Discussion: Pharmacokinetics and Pharmacodynamics

NURS 6521 Discussion: Pharmacokinetics and Pharmacodynamics

A friend calls and asks you to prescribe a medication for her. You have this autonomy, but you don’t have your friend’s medical history. You write the prescription anyway.

Having prescriptive authority doesn’t mean it should be taken for granted. The authorization of NPs to prescribe legend and controlled medications, devices, health care services, durable medical equipment and other equipment and supplies is essential to providing timely, cost-effective, quality health care and not for our friend or family benefit (“Nurse Practitioner”, 2020).

The fact that I carried through with writing the prescription anyway makes me hope and believe that there was consideration for the friend’s medical history, allergies and possible other prescription medication or over the counter interactions. With the patient being my friend being privy to information such as being aware of any possible pharmacodynamics issues such as gender, age and ethnicity to name a few. Pharmacodynamics describes what the drug does to the body (Briscoe, 2020). Ethnicity really needs to be considered

Discussion Pharmacokinetics and Pharmacodynamics

because some medications don’t work for some people and a different drug may need to be given instead of the one requested (Walden University, n.d.).

Consideration of the friend’s renal, cardiac and other metabolic functions is necessary to prescribe the appropriate dose and frequency (Walden University, n.d.). Pharmacokinetics describes what the body does to the drug through absorption, distribution, metabolism, and excretion (Briscoe, 2020). It would not be a friendly conversation if I prescribed a medication to make my friend happy and the medication made my friend sick instead. The blame and guilt that could possibly result can cause mental health issues and eventually lead to legal ramifications (Buppart, 2018).

References

Briscoe, C. (2020). The difference between pharmacokinetics and pharmacodynamics. BioAgilytix.

https://www.bioagilytix.com/blog/2020/10/05/the-difference-between-pharmacokinetics-and-pharmacodynamics/

Buppart, C. (2018). Risks of treating family, friends and self. Law office of Carolyn Buppart.

https://cdn.ymaws.com/www.nursepractitionersoforegon.org/resource/collection/6A50A385-E0A8-424A-AFCB-2782AC455BEB/NPO-Sess215-Presentation.pdf

Nurse Practitioner Prescriptive Authority. (2020). American Association of Nurse Practitioners.

Week 1 Discussion: Main Post

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The community where I work has a large population of retired heavy drinkers. One main open heart post-surgical

cause of death is alcohol withdrawal. Alcohol withdrawal can increase a patient’s mortality by 50%. According to Wang et al. (2021), delirium developed in the inpatient setting is associated with severe consequences such as increased mortality, decreased long-term cognitive function, and increased hospital stay. Unfortunately, many individuals do not understand the severity of alcohol withdrawal, and they tend to not inform the physician of the correct amounts consumed. About a year ago, a post-surgical patient came into our unit. On his preoperative interview, he denied alcohol use with the surgeon and the anesthesiologist. The patient immediately began symptoms of withdrawal. When approaching the patient’s wife and daughter of the concerns, they denied the patient was a drinker. We insisted that they look around the house for signs of alcohol drinking they may not have been aware of. The daughter had called later that afternoon stating she had found a hidden empty bottle in the closet, behind doors, and in his office, even in his clothes hamper. Once we finally had the key to the puzzle piece, we treated the patient correctly and provided the medications needed.

If the physician had known the patient was a drinker, he would have started him on an ethanol drip, along with placing the patient on the CIWA protocol to keep his withdrawal at bay. Our CIWA protocol includes a scale to provide Librium and Ativan when needed. According to Rosenthal and Burchum (2021), the management of withdrawal depends on the degree of dependence. According to Ahwazi & Abdijadid (2020), it is metabolized by the liver microsomal pathway, first by hepatic oxidation, then by glucuronidation. The elimination half-life of this medication is 24 to 48 hours, and its excretion is via the urine. Librium and Ativan decrease withdrawal symptoms, stabilize vital signs, and assist in preventing seizures and DT’s.

