Discussion Essay
Respond to at least two of your colleagues on two different days in one of the following ways:
- If your colleagues’ posts influenced your understanding of these concepts, be sure to share how and why. Include additional insights you gained.
- If you think your colleagues might have misunderstood these concepts, offer your alternative perspective and be sure to provide an explanation for them. Include resources to support your perspective.
Post a response to each of the following:
- Explain the agonist-to-antagonist spectrum of action of psychopharmacologic agents, including how partial and inverse agonist functionality may impact the efficacy of psychopharmacologic treatments.
- Compare and contrast the actions of g couple proteins and ion gated channels.
- Explain how the role of epigenetics may contribute to pharmacologic action.
- Explain how this information may impact the way you prescribe medications to patients. Include a specific example of a situation or case with a patient in which the psychiatric mental health nurse practitioner must be aware of the medication’s action.
Discussion 1 – Initial Post
Understanding a medication’s action and physiological effect is an essential skill for any prescriber to practice safely. This is especially true when prescribing psychiatric medications due to their impact on brain chemistry and function. APRNs should ensure that there is no possibility of harmful drug-drug interaction and adverse drug events when prescribing a new medication. Understanding the role of agonists and antagonist drugs is one way to reduce the risk of adverse drug events. A classic example is that the APRN would recognize that lithium would be contraindicated in a patient with a history of bipolar disorder and chronic hyponatremia due to lithium absorption increasing in the absence of sodium (Hedya et al., 2022).
Medications have two properties: affinity and intrinsic efficacy (Berg & Clarke, 2018). Affinity describes how well a drug can bind to a receptor and “is unique for each drug-receptor pair” (Berg & Clarke, 2018). Intrinsic efficacy describes the medications’ ability to affect the activity of the receptor and influence associated cell activity (Berg & Clarke, 2018). Agonist drugs possess affinity and intrinsic efficacy, while antagonist drugs have affinity but no intrinsic efficacy (Berg & Clarke, 2018).
Full agonist drugs change receptor activity to produce the maximum response, while a partial agonist can create a milder reaction (Berg & Clarke, 2018). Inverse agonists have the opposite effect of an agonist (Berg & Clarke, 2018; Nutt et al., 2016). Inverse antagonists were first observed in benzodiazepine animal studies, where certain drugs exacerbated anxiety and produced seizure activity in the animal test subjects (Nutt et al., 2016). Antagonist drugs have receptor-blocking or inhibitory effects, such as MAOIs or SSRIs, and are the most prescribed type of psychiatric drugs (Berg & Clarke, 2018; Nutt et al., 2016).
G-coupled protein receptors (GPCRs) and ion-gated channels both function as synaptic transmission sites; however, they differentiate from one another in that ion-gated channels open an ion channel and directly bind with neurotransmitters, while GPCRs signal a G-protein to indirectly bind with an ion channel (Alexander et al., 2011; Wang et al., 2018; Lakna, 2022). When GPCRs receive a chemical signal, they request either the binding to GTP to activate the channel, or GDP, to inactivate the channel (Wang et al., 2018). Ion-gated channels are located along the cell membrane and allow sodium, potassium, calcium, and chloride to pass directly through the cell membrane when signaled (Lakna, 2022).
The APRN must recognize the effect of epigenetics, or the changes to how a patient’s genes work due to environmental factors or personal behavior, and how these changes may impact the effectiveness of medication (CDC, 2022). Epigenetics most often affects messenger proteins that influence the messenger’s ability to activate or deactivate (CDC, 2022). The good news is that epigenetic changes are reversible and can be affected by changes to an individual’s environment or behavioral practices, such as changing a diet or quitting smoking (CDC, 2022).
References
Alexander, S. P. H., Mathie, A., & Peters, J. A. (2011). Ligand-gated ion channels. British Journal of Pharmacology, 164(1), 115-135. doi: https://doi.org/10.1111/j.1476-5381.2011.01649_4.xLinks to an external site.
Berg, K. A., & Clarke, W. P. (2018). Making sense of pharmacology: Inverse agonism and functional selectivity. International Journal of Neuropsychopharmacology,21(10), 962-977. doi: https://doi.org/10.1093%2Fijnp%2Fpyy071
ESSE
Post a response to each of the following:
- Explain the agonist-to-antagonist spectrum of action of psychopharmacologic agents, including how partial and inverse agonist functionality may impact the efficacy of psychopharmacologic treatments.
- Compare and contrast the actions of g couple proteins and ion gated channels.
- Explain how the role of epigenetics may contribute to pharmacologic action.
- Explain how this information may impact the way you prescribe medications to patients. Include a specific example of a situation or case with a patient in which the psychiatric mental health nurse practitioner must be aware of the medication’s action.
Week 2 Initial Discussion
Hello everyone,
The chemical that binds to the receptor is called the agonist hence the agonist maybe be a psychopharmacologic agent. Affinity is described as the ability of a drug to attach to the receptor and causes a change in the host cell. Agonists also possess efficacy which is determined by the ability to start up the receptor.
On the other hand, antagonist binds to receptors (affinity) but cannot activate the receptor, hence they lack efficacy. An antagonist inhibits an agonist from binding to the receptor, preventing its ability to activate the receptor (Weir, 2020).
Understanding: How I understand this is, someone overdosed on opioids (agonists) and is then given naloxone (antagonist).
A partial agonist does not produce the full response as an agonist which means it has less efficacy. I think an example of a partial agonist would be a nicotine patch. This is a partial dose of nicotine which reduces the efficacy of the drug nicotine compared to smoking a cigarette.
An inverse agonist causes the reverse effect of an agonist when a receptor is active without an agonist.
G-coupled proteins (GPCRs) are responsible for connecting the signal between agonist binding and activation of channels. While Ion gated channels control communication between neurons (Stern et al., 2016).
Research has shown that some diseases are able to be identified early in life via epigenetics. When the disease has been identified scientists are able to develop personalized drugs (Gianfrancesco et al., 2019).
When prescribing medications to patients it is important to have a thorough history. It would also be wise to obtain labs (CBC, BMP, kidney function, liver panel, and thyroid) to identify a baseline. For example, lithium has been known to cause renal failure (Schoot et al., 2020). However, it may not be the best option for a patient with renal disease or a patient with elevated creatinine.
References
Gianfrancesco, O., Bubb, V. J., & Quinn, J. P. (2019). Treating the “E” in “G × E”: Trauma-Informed Approaches and Psychological Therapy Interventions in Psychosis. Frontiers in Psychiatry, 10. https://doi.org/10.3389/fpsyt.2019.00009 Links to an external site.
