Quiz 1 Exam 2 Flashcards
Define drug resistance.
Drug resistance is the development of a reduced drug response.
What are the 5 causes for drug resistance?
- Increased efflux (PK)
- Decreased uptake (PK)
- Drug inactivation (PK)
- Mutations in the drug target (PD)
- Reversal of drug action (PD)
__________ is an example of intrinsic drug resistance.
MRSA (Methicillin-resistant Staphylococcus aureus)
Intrinsic in terms of drug resistance means it will have no initial response to the drug.
What is intrinsic drug resistance?
This is the innate ability of a species to resist the action of a drug as a consequence of the structural or functional characteristics of that species
What is acquired drug resistance?
Occurs when the species acquires the ability to resist the actions of a particular drug
What is an example of a ligand-gated ion channel?
The nicotinic receptor. This receptor is bound by acetylcholine and allows for the passage of Na+ into the cell.
How many subunits are on the nicotinic receptor?
5 subunits; 2 alpha, 1 beta, 1 gamma, and 1 delta unit.
Where does acetylcholine bind on the nicotinic receptor?
Acetylcholine molecules bind to the 2 alpha subunits on the nicotinic receptor.
In the human genome, ______- _______ genes code for transport proteins.
500-1200
What is a basolateral membrane?
The basolateral membrane has contact with the blood vessel and the epithelial cell.
What is an apical membrane?
The apical membrane is the surface of the cell that faces the lumen.
Are transporter/carrier proteins faster or slower than ion channels?
Transporter/carrier proteins are much slower than ion channels as they are more complex.
What are the two types of transporter-carrier proteins?
Active (require energy and go against conc. gradient) and passive (no energy and go with conc. gradient)
What is the main efflux transporter?
ABCs (ATP-Binding Cassette Proteins)
What are the main uptake/influx transporters?
SLCs (Solute Carrier Family)
Efflux transporters like the ABCs contribute to __________________.
Multi-drug resistance
Efflux transporters like ABCs typically contain __ nucleotide bindings domains and at least 2 _______________ domains.
2
Transmembrane
What do the transmembrane domains on efflux transporters like the ABCs define?
The transmembrane domains on ABCs define substrate specificity, which is typically very broad.
What is the evolutionary reason for the development of efflux transporters?
They prevent toxins from entering vital organs at BBB, BTB, placenta, and ovaries.
What are the 3 genes families of efflux transporters?
- MDR1 (ABCB1, p-glycoproteins)
- MRPs (Multi-drug Resistance Proteins)
- MXR (BCRP-breast cancer resistance protein)
Increased activity of multi-drug resistance pumps like ABCB1, ABCC1, and ABCG2 _________ resistance to anti-cancer drugs.
Increases
(B1, C1, and G2)
How do ABC efflux transporters transport things out of the cell?
They bind ATP and become a barrel shape to form a pore with a 5 nanometer diameter.
What are the general characteristics of substances effluxed by MDR1/ ABCB1/ p-glycoprotein?
Hydrophobic neutral and cationic compounds. Very broad in general though.
What are the 4 compounds discussed that inhibit MDR1?
Tamoxifen
Progesterone
Cyclosporin A
Quinidine
What are the 3 discussed SLC uptake transporters?
- Organic cation transporters (OCTs)
- Organic anion transporters (OATs)
- Nucleoside transporters
What is the function and type of organic cation transporter located at the basolateral membrane of renal epithelial cells?
OCT1:
Uptake organic cations from the blood which is the 1st step of renal excretion. Found also in tubular epithelium.
What is the function and type of organic cation transporter located in hepatocytes?
OCT1:
Uptake cations into liver cell which is the 1st step before drug metabolism.
What is the function and type of organic cation transporter located in the brain?
OCT2:
Transport of monoamine NTs like dopamine. They reuptake NTs into the presynaptic site.
OCT3:
Transport serotonin
What is the function of the organic anion transporters in the liver?
They mediate the uptake of bile acids.
What is the function of the organic anion transporters in the renal epithelial cells?
They uptake organic anions which is the first step in renal secretion.
What is the function of the nucleoside transporters in the SLC family?
They uptake purine and pyrimidine nucleosides. There are some that are equilibrative (no energy) and concentrative (need energy).
Which family member of the SLCs is responsible for the uptake of nucleoside analog drugs?
