Posted: November 29th, 2022

Pharmacodynamics and pharmacokinetics (PD/PK)

Read a selection of your colleagues’ responses and respond to at least two of your colleagues on two different days by suggesting additional patient factors that might have interfered with the pharmacokinetic and pharmacodynamic processes of the patients they described. In addition, suggest how the personalized plan of care might change if the age of the patient were different and/or if the patient had a comorbid condition, such as renal failure, heart failure, or liver failure. OR
Post a description of the case you selected. Then, describe factors that might have influenced pharmacokinetic and pharmacodynamic processes of the patient from the case you selected. Finally, explain details of the personalized plan of care that you would develop based on influencing factors and patient history in your case.
Read a selection of your colleagues’ responses and respond to at least two of your colleagues on two different days by suggesting additional patient factors that might have interfered with the pharmacokinetic and pharmadynamic processes of the patients in their case studies. In addition, suggest how the personal care plan might change if the age of the patient were different and if the patient had a comorbid condition such as renal failure, heart failure, or liver failure.
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Sample Answer:
Pharmacodynamics and pharmacokinetics
The patient I’m describing in this case is a 70-year-old African-American man who had rheumatoid arthritis. The patient has had arthritis for 20 years and has been on medication to slow the progression of the disease since it was diagnosed. Nonsteroidal anti-inflammatory drugs, hydroxychloroquine for pain, and methotrexate to slow disease progression are among his medications.
There are factors that influence the pharmacokinetics of the drugs he was taking. Many patient-related factors influence bioavailability, absorption, distribution, metabolism, and distribution. These factors include the patient’s age, which is associated with polypharmacy, the patient’s nutritional status, compliance, drug interaction, and the presence of other comorbidities. The action of drugs on the body, as well as their biochemical and physiological effects (i.e., pharmacodynamics), are influenced by factors such as patient age, race, and pre-existing co-morbidities such as renal disease. (2021, Rosenthal)
In this case, personalized care is required to ensure that the patient experiences the least amount of pain, the least amount of debility, and the least amount of disease progression. Nonsteroidal anti-inflammatory drugs are effective for arthritic pain, but they increase the risk of peptic ulcers. If this is the case, hydroxychloroquine can be used instead. Methotrexate is typically cytotoxic, and its effects must be carefully monitored to avoid toxicity (Rosenthal, 2021). It also causes vomiting and hair loss as side effects. If there is significant joint damage causing loss of function, surgical management will be an option.
The patient I’ll be discussing in this case was one I cared for on a cardiac step-down unit. This patient had end-stage renal failure and required dialysis on a daily basis. They had skipped dialysis for the previous three days. Heart failure, high cholesterol, hypertension, and cardiac arrhythmia were among the co-morbidities. The patient presented to our unit with chest pain and shortness of breath and required emergent inpatient dialysis. The patient had severe hypertension. Before arriving at the ER, the patient had not taken any of their prescribed morning medications. The attending physician prescribed an oral hypertensive medication dose for the patient to take at home. The nurse administered. Shortly after, the patient developed severe bradycardia and loss of consciousness, necessitating the administration of atropine IV to increase the heart rate. This patient’s pharmacokinetics and pharmacodynamics are being influenced by a number of factors.
This patient’s renal drug excretion was hampered by their end-stage renal failure and need for dialysis. They were three days behind schedule, and the patient’s blood pressure medication had accumulated and could not be filtered and excreted through the kidneys due to missed dialysis appointments. When renal failure occurs, the duration and intensity of a drug response may increase (Rosenthal &Burchum, 2021). Due to the reduced drug excretion and prolonged half-life, it also dangerously reduced the patient’s heart rate while treating his blood pressure. Cardiac rhythm monitoring has revealed that bradyarrhythmias are the most common clinically significant arrhythmias in hemodialysis patients (Roehm et al, 2020). Treating patients with heart failure, high blood pressure, and end-stage renal disease can be extremely difficult, especially if the patient is not adhering to medication and appointment schedules.
Knowing the patient’s home dose and last dose taken would aid in calculating the medication’s elimination half-life. Given that this is a renal patient, the half-life would be even longer and absorption would be compromised. This suggests that a medication dose may be too high in patients with HF and advanced kidney dysfunction, and that the dose should be reduced or the dosing interval extended (Kida et al, 2015).
In my case study, I discussed this acute care inpatient hospital patient. If this were a patient of mine in a non-acute primary care clinic setting, the management would be slightly different. Patients with end-stage renal disease have a variety of symptoms, and many of them are often intertwined with or exacerbated by underlying comorbidities, making medication selection difficult. Given that patients with renal disease rely heavily on medication strategies to manage their symptoms, medication selection and management necessitate appropriate follow-up and monitoring by all members of the healthcare team (Cho et al, 2020).
Assignment on Pharmacokinetics and Pharmacodynamics

