PRES3005: Critically analyse the different prescribing decisions that could be made in the management of a specific condition: Pharmacology for Prescribers Essay, UOS, UK

Critically analyse the different prescribing decisions that could be made in the management of a specific condition.

Introduction

Hypertension is defined as diastolic blood pressure (BP) greater than 140 mmHg and a systolic BP >90 mmHg when measured on two separate days (WHO, 2021). Current estimates suggest that ~1.28 billion adults over 30 globally suffer from the condition, which is a major contributor to cardiovascular disease deaths (WHO, 2021). For an adult >45 years of age without a diagnosis of hypertension, the 40-year risk for developing the condition varies between ethnic groups. A study from England found the odds of being hypertensive were higher in black men, black women, and South Asian men, compared to their white counterparts (Primatesta et al., 2000), illustrating the high prevalence and importance of genetic and societal social factors that need to be considered prior to prescribe medications (Whelton et al., 2018).

Physiologically, though hypertension itself may not lead to over clinical phenotypes, the condition increases the risk of several cardiovascular diseases and associated conditions, such as stroke, coronary artery disease, heart failure, vision loss, chronic kidney disease, and dementia, all of which are important co-morbidities for other common, non-communicable diseases of modernity, such as type 2 diabetes (Cannon, 2007). At present, although there are several treatment options to reduce BP, there is no known cure for hypertension. Moreover, the etiology of the condition is poorly understood (Brown & Haydock, 2000).

Given the large range of treatment options for hypertension, a detailed understanding of prescribing guidelines is imperative amongst healthcare professionals. Indeed, according to the Royal Pharmaceutical Society, quality prescribing for hypertension needs to carefully consider the medical evidence-based; patient safety; patient-specific disease features; the pharmacological implications of a given treatment (Royal Pharmaceutical Society, 2022). Moreover, to empower the patient to better manage his/her condition, patient health literacy should be assessed (and extended, if needed) so that treatment decisions can be made in collaboration between the healthcare provider and patient, ensuring patient-centered care (Ernst, 2007; Stewart, 2001). Furthermore, prescribing decisions should be consulted and agreed upon amongst the wider healthcare team to ensure the most appropriate options have been considered and to facilitate the continuity of care for an individual.

This article will explore the prescribing practices and treatment options for moderate and severe hypertension, focusing on Angiotensin-converting enzyme inhibitors, diuretics, calcium channel blockers, and angiotensin receptor blockers, given the wide evidence-based for their use. Sources used for evaluating prescribing practices in this piece of work include the most recent guidelines from the National Institute for Healthcare Excellence (NICE, UK), the Royal Pharmaceutical Society (UK), and the Healthcare Professionals Council (HCPC, UK).

Pathophysiology and drug treatment options

Hypertension is a chronic condition that manifests as persistently elevated BP, and the risk of developing the condition is associated with increasing age and certain lifestyle factors, such as tobacco and alcohol consumption; stress; low levels of physical exercise; and a high fat/salt diet. Familial history can also impart a genetic risk factor to different ethnic populations (Ranasinghe et al., 2015), though it is not the primary driver of disease in the majority of cases. Persistently elevated BP can lead to arterial stiffness, increased pulse pressure, and several cardio-circulatory complications and causes of death, including cardiac arrest, cerebral hemorrhage, heart failure, and kidney damage (Standring, 2020).

Based on resting BP, hypertension can be classified as mild (140-159/90-99 mmHg), moderate (160-179/100-109 mmHg), or severe (>180/100 mmHg) (NICE, 2019). These categories are important for determining the most appropriate therapeutic intervention, which ultimately aims to lower a patient’s circulatory pressure to healthy levels. When hypertension is diagnosed, tissue-specific examinations and analyses for signs of associated organ damage should be carried out (Boone & Kuo, 2018, NICE, 2019), as this will affect the choice of medical management. Such approaches may also illuminate the reason for the patient’s hypertension, be it a primary or secondary manifestation of concomitant comorbidities.

In many instances, mild hypertension can be managed clinically through the modification of lifestyle factors alone, such as weight loss, increasing exercise levels, and improving dietary quality (NICE, 2019; Whelton et al., 2018). However, when lifestyle modifications do not suffice, the pharmaceutical choices should be governed by safety and efficacy considerations.

Randomized control trials over the past 70 years have demonstrated that controlling hypertension by pharmaceutical means is safe and reduces the risk of heart disease, stroke, peripheral vascular disease, chronic renal disease, congestive heart failure, and other associated causes of mortality (Zanchetti et al., 2015). Indeed, many hypertensive drugs are on the WHO’s list of essential medicines and are critical for mitigating the high burdens the condition places on public healthcare systems. Worryingly, however, recent data suggest that pharmaceutical management of hypertension does not appropriately control BP in most patients, which can be attributed to a lack of treatment compliance, as well as poor prescribing practices (Fitz-Simon et al., 2005).

Initial first-line therapies for lifestyle-non-responsive hypertension include thiazide diuretics (that increase water expulsion and lower circulatory blood volume), calcium channel blockers (CCBs, that directly influence the generation of aldosterone), angiotensin-converting enzyme (ACE) inhibitors (that inhibit the angiotensin system that regulates BP), and angiotensin receptor blockers (ARBs, that work similarly to ACE inhibitors but target the receptors rather than the biosynthetic enzymes of the pathway) (NICE, 2019).

Two first-line drugs in combination (typically a diuretic and an ACE inhibitor) are recommended for most cases of moderate hypertension, as combination therapy reduces the concentrations of each individual component (reducing side-effects associated with each drug) and helps modulate different physiological systems that impinge upon hypertension development. Occasionally, patients may be started on an ACE inhibitor alone, For some time evidence has suggested that such combinations have a greater clinical benefit (Brown & Haydock, 2000; Wright et al., 2018). Once-daily, rather than twice-daily drug dosing, has also been found to improve treatment compliance and should be a target of the treatment regimen (Flack & Nasser, 2011). In this respect, Bendroflumethiazide is an ideal diuretic, given its long half-life in plasma and good efficacy (Sica et al., 2011). Thiazides hinder the reabsorption of sodium and chloride ions from the blood by inhibiting the sodium-chloride symporter of the kidney, thereby increasing fluid loss through urination, and reducing peripheral resistance. Numerous clinical trials have shown diuretics to improve hypertension-associated phenotypes and improve patient outcomes (Roush & Sica, 2016). As they are relatively inexpensive and have a good safety profile, they are widely used globally for this condition.

Alongside a diuretic, ACE inhibitors (such as Ramipril ) are the typical first choice prescription medication for hypertension. This class of drugs works by blocking the conversion of angiotensin I to angiotensin II, which is required to increase BP in response to nervous stimulation. The outcome of ACE inhibitor treatment is reduced arterial resistance and cardiac output and increased venous capacity and urinary excretion of sodium. Several clinical trials and real-world data have demonstrated the benefits of these drugs in different ethnic groups and age ranges for lowering the risk of stroke, cardiac arrest, and heart failure (Wright et al., 2018). In most cases of moderate hypertension, ACE inhibitors should be titrated to achieve systolic BP <130/80 mmHg after the patient has started on a diuretic (Whelton et al., 2018).

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