Hypertension (HTN) is the leading cause of cardiovascular morbidity and mortality worldwide, and it raises the risk of stroke, heart disease, kidney failure, and other debilitating complications. The two major physiological factors that antihypertensive drugs target are cardiac output (CO) and peripheral resistance (PR) both play crucial roles in blood pressure control. By altering these determinants, these medications reduce the heart’s workload and prevent the long-term consequences of untreated HTN (Santisteban et al., 2023). Some antihypertensive medications result in reduced cardiac output, that is, the amount of blood expelled by the heart per unit of time. This is done with beta-blockers such as metoprolol or atenolol, which win and compete for beta-adrenergic receptors and thus reduce heart rate and myocardial contractility. It leads to a reduced stroke volume and, therefore, reduced cardiac output. Calcium channel blockers, such as diltiazem and verapamil (Hill et al., 2022), slow the heart rate and reduce contractility by blocking calcium influx into cardiac muscle cells, thus further decreasing cardiac output. Diuretics that have hydrochlorothiazide and furosemide reduce blood volume, resulting in the reduction of CO because they lower blood volume. They decrease preload and overall cardiac output by increasing the amount of sodium and water excreted by the kidneys, decreasing the fluid in the blood. Two additional classes of other antihypertensive drugs reduce peripheral resistance, or the force that opposes blood flow through the arterial system. Blocking the renin-angiotensin-aldosterone system (RAAS) is one of the predominant ways to achieve this (Budiarto et al., 2023). ACE inhibitors, lisinopril, enalapril, and angiotensin receptor blockers (ARBs), losartan, and valsartan prevent the action or formation of angiotensin II, a powerful vasoconstrictor. This causes the blood vessels to be relaxed, the vascular resistance to decrease, and the blood pressure to decrease. Moreover, calcium channel blockers like amlodipine and nifedipine cause direct vasodilation by inhibiting calcium entry into vascular smooth muscle, thereby inducing arterial relaxation and decreasing PR. Prazosin and doxazosin are alpha-blockers, and they work by blocking alpha-adrenergic receptors to stop them from vasoconstriction and maintain these dilated blood vessels. In more serious cases, direct vasodilators, either hydralazine or minoxidil can be given directly to vasodilate the vascular smooth muscle, rapidly decreasing the peripheral resistance and lowering blood pressure.
Untreated or undertreated hypertension can result in serious complications of multiple organ systems. In particular, the cardiovascular system is particularly vulnerable to these forces that continue for an extended period and take a strain on the heart, which then becomes hypertrophic, and this increases the risk of heart failure (Slone & Commodore-Mensah, 2024). Hypertension, therefore, predisposes to atherosclerosis and, subsequently, to myocardial infarction (heart attack), aortic aneurysm, and peripheral artery disease. With uncontrolled hypertension, there is an increased likelihood of ischemic and hemorrhagic strokes, where blood vessel damage to the brain is due to pressure ruptures or blocks. In addition, chronic hypertension is associated with vascular dementia and cognitive decline, as chronic hypertension induces cerebral perfusion (Yu et al., 2022). Another is the renal system. Suppose the glomeruli in the kidneys are damaged by high blood pressure in the long term. In that case, this may lead to chronic kidney disease (CKD) and, in the worst cases, to end-stage renal disease (ESRD), for which dialysis or transplantation is necessary. As well as the eyes, hypertension can cause hypertensive retinopathy (generated by hypertension that damages the retinal vessels, causing loss of vision or blindness). Furthermore, the peripheral vascular system is also in jeopardy because long-term hypertension can also lead to poor circulation, claudication (pain due to insufficient blood flow), and risk for limb ischemia. Because uncontrolled hypertension carries potentially life-threatening consequences, intervention, either pharmacologically, through meds, or in lifestyle, is essential early on. Prevention of complications and improvement of long-term health outcomes, therefore, requires regular blood pressure monitoring, adherence to antihypertensive medication, and lifestyle changes such as a healthy diet, routine exercise, smoking cessation, and stress reduction.
References
Budiarto, D., Wijianto, B., & Hariyanto, I. H. (2023). Study of anthocyanin molecule blocking as anti-hypertensive through the pathway of the renin-angiotensin-aldosterone system (RAAS). Indonesian Journal of Chemical Research, 11(1), 49-58. https://ojs3.unpatti.ac.id/index.php/ijcr/article/download/8131/5778
Hill, K., Sucha, E., Rhodes, E., Bota, S., Hundemer, G. L., Clark, E. G., … & Sood, M. M. (2022). Amiodarone, verapamil, or diltiazem use with direct oral anticoagulants and the risk of hemorrhage in older adults. CJC open, 4(3), 315-323. https://www.sciencedirect.com/science/article/pii/S2589790X21002997
Santisteban, M. M., Iadecola, C., & Carnevale, D. (2023). Hypertension, neurovascular dysfunction, and cognitive impairment. Hypertension, 80(1), 22-34. https://www.ahajournals.org/doi/abs/10.1161/HYPERTENSIONAHA.122.18085
Slone, S. E., & Commodore-Mensah, Y. (2024). Accurate Blood Pressure Measurement Is a Necessary but Insufficient Step to Diagnose and Control Hypertension. Circulation: Cardiovascular Quality and Outcomes, 17(2), e010738. https://www.ahajournals.org/doi/pdf/10.1161/CIRCOUTCOMES.123.010738
Yu, W., Li, Y., Hu, J., Wu, J., & Huang, Y. (2022). A study on the pathogenesis of vascular cognitive impairment and dementia: the chronic cerebral hypoperfusion hypothesis. Journal of Clinical Medicine, 11(16), 4742. https://www.mdpi.com/2077-0383/11/16/4742