As an advanced practice nurse Helping physicians with disorder diagnosis and treatment, it is critical to understand not only the impact of disorders on the body, but also the impact of drug treatments on the body. Pharmacokinetics and pharmacodynamics describe the interactions between drugs and the body. Pharmacokinetics is concerned with what the body does to the drug via absorption, distribution, metabolism, and excretion, whereas pharmacodynamics is concerned with what the drug does to the body. Image courtesy of Getty Images/Ingram Publishing Individual patient factors that may impact the patient’s pharmacokinetic and pharmacodynamic processes must be considered when selecting drugs and determining dosages for patients. Genetics, gender, ethnicity, age, behavior (e.g., diet, nutrition, smoking, alcohol, and illicit drug abuse), and/or pathophysiological changes caused by disease are examples of patient factors. You will reflect on a case from your previous clinical experiences for this Discussion and consider how a patient’s pharmacokinetic and pharmacodynamic processes may alter his or her response to a drug. To Get Ready Examine the Resources for this module and think about pharmacokinetics and pharmacodynamics. Consider your recent experiences, observations, and/or clinical practices, and consider how pharmacokinetic and pharmacodynamic factors changed his or her anticipated response to a drug. Pharmacodynamics and pharmacokinetics Assignment. Consider factors such as genetics (including pharmacogenetics), gender, ethnicity, age, behavior, and/or possible pathophysiological changes caused by disease that may have influenced the patient’s pharmacokinetic and pharmacodynamic processes. Consider a personalized plan of care in your case study based on these influencing factors and patient history. By the third day of Week 1, Post a description of a patient case from your recent experiences, observations, and/or clinical practice. Then, describe any factors that may have influenced the patient’s pharmacokinetic and pharmacodynamic processes. Finally, describe the personalized plan of care that you would develop in your case based on influencing factors and patient history. Provide specifics and examples.
More Case study:
I was caring for a 78-year-old African-American male hypertensive patient who was on calcium channel blocker and thiazide. He complained about bloody feces and abdominal pain. He rated his pain as 10/10, had a blood pressure of 122/78mmHg, and appeared dehydrated and emaciated. He had an endoscopy, which revealed that he had a malignant growth.

Pharmacodynamics and pharmacokinetics
Pharmacokinetics is the study of drug absorption, distribution, metabolism, and excretion. According to Effinger et al (2019), this patient’s drug absorption rate can be affected by obstruction by an esophageal tumor affecting the GIT lining and the chemotherapy administered. If the drugs administered are lipophilic, the distribution of the drugs will be poor or decrease due to a decrease in fat content (Almazroo, Miah & Venkataramanan, 2017). The bioavailability of a drug is highly dependent on its state, especially for drugs metabolized in the liver. In this patient’s case, the liver profile may be compromised due to liver metastasis, and genetic testing is required before starting chemotherapy to determine if he is a fast-metabolizer. Assignment on Pharmacokinetics and Pharmacodynamics

The rate of drug excretion is determined by the excretory pathway, that is, whether the drug is excreted through the liver, the kidneys, or the skin. The kidney’s functionality is important because it is the main organ for drug excretion and can be affected by hypertension. Pharmacodynamics is defined by Keller and Hann (2018) as the dose-response relationship or effect of a drug on the body. This includes observing the doses that can produce beneficial effects as well as the frequency required to achieve the desired effect. Given his dehydration, this patient’s old age and hypertensive state may impair the effect of antihypertensive (thiazide diuretic) on blood pressure control. As a result, it is critical to adhere to the recommended dosage of antihypertensives.
Plan your own care
Diagnosis
The patient described above is hypertensive, dehydrated, emaciated, and unable to eat solid foods.
Goals and Results
-Within 48 hours, the patient’s hemoglobin level will be greater than or equal to 7.
Within 72 hours, the patient’s input will equal the output, as evidenced by a shift in I/O reports.
Within 48 hours, the patient’s mucous membranes will be moist, as evidenced by documentation.
The patient’s pain level will be less than 5/10 out of a possible 10/10.
Intervention
A Complete Blood Count (showed thrombocytopenia and anemia), Renal Panel (within normal range), and Lipid Panel were ordered (elevated AST, ALT)
IV (intravenous) access
Insert NGT here (nasogastric tube)
Transfuse two units of packed red blood cells (RBCs) to the patient and recheck the HGB one hour after the transfusion.
Begin IV rehydration with Normal Saline at a rate of 150cc/hr for 24 hours.
Every hour, accurately record the I/O.
Assess pain with IV morphine 5 mg every 4 hours.
Work with a clinical nutritionist and an oncologist to improve the patient’s nutritional status and begin cancer treatment. Assignment on Pharmacokinetics and Pharmacodynamics
References
O. A. Almazroo, M. K. Miah, and R. Venkataramanan (2017). The liver is responsible for drug metabolism. 1-20 in Clinics in Liver Disease, 21(1).
A. Effinger, C. M. O’Driscoll, M. McAllister, and N. Fotaki (2019). A PEARRL review of the impact of gastrointestinal disease states on oral drug absorption and the implications for formulation design. 71(4), 674-698, Journal of Pharmacy and Pharmacology.
F. Keller and A. Hann (2018). Clinical Pharmacodynamics: Drug Response Principles and Kidney Disease Alterations The American Society of Nephrology’s clinical journal, CJASN, 13(9), 1413-1420. https://doi.org/10.2215/CJN.10960917
Week1 Discussion Rubric
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Sample 3
Providing care to our patients as a nurse practitioner necessitates that we as clinicians understand the pathophysiology of the disease as well as the pharmacology of the drugs used to treat conditions. While each patient is unique and can be complicated at times, understanding the pharmacokinetics and pharmacodynamics is critical for treatment. The impact of the body on drugs is the foundation of pharmacokinetics, which is the process of moving drugs to their sites of action throughout the body (Arcangelo, Peterson, Wilbur & Reinhold, 2017, p. 17). Understanding how medications are circulated, administered, absorbed, and eventually discarded from the body is required. Arcangelo, Peterson, Wilbur, and Reinhold (2017), on the other hand, define pharmacodynamics as the effects of drugs on the body; this is the toxic or therapeutic effect of drugs at the systemic or cellular level (p. 17). Practitioners or providers must understand the drug’s processes and apply them to the individual or patient. Providers must comprehend advanced pharmacology principles and be able to apply them in practice (Laureate Education, 2012). A 65-year-old male presented with an exacerbation of congestive heart failure. Patient A had increased swelling in the lower extremities, resulting in pitting 3+ pitting edema and increased shortness of breath. The patient was found to have and fluid in the lungs, as well as bilaterally diminished breath sounds in the lower lobes. Patient A’s medical history was extensive, including prior open-heart surgery, x4 vessels, hypertension, stage IV kidney disease, and diabetes. The patient was in hospice care and was taking the maximum dose of Lasix to combat fluid buildup.

