Pharm responses: Pharmacokinetics and Pharmacodynamics

Pharm responses: Pharmacokinetics and Pharmacodynamics: Please respond to these 2 scenarios with 2 APA styles for each response…

Pharm responses: Pharmacokinetics and Pharmacodynamics

Post 1

Pharmacokinetics and Pharmacodynamics

Understanding Pharmacokinetics and Pharmacodynamics is crucial because medication therapy plays a crucial role in improving human health by enhancing the quality of life and extending life expectance when prescribers properly use and administer. By applying knowledge of Pharmacokinetics to drug therapy, we can help maximize beneficial effects and minimize harm (Rosenthal & Burchum 2021).

Description of the patient case from your experiences, observations, and/or clinical practice from the last 5 years.

I have witnessed and heard of many incidents of medication errors during my practice, whereby such incidents have led to extended patient hospitalization and even near-death occurrences. Many medication errors occur because nurses use medical abbreviations and lack a proper understanding of the medication dosages and frequency of administration. These abbreviations, symbols, and dose designations should never be used when communicating medical information verbally, electronically, and in handwritten applications (Ladd & Hoyt, 2016). 

An 86-year-old female patient with acute kidney injury is recovering from left hip surgery was receiving care in PACU. The anesthesiologist ordered fentanyl 50mcg intravenous every 5 mins for postop pain management. I was precepting a new nurse when I witnessed the new nurse in PACU scan 100 mcg of fentanyl and administer the full dose. Immediately upon administration, the patient lost consciousness, and the airway was obstructed; oxygen was desaturated to 72%. We had to quickly place the patient on a 10L oxygen facemask, insert a nasal trump, and do upward jaw thrusts to open the airway. It took 10 mins before the patient’s oxygen level increased and the patient regained consciousness. 

Factors that influence pharmacokinetic and pharmacodynamic processes in patients

According to Rosenthal & Burchum (2021), Pharmacokinetics studies drug movement throughout the body. As advanced nurse practitioners, it is essential to understand four basic pharmacokinetic processes: absorption, distribution, metabolism, and excretion. The purpose of Pharmacokinetics and the pharmacodynamic process is to get the current dose of the drug, at the right time to the site of action where it can produce its desired effect. Giving the wrong dose of medication to the elderly patient can cause a detrimental effect on the patient, which was the case with the scenario that I witnessed. Therefore age, gender, diet, environment, and body weight can influence the outcome of medication administration.

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Details of the personalized plan of care that you would develop based on influencing factors and patient history in your case.

In regard to medication administration, new nurses and interns have a low understanding of pharmacological implications (Myroniak & Elder, 2021). I agree with this observation because the new nurse in PACU did not understand the effects of administering 100mcg fentanyl at once, instead of the safe dose of 50mcg ordered by the anesthesiologists. Developing a plan of care to teach all new nurses in PACU about the safe administration of immediate postop analgesics and factoring in patient age. Clear communication and understanding must be established between the prescribers and those administering the medications.

Well‐prepared prescribers would be expected to make fewer prescribing errors, leading to fewer preventable adverse drug events and a reduction in delays in initiating or optimizing drug therapy (Sabatino et al., 2017). In conclusion, the detailed plan of care developed was to ensure that new nurses give no medication without demonstrating a clear understanding of the current dose, route, time, frequency, and possible side effects of the medication.


Ladd, E., & Hoyt, A. (2016). Shedding light on nurse practitioner prescribing. The Journal for Nurse Practitioners, 12(3), 166–173.

Myroniak, K., & Elder, S. (2021). Improving safe medication administration in new rns using simulation. The Journal of Continuing Education in Nursing, 52(1), 30–33.

Rosenthal, L. D., & Burchum, J. R. (2021). Lehne’s pharmacotherapeutics for advanced practice nurses and physician assistants (2nd ed.) St. Louis, MO: Elsevier.

Sabatino, J. A., Pruchnicki, M. C., Sevin, A. M., Barker, E., Green, C. G., & Porter, K. (2017). Improving prescribing practices. Journal of the American Association of Nurse Practitioners, 29(5), 248–254.

Post 2

 drug interaction is defined as an increase or decrease in the therapeutic effect of a certain drug caused by another drug, food, or supplement(May & Schindler, 2016). Drugs interact through certain mechanisms. These can include

· Pharmacokinetic interactions – influence absorption, distribution, metabolism, or excretion and increase or decrease plasma levels of a drug

· Pharmacodynamic interactions – alter the pharmacologic effect of a drug while not affecting drug plasma levels (Takeda et al., 2017).

