Effect of Patient Factors on Pharmacokinetics and Pharmacodynamics Essay Paper

To Prepare
Review the Resources for this module and consider the impact of potential pharmacotherapeutics for cardiovascular disorders introduced in the media piece.
Review the case study assigned by your Instructor for this Assignment.
Select one the following factors: genetics, gender, ethnicity, age, or behavior factors.
Reflect on how the factor you selected might influence the patient’s pharmacokinetic and pharmacodynamic processes.
Consider how changes in the pharmacokinetic and pharmacodynamic processes might impact the patient’s recommended drug therapy.
Think about how you might improve the patient’s drug therapy plan based on the pharmacokinetic and pharmacodynamic changes. Reflect on whether you would modify the current drug treatment or provide an alternative treatment option for the patient.
By Day 7 of Week 2
Write a 2- to 3-page paper that addresses the following:

Explain how the factor you selected might influence the pharmacokinetic and pharmacodynamic processes in the patient from the case study you were assigned.
Describe how changes in the processes might impact the patient’s recommended drug therapy. Be specific and provide examples.
Explain how you might improve the patient’s drug therapy plan and explain why you would make these recommended improvements.
Reminder: The College of Nursing requires that all papers submitted include a title page, introduction, summary, and references. The College of Nursing Writing Template with Instructions provided at the Walden Writing Center offers an example of those required elements (available at https://academicguides.waldenu.edu/writingcenter/templates/general#s-lg-box-20293632). All papers submitted must use this formatting.

Effect of Patient Factors on Pharmacokinetics and Pharmacodynamics

Pharmacology and pharmacotherapeutics are disciplines concerned with the effect of drugs on the body and what the body does to the drugs once they are taken in by various routes of administration. The part of pharmacology known as pharmacokinetics is concerned with the processes that the drug undergoes once it is introduced into the body until the time that it is expelled after its half-life. Traditionally, the processes in pharmacokinetics are known by the acronym ADME. This stands for absorption, distribution, metabolism, and excretion (Rosenthal & Burchum, 2018). The other part of pharmacology is pharmacodynamics and it is about the actions of drugs on the tissues once inside the body. These two processes of pharmacokinetics and pharmacodynamics are usually impacted by a number of factors. These are age, ethnicity, gender, genetics, and behavioral factors. The simplest factor to illustrate the effects on pharmacodynamics and pharmacokinetics is age (Peeters et al., 2019). The patient in the case scenario provided is an obese adult and that means that he is definitely affected by lifestyle factors in terms of pharmacokinetics and pharmacodynamics. He is also having other lifestyle conditions related to the obesity in the form of hyperlipidemia and hypertension. These three are major risk factors for heart disease as much as they also affect the pharmacology of drugs (Hammer & McPhee, 2018). Effect of Patient Factors on Pharmacokinetics and Pharmacodynamics Essay Paper The patient is on a number of medications that are going to be used in this paper to illustrate how the factor of age affects both pharmacodynamics and pharmacokinetics. These are simvastatin, sertraline, atenolol, hydrallazine, and doxazosin. The drugs are for the management of the multiple lifestyle conditions that he suffers from. The purpose of this paper is therefore to explain how age affects pharmacokinetics and pharmacodynamics within the context of the patient in the case study.

The effect of Chronological Age on the Pharmacology of Drugs

The process of absorption of medications is less effective in infants because their gut has not fully developed. The same can be said of metabolism and excretion. Even distribution is not as effective in children as they have very little lean body mass and also adipose tissue for either hydrophilic or lipophilic medications. Their livers are not yet mature and so the cytochrome enzymes are not able to express themselves fully. Last but not least is the fact that their kidneys are still developing and cannot handle much of the toxins to be excreted. This scenario replicates in old age where the deterioration n body systems and processes also causes a similar picture in which absorption, distribution, metabolism, and excretion are affected. In the case of this patient hydrallazine in particular would be significantly affected by the first pass effect in the elderly.