Individual Variables
The importance of the pharmacokinetic process is in delivering drugs to the sites of action where they can produce pharmacodynamic effects (Arcangelo, Peterson, Wilbur & Reinhold, 2017, p.17). Behavior and pathophysiological changes played a significant role in this situation, which resulted in Lasix pharmacokinetic disruption. While there is a wealth of information available about Lasix and its effectiveness in reducing fluid in the body, there is also extensive information available about the drug’s toxic effect on the kidneys. Fluid retention is common in patients with congestive heart failure, and Lasix is typically the drug of choice. However, it is critical that providers ensure that the kidneys’ health is being monitored.
According to preliminary data, aggressive loop diuretics are capable of negatively activating neurohumoral pathways, resulting in renal blood flow impairment and glomerular filtration rate (GFR) decrement (Kuzner, 2013). The glomerular filtration rate is a test used to determine whether the kidneys are functioning properly. One of the factors influencing fluid buildup was behavior. Even though his medical conditions required it, the patient was not limiting the amount of fluids he consumed. Genetics also played a role in the effectiveness of Lasix medication in terms of kidney failure and fluid buildup in the body. Due to the presence of kidney failure, the patient was more vulnerable to kidney damage from the high dose of Lasix.
It is critical in the health care profession that we understand disease pathophysiology as well as the pharmacotherapeutics involved in caring for our patients. As a result, Hilmer, McLachlan, and Le Couteur (2007) argue that prescribing for geriatric patients necessitates thorough and advanced knowledge of the effectiveness of medications in weak and highly vulnerable older people, risk Assessment of side effects, deliberation on the cost-benefit ratio while consulting the patients, a decision on dosage regimes, and vigilant monitoring of the patient’s response.
In this particular case, a personalized care plan was created and implemented for the patient’s care. The care plan incorporated the patient’s history and adjusted the medications available to treat the disease’s current manifestations as well as the symptoms he was experiencing. The plan called for the patient to continue taking Lasix at the recommended dosage, as well as to incorporate atropine drops under the tongue, as well as to implement fluid restrictions and reduce the amount of salt in the diet. Atropine is a medication that is classified as an anticholinergic but has been shown to be effective in reducing fluid retention in the body. Patients suffering from congestive heart failure have also benefited from this medication. While not all of these patients require this treatment, it was effective for this patient. A year and a half later, the patient is still in hospice care and doing well. I recently spoke with him, and he is still enjoying life, having retired and working on his farm.
References
V. P. Arcangelo, A. M. Peterson, V. Wilbur, and J. A. Reinhold (Eds). (2017). A Practical Approach to Pharmacotherapeutics for Advanced Practice (4th ed.). Lippincott Williams & Wilkins, Ambler, PA.

S. N. Hilmer, A. J. McLachlan, and D. G. Le Couteur (2007). Geriatric patient clinical pharmacology. 217-230 in Fundamental and Clinical Pharmacology. [Source: https://studybounty.com/pharmacodynamics-and-pharmacokinetics-assignment]

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