These interactions were common with patients in the diabetic outpatient education clinic where I worked in. Many patients with diabetes suffer from comorbidities, which require treatment with multiple medications (May & Schindler, 2016). While additional medications may decrease the risk for other problems, such as heart disease, there is a higher risk of drug interactions and adverse drug effects. Metformin is the preferred medication for first-line therapy in diabetes, but the elimination rate is determined by renal function and many diabetics have some sort of kidney disease (Hsu et al., 2018). Therefore, it is essential to use caution when drugs that affect renal function are being taken at the same time.

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One particular patient in the clinic followed this path. His medical history consisted of Type II diabetes, hypertension, COPD, GERD, and gastroparesis. His medications were metformin 1500 mg, Prevacid, Reglan, amlodipine, and metoprolol. He also took several herbal supplements, such as Ginko Biloba, ginseng, flaxseed, and fish oil. After approximately six months of attending the clinic, he was diagnosed with kidney disease.


Drugs can affect pharmacokinetics by affecting absorption “due to changes in the subcutaneous adipose blood flow, muscle blood flow, and gastric emptying”(Dostalek et al., 2012, para. 1). With the patient’s stomach issues and delayed gastric emptying, there could be an altering of his gastric PH, which could affect the absorption rate of medication. Food intake and herbal supplements play a role in affecting the plasma concentration of many drugs (May & Schindler, 2016). Herbal supplements can also “interact with pharmacological medications in a different and unpredictable manner” (May & Schindler, 2016, para. 7).


Pharmacodynamics is the “study of biochemical and physiologic effects of drugs on the body and the molecular mechanisms by which those effects are produced (Rosenthal, Laura & Burchum, Jacqueline, 2020, p. 22). It is essential to control issues, such as high blood pressure and renal disease, while also controlling blood sugars. In order to do this, a combination of anti-diabetic medications may be used. When adding additional medications, hypoglycemia, weight gain, and fluid retention may occur so monitoring the patient is crucial (May & Schindler, 2016).

There are also many pharmacodynamic interactions of herbal supplements that can increase or decrease blood sugars(May & Schindler, 2016).

Plan of Care

When the patient initially began coming to the clinic, his A1C was 14% and his blood pressure was extremely high. He was adding herbal supplements to “help him feel better.” To ensure positive outcomes, it is important to “establish a medication education plan, monitor positive and negative patient responses, identify and address issues of nonadherence, and manage the patient’s complete medication regimen”(Rosenthal, Laura & Burchum, Jacqueline, 2020, p. 8).

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Education was provided regarding his disease process, his medications, and the pharmacodynamics of herbal supplements with other medications.  He discontinued the Ginko Biloba and ginseng but continued the fish oil and flaxseed because his HDL cholesterol was low at 32 mg/dl. Due to the fact that this patient did not have insurance and medication costs were a factor, metformin 1500 mg was continued. Lisinopril was added to help protect his kidneys.

Once he began to show signs of kidney disease, the metformin was decreased to 500 mg and an SGLT2 inhibitor (Jardiance) was added through a patient assistance program. SGLT2 inhibitors work by preventing the kidneys from reabsorbing glucose back into the blood(SGLT2 Inhibitors (Gliflozins), 2019). Due to the fact that metformin can accumulate in the kidneys with chronic kidney disease, the patient was monitored closely for lactic acidosis. He received lab work every three months and his kidney functions, blood sugars, and blood pressure was monitored closely. Education was provided on a weekly basis and patient assistance was provided for medication and PCP appointments to ensure his compliance.



When providing a medication education plan and monitoring the patient’s response, while addressing issues, positive outcomes can be achieved and adverse drug reactions can be minimized. This particular patient attended the clinic weekly for education and within the first year, had decreased his A1C to 7.4%.


Dostalek, M., Akhlaghi, F., & Puzanovova, M. (2012). Effect of diabetes mellitus on pharmacokinetic and pharmacodynamic properties of drugs. Clinical Pharmacokinetics51(8), 481–99.

Hsu, W.-H., Hsiao, .-J., Lin, .-C., Chen, .-C., Lee, .-Y., & Shin, S.-J. (2018). Effect of metformin on kidney function in patients with type 2 diabetes mellitus and moderate chronic kidney disease. Oncotarget9(4), 5416–5423.

May, M., & Schindler, C. (2016). Clinically and pharmacologically relevant interactions of antidiabetic drugs. Sage Journals.

Rosenthal, Laura & Burchum, Jacqueline. (2020). Lehne’s pharmacotherapeutics for advanced practice nurses and physician assistants (2nd ed.). Saunders.

SGLT2 Inhibitors (Gliflozins). (2019, January 15).

Takeda, T., Hao, M., Cheng, T., Bryant, S. H., & Wang, Y. (2017). Predicting drug-drug interactions through drug structural similarities and interaction networks incorporating pharmacokinetics and pharmacodynamics knowledge. Journal of Cheminformatics9(16).

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