As an advanced practice nurse assisting physicians in the diagnosis and treatment of disorders, it is important to not only understand the impact of disorders on the body, but also the impact of drug treatments on the body. The relationships between drugs and the body can be described by pharmacokinetics and pharmacodynamics. 

Pharmacokinetics describes what the body does to the drug through absorption, distribution, metabolism, and excretion, whereas pharmacodynamics describes what the drug does to the body. 

When selecting drugs and determining dosages for patients, it is essential to consider individual patient factors that might impact the patient’s pharmacokinetic and pharmacodynamic processes. These patient factors include genetics, gender, ethnicity, age, behavior (i.e., diet, nutrition, smoking, alcohol, illicit drug abuse), and/or pathophysiological changes due to disease. 

For this Discussion, you reflect on a case from your past clinical experiences and consider how a patient’s pharmacokinetic and pharmacodynamic processes may alter his or her response to a drug. 



Be sure to review the Learning Resources before completing this activity.
Click the weekly resources link to access the resources.  


To prepare: 

  • Review the Resources for this module and consider the principles of pharmacokinetics and pharmacodynamics. 
  • Reflect on your experiences, observations, and/or clinical practices from the last 5 years and think about how pharmacokinetic and pharmacodynamic factors altered his or her anticipated response to a drug. 
  • Consider factors that might have influenced the patient’s pharmacokinetic and pharmacodynamic processes, such as genetics (including pharmacogenetics), gender, ethnicity, age, behavior, and/or possible pathophysiological changes due to disease. 
  • Think about a personalized plan of care based on these influencing factors and patient history in your case study. 


Post a description of the patient case from your experiences, observations, and/or clinical practice from the last 5 years. Then, describe factors that might have influenced pharmacokinetic and pharmacodynamic processes of the patient you identified. Finally, explain details of the personalized plan of care that you would develop based on influencing factors and patient history in your case. Be specific and provide examples. 


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. 



As a Med-Sure nurse for the past 2 1/2 years I’ve been a nurse, I’ve seen how medications can help or make a patient’s condition worse depending on how they react to it. There are medications that patient may be allergic to which can be deadly. “Absorption is the drug’s movement from its site of administration into the blood.” (Rosenthal & Burchum, 2021, p.13). Pharmacokinetics and pharmacodynamics work hand in hand so we can understand how the drug work, how we can safely administer them, and their effects.  Pharmacokinetics and pharmacodynamics work hand in hand together when administered in the body. It is the way we as providers can help understand the mechanism of how it works for us to write the proper correct prescriptions for patients. There are many variations in drug responses. A few to mention are race, age, gender, genetics and tolerance. 

   Reflecting on a past time encounter with a patient last month, he had numerous episodes of bloody stools, so many times that I’ve given him about 4 blood transfusions within three weeks span. He has been newly diagnosed with Parkinson’s disease and has had a spinal fusion which typically made him uncomfortable in bed, having to find the best position for him while resting in bed. For pain Oxycodone 5 mg has been ordered for him. As the team who was following him talk talked to him by updating his condition and plan of care, he was told that maybe the oxycodone may be the cause or one of the cause for his bleeding. He did have a few colonoscopies done which showed ulcers. Now with any mediation taken long term can result in addiction, resistance, worsening responses, and death. According to Memorial Sloan Kettering Center, the drug may cause or worsen stomach ulcers and bleeding.  


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

Oxycodone and Ibuprofen. Memorial Sloan Kettering Cancer Center. (n.d.). Retrieved November 27, 2022, from 



As a nurse for 3 years, I have taken care of patients with a variety of disorders and illnesses. When determining the best treatment for patients, pharmacokinetics, or how the body processes the drug as well as how it interacts within the body is critical. “That is, when two drugs are taken together, one may alter the absorption, distribution, metabolism, or excretion of the other.” (Rosenthal & Burchum, 2021). When I used to work as a bedside Med/Surg Nurse I remember taking care of a patient with Post-op Knee Arthroplasty, with Chronic Kidney Disease (CKD) who was on hemodialysis. It was crucial to make sure what medicines you are giving patients when their kidneys are not functioning properly and may cause further damage due to lack of systemic clearance, build-up of toxins, and lack of metabolism. For a post-op surgical patient pain medications were very important to control the patient’s pain. Blood pressure monitoring is important with CKD patients as pain also increases blood pressure. Hemodialysis also tends to cause cramping and pain.