When creating a personal plan for a patient, incorporating current medications, living style, including smoking and alcohol, must be considered. For this patient, the plan would have included starting on benzodiazepines before the surgery, out on the unit where the patient was receiving preop testing, along with adding a low dose ethanol gtt. drip after surgery.

Reference

Ahwazi, H. H., & Abdijadid, S. (2020, November 22). Chlordiazepoxide. Retrieved from https://www.ncbi.nlm.nih.gov/books/NBK547659/

Rosenthal, L. D., & Burchum, J. R. (2021). Lehnes pharmacotherapeutics for advanced practice nurses and physician assistants. St. Louis, MO: Elsevier.

Wang, A., Park, A., Albert, R., Barriga, A., Goodrich, L., Nguyen, B., . . . Preda, A. (2021). Iatrogenic Delirium in Patients on Symptom-Triggered Alcohol Withdrawal Protocol: A Case Series. Cureus. doi:10.7759/cureus.15373

Week 1 Discussion

COLLAPSE

Taking care of a covid patient can be very challenging at times. A scenario for patient care was a 76-year female that was fully vaccinated that tested positive for Covid 19. ABG’s were drawn and Po2 was 57%, the patient was very confused due to lack of oxygenation; the patient quickly was started on Hi Flo oxygen with FIo2 100%. Her oxygen saturation on the monitor was showing 85% so a nonrebreather mask was applied along with Hi-flo oxygen. The patient needed to be placed on bipap but could not be because of the agitation and the risk of pulling the mask off. The patient was placed on Precedex drip to help with relaxation and sedation. The precedex drip was titrated per order. After a couple of hours, the drip was titrated down because the patient’s heart rate started dropping down in the lower 50’s. The patient had history of COPD, HTN, and diabetes II. A repeat ABG was done hours later and showed that the patients pO2 was now 43.6%. The provider called the family to see if they wanted the patient to be intubated or made comfort care, because the chances of a Covid patient coming off the vent are very slim. The son and husband decided to go with the patient being placed on the ventilator. The patient was given succinylcholine and etomidate IV push for the intubation and then started on a propofol and fentanyl drip. The liver metabolizes both propofol and fentanyl. The propofol is used for a sedative and the fentanyl is used for pain. The precedex was stopped and mitts was placed to both BUE to prevent self extubation. The patient’s vital signs remained stable and her 02 sats maintained above 95%. The propofol can cause an increased in the patients triglycerides so that specific lab has to be checked every 72 hours.

Neonatal abstinence syndrome (NAS) occurs when newborns are born to drug-addicted mothers. This can cause drug withdrawal that can be observed in the newborn around the 3-5 days post birth (Sinha et al., 2018). The symptoms of NAS include hypertonia, high pitched cry, tremors (sometimes seizures) and irritability along with sneezing, diarrhea, vomiting, sweating, yawning and poor feeding (Sinha et al., 2018, pp. 265). These symptoms are imputed into a Finnegan Scale which allocates each symptom and creates a score to help treat and manage the neonate (Sinha et al., 2018, pp. 30). Treatments of NAS include oral morphine, phenobarbitone or clonidine may also be added to help with treatment. Influences by pharmacokinetics as far as absorption rates vary with oral administration and is more reliable with subcutaneous/ intravenous administration (Vallerand et al., 2015). Half life for neonates is about 7 hours and for infants ages 1-3 months is about 6 hours (Vallerand et al., 2015).

Patient scenario involved a newborn 38 and 2/7 week old female patient born via c-section for non reassuring fetal heart tones. Mother of the patient has a history of opiates and amphetamine abuse. Patients demonstrated increased agitation even after non-pharmacological treatment was utilized such as decreased stimulation, bundling, and holding. Patient symptoms included increased agitation with a high pitched cry, tremors, diaphoresis, and emesis post feeds. Upon admission meconium drug screen was obtained and sent. Due to the mother’s positive drug screen from the birth hospital and the patient’s two high Finnegan scores (greater than 12), oral morphine was started. NAS due to opiates occurs in about 55-94% of newborns with in utero narcotics exposure (Johnson et al., 2003). the symptoms can be present but can manifest at 10-14 days of life and can last up to 6-8 months after birth (Johnson et al., 2003).

