Pharmacodynamics

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.

 

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Pharmacokinetics and Pharmacodynamics

A solid understanding of how drugs impact the body is essential. Pharmacokinetics explains how the body metabolizes drugs, and pharmacodynamics describes the effect of the drug on the body. This post will explore a patient case, including factors that might have altered the patient response to medication therapy and a discussion of a personalized plan of care for the above patient.The case is about an adverse drug reaction (ADR).

According to Rosenthal and Burchum (2018), there has been a dramatic increase in ADRs despite efforts to reduce them. Although many of these events are preventable with careful prescribing, some are not. About two years ago, I went to work and received morning report for my patients. One particular patient stood out. He was an otherwise healthy 19-year-old with no known medication allergies, no active home medications, or medical conditions. The prior evening, he had become agitated because he wanted to leave the hospital and received Haldol 5 mg, Ativan 2 mg, and Benadryl 50 mg. I went to assess him and saw him unresponsive to his environment, standing at the wall, facing it, and mumbling. He was not alert to person, place, time, nor situation. I immediately suspected rhabdomyolysis and alerted the provider. The provider looked at him and stated: “he is just crazy.” I explained the patient history and demanded an order to send the patient to the emergency department (ED), which occurred. Later on, I called the ED, and the diagnosis was indeed rhabdomyolysis. It would be too easy to state that the scenario above was merely an unfortunate adverse event. Dr. Buttaro had it correct when she mentioned in the video that prescribing is about ensuring the right drug, right patient, right time, and the right dose (Laureate Education, 2019). I believe that a different medication choice in the scenario would have prevented rhabdomyolysis or lower doses.

The most likely etiology of the rhabdomyolysis was the administration of these medications. I do not think genetics, sex, age, ethnicity, or existing disease impacted this scenario. All three drugs increase the risk of developing rhabdomyolysis, especially for someone who had never taken antipsychotics or benzodiazepines (Stanley & Adigun, 2018). My plan of care for the patient would include verbal de-escalation as the first line of treatment and a low dose of hydroxyzine for agitation if needed. This medication choice would most likely be sufficient for someone who does not take medications at all. A safe rule for a prescriber is to go low and slow when prescribing drugs and monitor responses to therapy accordingly.