Nucleoside transporters
This nucleoside transporter, _______, is important in determining the response to nucleoside analongs with ____________ properties.
ENT2
Anti-retroviral
Low expression/ low activity polymorphisms in ___________ (reduced folate carrier) _______ patients to methotrexate.
SLC19A1
Densensitize
MDR-1/ P-glycoproteins in the brain is associated with __________ and ___________ to nortriptyline.
Drug-resistant epilepsy
Postural hypotension
The goal of asymmetrical distribution of transporters on the BBB is to ____________________.
Shuttle things out rather than shuttle them in.
What are 3 molecules that use transport proteins to pass the BBB?
Glucose, AA, and nucleosides
What are 2 molecules that use receptor-mediated endocytosis to pass the BBB?
Insulin and transferrin
What are 2 things that use adsorptive endocytosis to pass the BBB?
Albumin and other plasma proteins
In terms of drug inactivation, what does a beta-lactamase do?
Beta-lactamase (penicillinase) inactivates antibiotics via hydrolysis.
In terms of drug inactivation, what does N-acetyltransferase do?
NATs transfer chemical groups. An example of this is isoniazid.
What are the 3 enzymatic ways in which drug inactivation in drug resistance is mediated?
Hydrolysis, group transfer, and redox mechanisms
In terms of drug inactivation, what does Thioredoxin do?
Thioredoxin inactivates peroxides by serving as an electron donor to peroxidases.
What are redox-cycling antibiotics?
Antibiotics that kill the pathogen through redox cycling by generating free radicals to kill the bacteria.
How do some pathogens combat redox-cycling antibiotics
Pathogens have increased levels of glutathione transferase which detoxifies peroxidases and underlie antibiotic resistance.
CYP3A4 oxidizes common chemotherapeutic drugs to inactivate them like _________ and ___________.
Ifosfamide and cyclophosphamide
CYP3A4 oxidizes common chemotherapeutic drugs to activate them like _________ and ___________.
Etoposide and doxorubicin (prodrugs)
In human DNA, genetic information is stable. There are DNA repair mechanisms that reverse mutations. In cancer cells, DNA is less stable due to defects in DNA repair called _______________.
Mutator phenotype
Drug target __________ affect drug action.
Mutations
Gleevec (imatinib) is a small molecule kinase inhibitor that target BCR-ABL in chronic myeloid leukemia. However a common mutation in ___________ makes BCR-ABL resistant to this drug and others.
T315I
Some oncogenes suppress _____________
Apoptosis (programmed cell death)
The abundance of ________ family proteins resist apoptosis.
BCL-2 (pro-surivival)
The _______ domains of the pro-apoptotic BCL-2 family members can ____________ anti-apoptotic BCL-2 family proteins.
BH3
neutralize
An example of a DNA repair mechanism is _____________.
Nucleotide excision repair
What is nucleotide excision repair?
A mutation is sensed in DNA and a repair molecule is sent to fix it. Eventually several molecules, cut the DNA from both side and resynthesize the correct DNA.
Nucleotide excision repair contribute highly to ________ life expectancy.
increased
In cancer cells with intact DNA repair, what drugs should be avoided?
Avoid drugs that cause injury to the DNA like conventional anti-cancer drugs include alkylating agents as the cell can still repair the DNA damage.
_____________ protects cells from alkylating agents via DNA repair.
MGMT
Drug resistance could be overcome by depletion of ___________.
MGMT
Define transduction in terms of genetic pathogen drug resistance.
Transduction is when a bacteriophage can transfer a resistant gene from one bacterium to another, even across different species.
Define transformation in terms of genetic pathogen drug resistance.
Transformation is when fragments of free DNA like plasmids, in the environments can be taken up.
Define conjugation in terms of genetic pathogen drug resistance.
Conjugation is the transfer of genetic material between 2 bacteria.
What is HAART in HIV therapy?
2-3 Nucleoside analogs
1-2 Protease inhibitors or 1 RT inhibitor
What are the 2 main functions of SSRIs?
- Desensitize presynaptic receptors
- Block feedback-inhibition of serotonin release
Define desensitization.
Desensitization is the induction of a temporary state of tolerance. The initial response to the agonist is good but it gradually diminishes with time. Desensitization reversies with removal of the agonist.
What are the 2 mechanism of desensitization?