Non pharmacologic treatment would be the recommended start of treatment and after two Finnegan scores that are greater than 12 pharmacological treatment is recommended (Sinha et al., 2018). Due to the two Finnegan scores that were greater than 12, treatment was started. Every 8 hours reassessment of treatment plan is needed if Finnegan scores are still high, increasing the dose by 20% or by facility protocols until symptoms are controlled is recommended (Sinha et al., 2018). Same recommendations are given when weaning from the drug and close monitoring of drug withdrawal should be observed. Other treatment involved for the patient includes monitoring of feeding, growing and sleeping habits which are attained with decreasing environmental stimuli. Frequent small feeds for the patient is necessary to reduce the chance of emesis and maintaining a fluid goal of at least 150 ml/kilogram/day is needed.

Resources

Johnson, R. E., Jones, H. E., & Fischer, G. (2003). Use of buprenorphine in pregnancy: patient

management and effects on the neonate. Drug and alcohol dependence, 70(2 Suppl), S87–S101. https://doi.org/10.1016/s0376-8716(03)00062-0

Sinha, S., Miall, L., & Jardine, L. (2018). Essential neonatal medicine (6th ed., pp. 30, 31,

265). Hoboken: John Wiley & Sons Inc.

Vallerand, A. H., Sanoski, C. A., Deglin, J. H., & Rodenberger, J. (2015). Davis’s drug guide for

nurses (Fourteenth edition.). F. A. Davis Company.

As a nurse in the psychiatric field, medication is a critical component of the patient’s holistic treatment. Medication is necessary for restoring the patient to their baseline as much as possible, therefore a great emphasis is placed on medication compliance as well as achieving a therapeutic dose that not only treats the patient’s symptoms, but allows them to function as independently as possible. Additionally, any medical diagnoses, medical medication, or additional psychiatric medications are at risk for interacting negatively with each other. For example, many psychiatric medications can raise blood sugar and cause weight gain, which causes complications for patients with diabetes that require a medication change or a dose that may not be as effective. With this in mind, pharmacokinetics and pharmacodynamics processes play a critical role in finding the best course of treatment for the patient.

The patient case that comes to mind involves a female patient in her mid 40’s who was diagnosed with bipolar disorder. Her stay on the unit I was working on at the time lasted from 2020 to early this year. The patient had severe episodes of mania in which she had verbal and physical aggressive behavior that required excessive medication treatment. Finding the therapeutic range for this patient’s medication was challenging because high doses would cause excessive lethargy, while lower doses would not treat her symptoms. Rosenthal (2021) explains that understanding the therapeutic range of medication is important for the safe administration of drugs. This aspect of pharmacokinetics dictates the dose that the psychiatrist can safely prescribe to the patient, and must be considered first and foremost. The medical issues that the patient experienced included chronic constipation and frequent episodes of loose and watery stools. Psychiatric medication can mimic gastrointestinal disorders by causing similar symptoms, and this information is frequently considered in any patients’ plan of care (Philpott et al., 2014). The patient required frequent enemies and laxatives, although treatment was not always effective. Although her constipation and episodes of loose and watery stools were later attributed to a cause other than medication, her medication doses were changed frequently during the first part of her stay in order to decrease her medical symptoms.

Common psychotropic medications often have side effects that include diarrhea, and antipsychotics (which the patient was on) can cause constipation (NIMH, 2016). When considering the best plan of care to develop for my patient, her response to the medication as well as the interactions it has with her health would be the most important factors. The initiative plan of action would be to assess the patient’s history with gastrointestinal issues (it was later revealed the patient had previously experienced bloating and constipation due to a hernia, similar to what she was displaying in the hospital). The interaction between psychotropics and the medication she is on for constipation also needs to be considered. The patient should be consulted for her input on treatment effectiveness (i.e. if she feels like her psychiatric symptoms are improving without negatively impacting her physical health or quality of life).

Overall, restoring the patient to an independent level of function (or as independent as possible) without decreasing her quality of life is the end goal. This will be achieved through collaboration between psychiatric and medical providers, as well as input from the patient. Communicating treatment goals and rationales to the patient is key. Additionally, the impact that pharmacokinetics and pharmacodynamics have on holistic care should always be taken into consideration.