The patient was in excruciating pain post-op surgery and was scheduled for hemodialysis the next day, morphine 1mg was ordered as needed and oxycodone 5mg. Morphine 1mg was given as per the pain scale. “Morphine and codeine are not recommended, because the accumulation of their metabolites may cause neurotoxic symptoms” (Coluzzi et al., 2020) Moreover, elder patients have pharmacodynamic sensitivity compared with younger adults. Hence, constant monitoring was needed to make sure the patient blood pressure, respiration, and other vitals are stable.  I educated the patient as his pain subsided a bit on tramadol that was ordered because getting morphine every time is not good for him or his kidneys. Controlling pain with Opioids post-op can heavily affect patients with chronic kidney disease as the metabolites accumulate and increase the risk of toxicity. The glomerular filtration rate (GFR) needs careful monitoring. 

Due to the patient’s history and recent surgery, it was crucial to not only control the pain but also anticipate it. It was also important to prescribe medications that would be less harmful to the kidneys and also take the age into the consideration. Tylenol IV around the clock would have been slightly beneficial so the patient would not have been in excruciating pain post-surgery. Tylenol tends to be less harmful to the kidneys and is the choice of drug for CKD patients. IV route would have enhanced the relief a lot faster. Taking morphine, not only negatively affects the kidney but also causes drowsiness and respiratory distress. It is also only effective for a short amount of time. Oxycodone 5mg would have helped but a higher dose would have helped with such unbearable pain. Older patients tend to excrete and metabolize a lot slower than younger patients, hence having oxycodone 10mg and Tylenol 1000mg around the clock for the first day after surgery would have been more beneficial than morphine as a needed dose. I would also add non-pharmacological interventions Tylenol IV would be beneficial for the patient.   


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

 Coluzzi, F., Caputi, F. F., Billeci, D., Pastore, A. L., Candeletti, S., Rocco, M., & Romualdi, P. (2020, September 9). Safe use of opioids in chronic kidney disease and hemodialysis patients: Tips and tricks for non-pain specialists. Therapeutics and clinical risk management. Retrieved November 28, 2022, from 



Patient Scenario

Jane Doe is a 32-year-old G4P4 who vaginally delivered a viable female infant at 0804 this morning. Two hours post-delivery the patient comes over to the postpartum unit, and report is obtained from the labor & delivery (L&D) nurse. This same nurse attended her delivery and cared for her throughout her recovery. She reported that the patient had an uncomplicated delivery, infant weighed 3573 grams, a first-degree perineal laceration was noted and repaired, her quantitative blood loss was 250 milliliters. The patient has an 18 gauge IV in her left hand. Her fundus is noted to be firm, midline, and at the level of the umbilicus. The patient is planning to breastfeed her infant. The L&D nurse states that the patient attempted but was unable to void after the delivery prior to transferring to postpartum. The patient denies any pain currently. Jane Doe had an adequate and uncomplicated course of prenatal care. Her medical history includes gestational hypertension for which she has been taking Labetalol 200mg twice daily during her pregnancy, lupus, anxiety, and depression. She is unmedicated for the latter diagnoses.

Her blood pressures have been closely monitored and have been under control in the 130s/70s-80s throughout her pregnancy. She does admit to smoking 1/2 pack per day for the last 15 years but has no history of drinking alcohol. Her BMI is within normal range, and she has no family history of hypertension. Her vital signs upon admission to postpartum are T:98.3, P:110, BP:165/93, RR:20, SpO2:99% on room air. The patient’s vital signs were stable during her labor, delivery, and recovery with only slightly elevated blood pressure but nothing of concern. The patient’s lab work and urinalysis that was obtained prior to delivery was all within normal limits. Jane Doe is given her morning dose of Labetalol 200mg at the time of admission. The nurse will reassess her blood pressure 1 hour after administration and report to the doctor.

Factors Influencing Pharmacokinetics

The antihypertensive drug Labetalol is an alpha-beta blocker. Its use is recommended for treating gestational hypertension as it is safe for pregnant women and their unborn child. It is also safe for breastfeeding mothers. Labetalol relaxes blood vessels leading to a decrease in blood pressure and heart rate (Khan, 2020). The extent of decrease in blood pressure depends on the route of administration of Labetalol. In oral administration, a drop in blood pressure can be seen 20 minutes to 1 hour after administration, while effects from IV administration can be seen in just minutes. Labetalol is absorbed rapidly via first pass metabolism into the blood plasm through the liver or gastrointestinal tract. The highest concentration levels are seen at around 1-2 hours post administration. Labetalol’s half-life is approximately 3-3.5 hours after administration. The bioavailability is shown to correlate with the age of the patient with values of only 30% seen in patients aged 30-40. My patient falls in this age range at 32 years old. The bioavailability is noted at higher levels in older patients doubling to 60% at the age of 80. This percentage is also noted to increase when the medication is taken with food. The liver is responsible for excretion of Labetalol. After a dose of Labetalol is administered to a patient, the hepatic system rids the blood stream of approximately 85% of the medication. Excretion of Labetalol is dependent on the quality of hepatic blood flow. Labetalol is metabolized through conjugation to glucuronide metabolites and is excreted via urine and bile in feces (Abdullah & Yusof, 2019).

