Assignment: Pharmacotherapy for Cardiovascular Disorders How changes in the processes might impact the patient’s recommended drug therapy
Volume of distribution of a drug is the overall quantity of the drug in the body of an individual relative to the
Assignment Pharmacotherapy for Cardiovascular Disorders
concentration of the drug in a certain body compartment and offers an estimation of the level to which the drug is distributed/delivered into oft tissues. Cohen (2017) indicates that patients with obesity are likely to have expanded plasma volume, which may change the volume of distribution. This leads to considerable differences in plasma concentration of some drugs in patients with obesity compared to patients with normal weight, despite comparable soft tissue concentrations. Particularly, the volume of distribution of lipophilic drugs is impacted by excess adiposity. These medications tend to easily diffuse into adipose tissue, which makes it hard to attain therapeutic plasma levels (Cohen, 2017).
NAFLD plays a significant role in the dysfunctional clearance of medications in obesity. Cohen et al.(2017) indicate that Hepatic steatosis contributes to reduced hepatic microvascular blood flow, leading to an altered delivery of medications to the liver. Also, NAFDL causes abnormal function of hepatic enzymes, resulting in both decreased and increased rates of hepatic clearance of drugs. According to Cohen (2017), altered renal clearance is another crucial factor that makes the predictability of clearance of medication in obesity complex. Because obesity is connected with amplified glomerular hyperfiltration and amplified cardiac output, patients with obesity can experience faster medication clearance compared to patients with normal weight.
Obese patients respond differently to treatment with certain hypertensive drugs compared to non-weight patients, an indication that obese patients are vulnerable to atypical responses to drugs. Because there is upregulation of rennin-angiotensin aldosterone system activity and SNS activity, inhibition of these neurohormonal pathways contributes to amplified hemodynamic responses in obese individuals whose hypertension is not resistant to treatment. For example, an in vivo study involving a direct measure of renal hemodynamic revealed that patients with obesity had a higher renal vasodilatory response to angiotensin-converting enzyme inhibition with captopril compared to non-obese patients (Cohen, 2017).
How I might improve the patient’s drug therapy plan
I would improve the patient’s drug therapy plan by replacing atenolol and doxazosin with an angiotensin-converting enzyme inhibitor (ACEI) and angiotensin II receptor blocker (ARB). Atenolol and doxazosin is beta-blocker and alpha-blocker respectively. I would make this recommendation because ACES and ARBs that medications target the mechanism of obesity-related hypertension. According to Shariq and McKenzie, (2020), while the majority of hypertension guidelines fail to address patients with obesity as a unique population, some recommendations for optimal choice for agents for controlling blood pressure in obese patients have emerged. Due to the role that the RAA plays in the pathogenesis of hypertension in obese individuals, there is strong evidence for considering ARBs and ACEIs as first-line therapies. ARBs and ACEIs effectively lower blood pressure by inhibiting the renin-angiotensin system. These medications have the added benefit of improving insulin sensitivity which is a common comorbidity in individuals with obesity (Shariq and McKenzie, 2020). Cataldi et al.(2016), emphasize that medications targeting the RAA system could be a practical choice because of the release of aldosterone and angiotensin- II from the adipose tissue. Although beta-blockers counteract the overactivation of the SNS, these drugs are associated with insulin resistance and weight gain.
References
Cataldi, M., di Geronimo, O., Trio, R., Scotti, A., Memoli, A., Capone, D., & Guida, B. (2016). Utilization of antihypertensive drugs in obesity-related hypertension: a retrospective observational study in a cohort of patients from Southern Italy. BMC Pharmacology and Toxicology, 17, 9. https://doi.org/10.1186/s40360-016-0055-z
Cohen, J. B. (2017). Hypertension in Obesity and the Impact of Weight Loss. Current Cardiology Reports, 19(10), 98. doi: 10.1007/s11886-017-0912-4
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