When a drug exerts its mechanism of action, it is expected that the body’s defences and other mechanisms would limit this action to therapeutic levels. However, when it is a newborn or an elderly person, this action may be so pronounced that t now becomes dangerous to the patient’s safety. What will have developed in this instance is toxicity which can be life-threatening. The implication of all this is that the dose of drugs such as the ones that this patient is on must be titrated to the patient’s age and condition for optimum outcomes. For instance, since the actions of the cytochrome P450 isoenzymes and especially CYP3A4 and CYP2D6 (the most dominant in drug metabolism) are so reduced in old age, giving this patient the usual dose of hydrallazine would lead to a catastrophic drop in blood pressure within a very short time. This is assuming that the patient is an old person aged 65 years and above.

The above can even lead to death and that is why advanced practice nurses must understand the effect of age on pharmacodynamics and pharmacokinetics. The dosages of the other medications would also have to be reduced since they also undergo the first pass effect in the liver. This is the same way that inadequate excretion due to a markedly reduced glomerular filtration rate will also cause a dangerous accumulation of the active ingredient f a drug in the body. In the case of hypertension for instance, it is advisable for clinicians such as the advanced practice nurse in a full practice authority state to start the elderly hypertensive patients such as this hypothetical patient on half or even quarter of the recommended adult dose (Buelt et al., 2021; Peeters et al., 2019). The reason as has been explained above is that there are pharmacokinetic and pharmacodynamic changes in the elderly that are not comparable to a young or youthful person.

The Way Pharmacokinetic and Pharmacodynamic Changes Impact the Recommended Drug Therapy and the Patient’s Drug Therapy Plan

The consensus is that clinicians must reduce the dosages of the medications for elderly patients as for very young children. For the case patient who is presumed to be elderly, there will be an impact on the action of the drugs (such as the ineffective metabolism in the liver of hydrallazine and atenolol). Likewise, giving the usual doses means that the pharmacodynamics may be pronounced to a point that the medication will now produce toxicity to the patient. One particular drug that this patient is on is of concern. He is getting sertraline (Zoloft) as a weight loss medication. However, sertraline is also known to have the side effect of predisposing to falls. As an elderly person, the patient is already a falls risk and this may compound the problem. For this pharmacodynamic reason, the dose of the sertraline must be reduced for the patient. Only doxazosin and simvastatin do not seem to be affected much in terms of their pharmacodynamics and pharmacokinetics (Rosenthal & Burchum, 2018). For this reason they may be left at their current dosages.

Conclusion

The pharmacology of drugs is affected by a number of factors such as age, race, genes, gender, and behavioral factors. This paper has looked at age as a factor in this. Advancing age slows down bodily functions and his means that drugs can no longer be handled as safely as they used to be in youth. The end result is that the usual doses of medications have to be reduced in elderly patients.

References

Buelt, A., Richards, A., & Jones, A. (2021). Hypertension: New guidelines from the international Society of Hypertension. American Family Physician, 103(12), 763-765. https://www.aafp.org/pubs/afp/issues/2021/0615/p763.html

Hammer, D.G., & McPhee, S.J. (Eds). (2018). Pathophysiology of disease: An introduction to clinical medicine, 8^th ed. McGraw-Hill Education.

Peeters, L.E.J., Kester, M.P., Feyz, L., Van Den Bemt, P.M.L.A., Koch, B.C.P., Van Gelder, T., & Versmissen, J. (2019). Pharmacokinetic and pharmacodynamic considerations in the treatment of the elderly patient with hypertension. Expert Opinion on Drug Metabolism & Toxicology, 15(4), 1–11. https://doi.org/10.1080/17425255.2019.1588249

Rosenthal, L.D., & Burchum, J.R. (2018). Lehne’s pharmacotherapeutics for advanced practice providers. Elsevier.

Effect of Patient Factors on Pharmacokinetics and Pharmacodynamics Essay Paper