> drug leaves HYDROPHILIC
60-70% of breast cancers express which type of receptors?
Estrogen receptors & Progesterone Receptors