- Change in receptor (agonist-induced changes diminishes ability of receptor to interact with G proteins)
- Loss of receptors (internalization of receptors into endocytic vesicles)
Desensitization is a ____________ response.
Rapid
Define tolerance.
Tolerance is the repeated administration that progressively reduces the effect of a drug.
T or F: Tolerance cannot be overcome and is not reversible.
False.
Tolerance can be overcome with a dose increase and is reversible after discontinuation of a drug.
What are the 2 mechanism of tolerance?
- Accelerated metabolism and disposition (PK tolerance)
- Loss of efficacy through changes in the drug target (PD tolerance)
Tolerance is __________ while desensitization is __________.
Chronic
Acute
Pharmacokinetic examples of tolerance include…
Reduced absorption
Altered distribution
Increased metabolism
Increased excretion
Pharmacodynamic examples of tolerance include…
Reduction in receptor number
Reduced affinity
Altered signal transduction
What are the differences between tolerance and resistance?
Tolerance and resistance both represent a lack of responsiveness but resistance cannot be overcome by a dose increase and is not reversible through discontinuation of a drug.
Define cross-tolerance.
Cross-tolerance occurs when someone is tolerant to the effects of a certain drug and also develops a tolerance for another drug (typically seem with drugs that have similar functions and effects).
Define dependence.
Dependence means that a continued presence of a drug is required for normal functioning.
What 2 things occurs with dependence?
Tolerance and withdrawal
What is physical dependence?
This is an abstinence syndrome due to an altered physiological state.
What is psychological dependence?
This means there is an emotional drive or craving for the drug which may lead to compulsive drug use.
Define withdrawal.
Withdrawal is a physiological response to the termination of drug therapy (abstinence syndrome)
What is the difference between withdrawal and tolerance?
Withdrawal includes cravings while tolerance does not include cravings.
Neonates and newborns consist of up to ______% body water which is mostly extracellular fluid.
70
Neonates and newborns are more likely to become ___________ due to the large amount of extracellular body water.
Dehydrated
The adult extracellular fluid is around _______%.
20
Water-soluble drugs like acetaminophen are more __________ in a child than in an adult.
Dilute
As growth occurs in different life stages, total body water ___________ but blood volume ___________.
Increases
Decreases
Surface area to volume ratio ___________ with increased weight.
Decreases
Does glomerular filtration rate decrease or increase with age?
It increases when referring to neonates to adults
The mL/kg blood volume is determined by weight and _________ as a child grows.
decreases
What is the typically blood volume in a neonate?
85-90mL/kg
What do both children and elderly struggle with when taking medications?
Swallowing solids is difficult
T or F: Most requirements are very similar in the pediatric and geriatric population.
True
What are 3 functions that are reduced in the geriatric population?
- Reduced albumin synthesis (reduced plasma-protein drug binding)
- Reduced kidney and liver function (slower drug elimination)
- Reduced cardiovascular function
What can result in the geriatric population due to their decreased cardiovascular function?
They will have an increased response to beta-blockers and anti-hypertensives.
T or F: Hepatic enzymes are mature in the pediatric population.
False. Hepatic enzymes are not mature in this population.
What is the kidney filtration rate in the pediatric population?
2mL/kg/hr compared to adults which is 0.5-1mL/kg/hr
Do children need more oxygen?
Yes. Children need 6mL/100g/min as their CNS is still developing.
T or F: The BBB is less permeable in the pediatric population?
False. The BBB is more permeable
Adult hearts can compensate with increasing heart rate and volume which children can only compensate with _________.
Increased heart rate leading to tachycardia.
What is the typical pulse and respirations in premature and newborn infants? Is this slower or faster than adults?
Premature: 140+, 30-40 respirations
Newborn: 120-160, 30-50 respirations
Both are these are much faster than adults
What is the rule of 6’s?
This is a rule for mixing drug infusions. 6 steps and one multiplication by 6.
During drug elimination involving both metabolism in the liver and excretion within the kidneys and intestines, can the drug act on the tissues?
No
What are the 4 main functions of the liver?
- Synthesis- bile, clotting factors, albumin
- Storage- glucose, vitamins, minerals
- Phagocytosis- blood cells
- Intracellular enzyme proteins
What two drug can inhibit CPY450s responsible for the metabolism of metoprolol and warfarin?