Factors Influencing Pharmacodynamics

Labetalol is a dual action medication. It is both an alpha1-adrenergic antagonist and a beta-adrenergic antagonist. Labetalol selectively antagonizes alpha1-adrenergic receptors and non-selectively antagonizes beta-adrenergic receptors, therefore the activity ratio of alpha to beta blockage when administered via the oral route is 1 to 3. When administering via the intravenous route the ratio is 1 to 7 (Miller et al., 2022). When Labetalol is administered, alpha1-adrenergic antagonism occurs which lowers blood pressure by vasodilation and a decrease in vascular resistance. Continued vasodilation from Labetalol use will not decrease stroke volume or cardiac output. Beta-adrenergic antagonism causes a decrease in the patient’s heart rate. Labetalol stops adrenergic stimulation of β-receptors in the smooth muscles, cardiac muscles, and bronchial muscles. This blockade is what causes a decrease in systemic blood pressure. This process also elicits some of the side effects caused by Labetalol such as bronchospasms. For this reason, Labetalol is contraindicated in patients with asthma (Abdullah & Yusof, 2019).

Personalized Plan of Care

The plan moving forward for Jane Doe was to recheck her blood pressure 1 hour after administration of Labetalol 200mg. Her blood pressure remained elevated at 160/99. I notified the provider who increased her Labetalol dose to 300mg three times daily. At this time, I administered the extra dose of 100mg of Labetalol to equal the newly ordered dosage, and her blood pressure was rechecked again in 1 hour. The patient’s blood pressure did respond to the extra dose of Labetalol, and her blood pressure dropped to 135/80. Increasing the strength and frequency of the medication kept the concentration levels in her body at a higher percentage throughout the day to control her blood pressure. Going forward, her blood pressures were checked every four hours or more frequently as needed throughout her stay. The nurses on each shift assessed for edema, changes in vision, and daily weight checks were performed. Gestational hypertension is high blood pressure that develops after 20 weeks gestation, and it usually subsides after delivery of the infant. In this patient’s case, the blood pressure did not immediately return to normal range.

She will likely have to remain on the Labetalol for the next couple weeks. She will follow up in the office with her OBGYN in 1 week for a blood pressure check. There are a few factors that could have caused this. The patient could have an overabundance of fluid onboard from receiving intravenous fluids before, during, and after her delivery. The patient also has a history of lupus which puts her at greater risk for gestational hypertension. Gestational hypertension also makes this patient more susceptible for developing chronic hypertension later in life. The patient’s history of smoking for the past 15 years is a major factor that can contribute to hypertension. I educated her on smoking cessation. If this patient’s blood pressure had not decreased our next plan of action would have been to transfer her back to Labor & Delivery and begin a magnesium drip to control her blood pressure. This is recommended for emergency treatment to reduce the risk of preeclampsia induced seizures (Morgan, 2021).


Abdullah, A., & Yusof, M. (2019). Labetalol: A brief current review. Pharmacophore.

Links to an external site.

Gestational hypertension: Causes, symptoms & treatment. (2022). Cleveland Clinic.

Links to an external site.

Hypertension during pregnancy and after delivery: Management, cardiovascular outcomes and future directions. (2018, September 28). American College of Cardiology.

Links to an external site.

Khan, A. (2020, April 10). Taking Labetalol in pregnancy: Is it safe, risks & side effects. FirstCry Parenting.

Links to an external site.

Miller, M., Kerndt, C. C., & Maani, C. V. (2022, July 12). Labetalol – StatPearls – NCBI bookshelf. National Center for Biotechnology Information.

Links to an external site.

Morgan, J. (2021, February 23). Postpartum hypertension: When a new mom’s blood pressure is too high | Heart | Your pregnancy matters | UT southwestern Medical Center. UT Southwestern Medical Center | The #1 Best Hospital in DFW.