References:

U.S. Department of Health and Human Services. (2016, October). Mental health medications. National Institute of Mental Health. Retrieved December 2, 2021, from https://www.nimh.nih.gov/health/topics/mental-health-medications.

Philpott, H. L., Nandurkar, S., Lubel, J., & Gibson, P. R. (2014). Drug-induced gastrointestinal disorders. Frontline gastroenterology, 5(1), 49–57. https://doi.org/10.1136/flgastro-2013-100316

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

Basic Pharmacotherapeutic Concepts/Ethical and Legal Aspects of Prescribing

COLLAPSE

Case Study

A 35 year old women reported with an HbA1c level of 12% with no previous diagnosis of DM. Her last pregnancy was at the age of 30 when she was informed of slightly high levels random blood glucose but was not required to take any medication during or post pregnancy. The patient was alarmed by her values. She was started on oral hypoglycemic. Her lab values were repeated in 3 months and her HbA1c dropped to 6%. This drastic change in her lab values were resultant of her proactive approach to change her lifestyle and assume responsibility for her health alongside the medication regimen. On further enquiry she stated to have used fenugreek as advised by her mother. Her compliance with diet, exercise and medication caused a significant change in her lab values. She continued to maintain her adherence to the renewed lifestyle and for the last 5 years has not required any further medications.

Pharmacokinetics and Pharmacodynamics

While pharmacokinetics may be defined as the movement of drugs through the body (absorption, distribution, metabolism and excretion), the process of pharmacodynamics involves the body’s biological response to drugs (receptor binding, post receptor effect and chemical interactions).

It is reported that concomitant administration of fenugreek extract with certain hypoglycemic agents maintains lower blood glucose levels than medication alone. In a study conducted by the pharmacokinetic study showed that concurrent administration of fenugreek significantly increased the bioavailability of metformin and doubled the time required to reach the peak plasma concentration (Abdelwahab et al., 2021).

Natural remedies such as the use of fenugreek mediate enhancement of glucose uptake and suppression of hepatic glucose output by stimulating glycolysis, glucose oxidation and glycogenesis, along with reducing glycogen degradation and gluconeogenesis (D’souza, 2021).

Personalized plan of care

The patient did show significant improvement in her lab values. Her commitment to medication regimen and her diet and lifestyle changes, all contributed effectively to her health care plan. Continuing to motivate her in her compliance and keeping her abreast with the latest information in the management of her condition will facilitate her adherence to her overall health.

References

Abdelwahab, N. S., Morsi, A., Ahmed, Y. M., Hassan, H. M., & AboulMagd, A. M. (2021). Ecological HPLC method for analyzing an antidiabetic drug in real rat plasma samples and studying the effects of concurrently administered fenugreek extract on its pharmacokinetics. RSC Advances, 11(8), 4740-4750.

D’souza, M. R. (2021). Traditional Indian Herbs for the Management of Diabetes Mellitus and their Herb–Drug Interaction Potentials: An Evidence-Based Review. Structure and Health Effects of Natural Products on Diabetes Mellitus, 279-296.

Pharmacokinetics and pharmacodynamics are important when managing the health of patients. Pharmacokinetics is defined as the study of drug movement throughout the body (Rosenthal and Burchum, 2021). It consists of four processes including absorption, distribution, metabolism, and excretion. These processes can have an effect on the therapeutic management of drug therapy in patients. Pharmacodynamics is the study of biochemical and physiologic effects on the body and the molecular mechanisms by which these effects are produced (Rosenthal and Burchum, 2021). The results of these effects are based on the time and intensity of the therapeutic effects, as well as the occurrence of adverse drug reactions. There are several factors that can influence the pharmacokinetics and pharmacodynamic processes, including age, gender, ethnicity, behavior, genetics, and disease processes. It is important for the health care provider to have an understanding of pharmacokinetics and pharmacodynamics and its influence on drug therapy in order to develop an effective the plan of care for patients.

