NURS 6521: Advanced Pharmacology Full Class

NURS 6521: Advanced Pharmacology Full Class

Patient Case and History

Atrial fibrillation is more prevalent in males than females (Ko et al., 2016). In my clinical experience, I encounter patients with A-fib, both male and female. Recently, an 83-year-old male patient presented with Atrial Fibrillation, rapid ventricular response in the 160’s, hypotension, and acute kidney injury. The patient had retained 800cc of urine in the bladder, necessitating the placement of a foley catheter. He had a medical history of hypertension, congestive heart failure, BPH, coronary artery disease, and hyperlipidemia. His heart conditions and CAD history predispose him to arrhythmias like A-Fib. Elevated heart rate complications are especially significant in older patients, given their reduced cardiac reserve compared to younger individuals.

Pharmacodynamics and Pharmacokinetics

Amiodarone stands as the most effective antiarrhythmic for converting atrial fibrillation to sinus rhythm. However, its use in the United States is typically reserved as a last resort due to potential complications like neurotoxicity, hepatitis, thyroid issues, and pulmonary fibrosis (Chokesuwattanaskul et al., 2020). In this patient’s case, he presented in the ED during atrial fibrillation onset, making the timing uncertain.

Considering amiodarone isn’t viable at this stage, I recommended digoxin as the next treatment option. Given the patient’s hypotension and history of CHF, I chose digoxin as it can lower heart rate without significantly affecting blood pressure. Digoxin undergoes liver metabolism and kidney excretion, primarily as unchanged drug in urine (Stopfer et al., 2016). The patient had normal liver function, but an acute kidney injury (AKI) posed a challenge. The AKI was influenced by urinary retention caused by BPH. Post-foley catheter insertion, the urinary flow improved, subsequently correcting the AKI.

Plan of Care

After thorough assessment, the cardiologist approved administering digoxin. Typically, low blood pressure is addressed before CHF treatment. The patient received a continuous fluid infusion at 125ml/hour to avoid fluid overload. To manage afib with RVR, I suggested a loading dose of intravenous digoxin at 8mcg/kg. This dose was split in two, with the second half divided into halves and administered every 8 hours for two doses. This dosing approach allows monitoring for toxicity in the event of impaired kidney function. Upon heart rate control, the plan shifts to oral digoxin for daily maintenance. Upon discharge, the cardiologist will assess the digoxin dose’s effectiveness and drug levels in the body for potential dose adjustment.

References 

Chokesuwattanaskul, R., Shah, N., Chokesuwattanaskul, S., Liu, Z., & Thakur, R. (2020). Low-dose Amiodarone Is Safe: A Systematic Review and Meta-analysis. The Journal of innovations in cardiac rhythm management, 11(4), 4054–4061. https://doi.org/10.19102/icrm.2020.110403

Ko, D., Rahman, F., Schnabel, R. B., Yin, X., Benjamin, E. J., & Christophersen, I. E. (2016). Atrial fibrillation in women: epidemiology, pathophysiology, presentation, and prognosis. Nature reviews. Cardiology, 13(6), 321–332. https://doi.org/10.1038/nrcardio.2016.45

Stopfer, P., Giessmann, T., Hohl, K., Sharma, A., Ishiguro, N., Taub, M. E., Zimdahl-Gelling, H., Gansser, D., Wein, M., Ebner, T., & Müller, F. (2016). Pharmacokinetic Evaluation of a Drug Transporter Cocktail Consisting of Digoxin, Furosemide, Metformin, and Rosuvastatin. Clinical pharmacology and therapeutics, 100(3), 259–267. https://doi.org/10.1002/cpt.406

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NURS 6521: Advanced Pharmacology Full Class
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Patient Case and History

Atrial fibrillation is more common in males than females (Ko et al., 2016). With that being said, I frequently see patients in A-fib, both men and women. For this case, I had an 83-year-old, male patient present with Atrial Fibrillation with rapid ventricular response in the 160’s, hypotension, and an acute kidney injury. The patient was found to be retaining 800cc of urine in the bladder upon arrival and a foley was placed. The patient had a history of hypertension, congestive heart failure, BPH, coronary artery disease, and hyperlipidemia. The patient’s heart conditions and CAD predisposition him to develop an arrhythmia, such as A-Fib. An elevated heart rate can cause complications in any patient, but especially in older patients. The workload that an elderly heart can handle is significantly less than that of a young, healthy heart. Therefore, it is important to quickly address the elevated heart rate of an 83-year-old man NURS 6521: Advanced Pharmacology Full Class.

