NURS 6521 Week 1 Discussion: Pharmacokinetics and Pharmacodynamics
Example 3
The patient case that I recall from my past experiences is about a 40-year-old male patient who was admitted following an amputation. The patient transferred to rehab just days after the surgery and was not medically stable to endure 3 hours of therapy. Some comorbidities include a kidney transplant, ESRD on peritoneal dialysis, hypertension, and diabetes. The patient was chronically hypotensive, with normal systolic blood pressures in the 80s. Current medications included anti-hypertensives and alpha-adrenergic agonists. During therapy, the patient would experience orthostatic hypotension dropping down to the 60’s.
Some factors might have influenced pharmacokinetic and pharmacodynamic processes in this patient. Pharmacokinetics involves absorption, distribution, metabolism and excretion. After the medication is ingested, it gets absorbed into the bloodstream, which moves from the blood into the cell.
The drug is then metabolized by the liver and excreted primarily by the kidneys. Drugs and their metabolites can exit the body in urine, bile, sweat, saliva, breast milk, and expired air (Rosenthal, 2021). Patients with chronic kidney disease will respond to drugs differently than patients with normal kidney function. In patients with healthy kidneys, small molecules and drugs get filtered through the glomerulus. In the tubules, lipid-soluble drugs undergo passive reabsorption. Lastly, active transport systems can pump drugs into the tubule to be excreted with urine.
For patients who have ESRD, the excretion of drugs is affected tremendously. Whether kidney disease is acute or chronic, drug clearance decreases, and the volume of distribution may remain unchanged or increase” (Roberts, et.al., 2018). Duration and intensity are factors to consider in these patients due to the increased number of free drugs in the blood. With patients who are taking multiple drugs, there is a delayed excretion of drugs if they use the same transport system, and the medication effects can be delayed. According to Sommer, Seeling, and Rupprecht, “70.4% of the residents with an estimated glomerular filtration rate (eGFR) < 60 mL/min take at least five drugs, with 17.7% of them taking > 10 drugs as long-term medication” (2020).
The personalized care plan that I would implement for this patient included taking a full history of medications including herbal and over-the-counter drugs. Accurate documentation of medications prevents adverse drug-to-drug interactions, medication replication, and dosage errors. As the provider, we can adjust the dosage of medications accordingly. In the case of this patient, a decrease in the dosage of antihypertensive medications should be considered because the patient continues to have hypotension.
Renal dosage of these medications also must be taken into consideration, are these medications appropriate for patients with chronic kidney disease? I would monitor for signs and symptoms of toxicity including low blood pressure, dizziness, headaches, and feeling tired. Monitor blood pressure throughout the day, especially before and after taking blood pressure medications and when the patient reports symptoms of hypotension. The patient would benefit from education about the medications and what signs and symptoms to monitor for.
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