Paroxetine and fluoxetine
What is meant by a class of drugs?
Drugs in the same class have the same MOA but different PKs and safety.
________________, like ritonavir and indinavir inhibit what enzyme and can lead to increased levels of drugs like nifedipine.
HIV-1 Protease inhibitors
CYP3A
How does the administration of a lipophilic drug in an obese patient differ than the administration of a lipophilic drug in a patient with a normal BMI?
It is difficult to reach steady state in obese patients- Adipose tissue takes up lipophilic drugs, making it difficult to reach steady state. Once adipose tissue is saturated, you must be careful to not overdose the patient. Giving mg/kg dose is more
accurate than a ‘one size fits all’ dose.
How does the body water composition differ in neonates/newborns in comparison to
adults?
Most of the body water in in neonates/newborns is extracellular
What is drug disposition?
This is how we get rid of the drugs via metabolism and excretion.
Does hepatic and/or renal impairment affect drug disposition?
Renal and/or hepatic impairment can impact drug disposition and require an adjustment in dosing.
What are the two ways in which hepatic dysfunction manifests?
Hepatocellular disease and Cholestatic disease
What is hepatocellular disease?
This includes liver disease, inflammation, and necrosis. Overall liver dysfunction.
What is cholestatic disease?
This is bile flow inhibition due to gallstones, malignant obstruction, primary biliary cirrhosis, and certain drugs.
T or F: Liver disease does not cause drug accumulation.
False. Liver/ hepatic disease causes drug accumulation as well as drug activation.
What are the 5 measures of the Child-Pugh liver dysfunction classifications?
- Total bilirubin
- Serum albumin
- PT INR (Prothrombin International Normalized Ratio)
- Ascites
- Hepatic Encephalopathy
Do N-acetyltransfereases (NAT1 and NAT2) have small or large substrate specificity?
Large substrate specificity
N-Acetyltransferases have an impact on the predisposition to drug ___________ and ___________.
Efficacy and toxicity
What is the main hazard surrounding renal impairment?
Compromised drug elimination
What is the advanced stage hazard of renal impairment?
- Kidney has altered metabolic capacity
- Production of nephrotoxic compounds
What is the main measurement of renal impairment?
Estimated creatinine clearance (mL/min)
What is the creatinine clearance for normal renal function?
> 80mL/min
Why is creatinine clearance used as the measurement for renal impairment?
Creatinine is ONLY cleared by the kidneys.
What is the equation for creatinine clearance?
Androgens ______________ drug metabolism while estrogens ______________ drug metabolism.
Increase
Decrease
Cardiac output in women is _______________% less than in men.
10-20%
The ______________ cycle affect drug responses including fluctuations in p-glycoproteins.
Menstural
___________ is absorbed more slowly in women than in men.
Aspirin
The ___________ of drug _________ and ____________ for heart function are slower in women.
Renal clearance
Quinine and Quinidine
__________ relieves symptoms of IBS in women but NOT in men.
Alosetron
____________ is more effective in men.
Ibuprofen
The painkiller/opioid ___________ is more effective in women.
Pentazocine
What is chronopharmacology?
This is the how the metabolism fluctuates with circadian rhythm.
Steroid hormones fluctuate __________.
Diurnally
During what time period does cholesterol levels peak?
PM
Gastric acid peaks during the _________ time period. Therefore, _____________ blockers should be given at night.
PM
Histamine (H2)
______________ are more frequent in the AM. Therefore, products like ____________ and ___________ are given at night and designed to be absorbed in the early AM.
Angina and Heart Attacks
Covera-HS and Verelan PM (Verapamil products)
What drug was designed to dampen the morning insulin spike, should be taken within 2 hours of waking, and has been unsuccessful?
Bromocriptine
What are the two factors that affects the antibiotic drug response?
- Genetic predisposition in the host
- Pathogen genomics including virulence and anti-infective resistance
What is virluence?
Virulence is the capability of the pathogen to cause disease in the host overtime.
Typically as pathogen develop, their infectivity and ability to procreate ___________ while virulence __________. This is how COVID has developed.
Increases
Decreases
T or F: Polymorphisms are disease causing.
False. Polymorphisms themselves are not disease causing.
Polymorphisms in what gene for pathogen detection effect the response to meningococcal bacteremia?
Mannose binding lectin on codons 52, 54, and 57.