G-Protien coupled receptors and how they interact with drugs
G-protein coupled receptors (GPCR) interact with drugs through 7 regions of proteins that span and innervate the cell membrane and trap the molecule into the receptor site like an interwoven basket (Insel & Sriram, 2018). Drugs can then ...
NR 565 Midterm
G-Protien coupled receptors and how they interact with drugs - Answer G-protein
coupled receptors (GPCR) interact with drugs through 7 regions of proteins that span
and innervate the cell membrane and trap the molecule into the receptor site like an
interwoven basket (Insel & Sriram, 2018). Drugs can then enter this space and interact
with the GRCP. A specific interaction and binding with a site on one or more of the
regions of proteins within the GPCR, and drugs bound with the GRCP can stimulate the
release of G proteins that can interact with various effector proteins to create
physiological responses within the body (Insel & Sriram, 2018). This process occurs
through secondary messengers (such as cAMP) which creates the extracellular
interactions produced by the drug binding to the GRCP.
What neurotransmitters are excitatory? - Answer amino acids such as glycine,
aspartate, and glutamate are excitatory (Woo & Robinson, p.16, 2016).
Which is the most common CYP enzyme in the body? What role does it play? - Answer
According to the textbook, the CYP3A4 is the most important enzyme in the body.
CYP3A4 is responsible for the metabolism of more than 50% of medications and is
considered a major drug metabolizing enzyme. CYP3A4 can be found in the liver, as
well as the lining of the GI tract. Due to this location, food can also influence this CYP.
One example of this is grapefruit juice, which can inhibit CYP3A4. Medications that are
metabolized by CYP3A4 include antimicrobials, calcium channel blockers,
antihistamines, anticonvulsants, azole antifungals, and corticosteroids (Woo, &
Robinson, 2016).
What is the clinical significance of being an ultra-rapid CYP2D6 metabolizer? - Answer
People who are ultra-rapid metabolizers have high activity of CYP2D6 enzymes that
break down certain medicines rapidly and are likely to need different doses or even a
different medicine. Drug dose, response, and toxicity risk of beta-blockers,
antidepressants, antiarrhythmics, and opioid analgesics are dependent on CYP2D6
pharmacogenetics (Ayazseven et al., 2020). Knowing the result of the CYP2D6 test and
which group the patient falls into such as poor metabolizers, intermediate metabolizers,
or ultra-rapid metabolizers, will help nurse practitioners prescribe the right medication
and dosage for the patient.
What would be the concern if a drug is a CYP450indicer? How that might affect the
metabolism of another drug the patient is taking? - Answer Cytochrome P450 enzymes
are in cells throughout the body, primarily found in liver cells (Girvan & Munro, 2016).
These enzymes are essential for the metabolism of many medications. Cytochrome
P450 enzymes can act as an inducer or inhibitor of metabolism. When a medication
induces the CYP450 enzyme that increases the rate of metabolism (Girvan & Munro,
2016). This can impact the effectiveness of other medications. For example, medication
A induces CYP450 enzyme activity, therefore medication B will be metabolized quicker
and have a less therapeutic effect.
Explain the significance of a drug being an inhibitor of P-glycoprotein? (see text) -
Answer P-glycoprotein (P-gp) is the main barrier of the body and it affects the proper
, NR 565 Midterm
delivery of drugs and causes drug resistance in our body. P-gp is an efflux membrane
transporter, that can be found throughout the body and it controls the cellular uptake
and the distribution of synthetic substances, chemicals, and toxins. Drugs are chemicals
and P-gp hinders the absorption, permeability, and retention of the drugs, extruding
them out of the cells. This adversely affects drug therapies and fails to yield good
results, for example in therapies like using chemo agents in cancer treatments. In this
case, proper inhibition of P-gp is important to increase cellular uptake, transport, and
half-lives of drugs. The drug is an inhibitor of P-gp that would help in the cost-effective
treatment for disease conditions without wasting an extra amount of medicines. It will
help to shorten the treatment time and speedy recovery of the patient (Abebe et al.,
2019; Woo & Robinson, 2016).
Significance of a VCORC1 mutation for patients taking warfarin? - Answer In 2008, the
U.S Food and Drug Administration updated the dosing of warfarin to include the
application of pharmacogenomics. Variable metabolism by CYP2C9 was once known
as the major contributor to the variable response to warfarin. However, a mutation in
VCORC1 has been found to account for much more variability in warfarin responses
and can cause a rare syndrome of warfarin resistance. A mutation in VCORC1 encodes
a subunit of the vitamin K epoxide reductase complex ,the pharmacological target for
warfarin, and increases the chances of uncontrolled bleeding (Woo & Robinson, 2016).
Therefore, if providers have information about the presence of this mutation, they may
decide to decrease the dosage of Coumadin for their patient.
What out text has to say about National Standards of Culturally and Linguistically
Appropriate Services? - Answer In 2012, the institute of medicine identified that the
main factor affecting health disparity is cultural competency of the health practitioner
(Woo & Robinson, 2016). The National Standard for Culturally and Linguistically
Appropriate Services in health and health care (CLAS) standards were created as a
way to address and correct these inequities (Woo & Robinson, 2016). Originally
established in 2000, the CLAS standards provided a blueprint for providers to
implement services that were culturally and linguistically appropriate, however, over the
years they have evolved (Woo & Robinson, 2016). They have undergone review and
have been revised in 2013 and will continue to evolve in response to research and
changing demographics (Woo & Robinson, 2016).
What are some differences in drug metabolism in Asian populations? - Answer One of
the biggest differences in drug metabolism derives from the fact that Asian populations
typically have reduced activity of the CYP450 2D6 and 2C19 enzymes (Woo &
Robinson, 2016). Specifically, the 2D6 isoenzyme is responsible for metabolism of
antiarrhythmics, antidepressants, and neuroleptics so the metabolism of these drugs
are slower than other racial groups (Woo & Robinson, 2016). Given that, the clinician
would need to make sure they monitor this patient and adjust dosages as appropriate.
The 2C19 isoenzyme is responsible for metabolism of acids, bases, and neutral drugs
(Woo & Robinson, 2016). Similarly to the 2D6 discussion above, these drugs may need
lower dosages due to the slower metabolism of them. The text also discusses that some
Asian subgroups are considered "fast acetylators" of drugs such as psychotropic and
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