Pharmacodynamics and Pharmacokinetics

Amiodarone is considered the most effective antiarrhythmic medication for conversion of atrial fibrillation to sinus rhythm. In the United States, we utilize amio as a last resort unless we know the exact time that the patient went into the arrhythmia, amiodarone can cause neurotoxicity, hepatitis, thyroid complications, and pulmonary fibrosis (Chokesuwattanaskul et al., 2020). For this patient, he presented in the emergency department in atrial fibrillation so we cannot be sure of the time of conversion.
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Since amiodarone is not an option at this point in the patients plan of care, my suggestion for the next line of defense was digoxin. Since the patient is hypotensive and we prefer to not bolus him with fluids due to the history of congestive heart failure, digoxin can decrease the patient’s heart rate while not directly impacting the patient’s blood pressure. Digoxin is metabolized in the liver and excreted mostly by the kidneys and is typically found to be in an unchanged form in the urine (Stopfer et al., 2016). Digoxin is metabolized in the liver and the patient’s liver function was normal. The problem arises with excretion, the patient was found to have an acute kidney injury which would be a contraindication in the use of digoxin, however, the patients BPH was causing urinary retention which was influencing the AKI. Once the foley was placed, the patient was successfully excreting urine, eliminating the back up in the kidneys which will correct the AKI.

 

Plan of Care

 

Looking at all the data, the cardiologist felt comfortable with me administering the digoxin to the patient. In most clinical settings, we would treat a low blood pressure before treating CHF. The patient was started on continuous fluids at 125/hour rather than bolused with fluids in addition to a continuous infusion in hopes to avoid fluid overload. To address the afib with RVR, the plan was to administer a loading dose of digoxin to the patient via intravenous route at 8mcg/kg. This loading dose is split in half for the first dose and the other half is split into halves and administered every 8 hours for two doses. By splitting the doses, we can assess for toxicity in the event that kidney function is impaired. When the patient’s rate is controlled, the plan is to switch to PO digoxin which will be taken daily for maintenance. Once the patient is discharged, the cardiologist will see the patient outpatient to assess the need for adjustment of the digoxin dose based off of the effectiveness of the current dose as well as levels of drug in the body.

References 

Chokesuwattanaskul, R., Shah, N., Chokesuwattanaskul, S., Liu, Z., & Thakur, R. (2020). Low-dose Amiodarone Is Safe: A Systematic Review and Meta-analysis. The Journal of innovations in cardiac rhythm management, 11(4), 4054–4061. https://doi.org/10.19102/icrm.2020.110403

Ko, D., Rahman, F., Schnabel, R. B., Yin, X., Benjamin, E. J., & Christophersen, I. E. (2016). Atrial fibrillation in women: epidemiology, pathophysiology, presentation, and prognosis. Nature reviews. Cardiology, 13(6), 321–332. https://doi.org/10.1038/nrcardio.2016.45

 

Stopfer, P., Giessmann, T., Hohl, K., Sharma, A., Ishiguro, N., Taub, M. E., Zimdahl-Gelling, H., Gansser, D., Wein, M., Ebner, T., & Müller, F. (2016). Pharmacokinetic Evaluation of a Drug Transporter Cocktail Consisting of Digoxin, Furosemide, Metformin, and Rosuvastatin. Clinical pharmacology and therapeutics, 100(3), 259–267. https://doi.org/10.1002/cpt.406

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