One previously worked as a home care nurse and took care of K.S. in her home. K.S. is a 70-year-old, African American female who was recently discharged from the hospital after undergoing a tricuspid valve repair. K.S. medical history includes right-sided heart failure, hypertension, hepatitis C, and ascites of the liver. K.S. was diagnosed post-surgery with chronic kidney disease, hypotension, and atrial fibrillation. K.S. discharge instructions were to include continuing taking previous medications prescribed along with midodrine and warfarin. K.S. was unsure of why she was taking certain medications, if and when her blood pressure should be checked, blood pressure parameters when taking midodrine and other prescribed hypertensive medications, the daily of dosage of warfarin and when laboratory testing needed to be completed to check PT/INR. K.S. observed to be frail in statue and was ordered Ensure three times per day.

Age along with pathophysiologic changes related to disease are huge factors that can affect pharmacokinetics and pharmacodynamic processes. According to Rodrigues, Herdeiro, Figueiras, Coutinho, and Roque (2020), ageing is a process that inevitable resulting in a decline in functioning and increased susceptibility to certain diseases, requiring the use of an increased amount of medication. Ageing can affect the distribution, metabolism, and excretion in the process of pharmacokinetics. Changes in body mass and protein synthesis can affect distribution of a drug and nutritional status can affect the rate of metabolism of a drug in an ageing patient (Rodrigues et. al, 2020). Most drugs are eliminated through kidneys. In the ageing patient, there is a decline in renal function related to a decrease in the glomerular filtration rate and renal blood flow, which makes it difficult for drugs to be excreted through the kidneys. This, in turn, puts the patient at risk for adverse drug reactions. According to Ponticelli, Sala, and Glassock (2015), older patients who have kidney disease are most at risk for adverse drug reactions. The process of pharmacodynamics affected by ageing can cause drug sensitivity and impaired homeostasis.

The patient K.S. has several medical conditions, resulting in a numerous amount of prescribed medications. She is frail in statue and has a lean body mass, which can affect the distribution of the medications prescribed. She, also, has poor nutritional status, which can affect the metabolism of the medications prescribed. She has been recently diagnosed with chronic kidney disease, which can affect elimination of the medications prescribed. She is prescribed warfarin, in which the response can be increased due to drug sensitivity leading to an adverse event. Also, due to impaired homeostasis, blood pressure regulation could be affected.

In developing a personalized plan of care for patient K.S., one has to take into consideration the patient’s age and medical history. One would review the drug therapy with the patient and discontinue any medications that are not necessary, have drug interactions, or put the patient at risk for an adverse drug reaction. One would ensure that current laboratory testing has been completed and review the laboratory results with the patient. Based on these results, one would consider medications that are safer for the patient and has the lowest effective dose possible. One would provide education to the patient on disease processes, purpose of medications prescribed, checking blood pressure and parameters to follow. One would stress the adherence to medication regimen and the importance of laboratory testing.

References

Ponticelli, C., Sala, G., and Glassock, R. (2015). Drug management in the elderly adult with

chronic kidney disease: a review for the primary care physician. Mayo Clinic Proc., 90

(5). Doi.org/10.1016/j.mayocp.2015.01.016.

Rodrigues, D., Herdeiro, M., Coutinho, P., and Roque, F. (2020). Elderly and polypharmacy:

physiological and cognitive changes. Frailty in the Elderly.

Doi:10.5772/intecopen.92122.

Rosenthal, L.D. and Burchum, J.R. (2021). Lehne’s pharmacotherapeutics for advanced practice

nurses and physician assistants (2^nd ed.). St. Louis, MO: Elsevier.

Pharmacokinetics and Pharmacodynamics

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.

Resources

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

WEEKLY 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.

By Day 3 of Week 1

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.

By Day 6 of Week 1

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.

Note: For this Discussion, you are required to complete your initial post before you will be able to view and respond to your colleagues’ postings. Begin by clicking on the Reply button to complete your initial post. Remember, once you click on Post Reply, you cannot delete or edit your own posts and you cannot post anonymously. Please check your post carefully before clicking on Post Reply!