Effectiveness Of Losartan Usage In Hypertension Treatment And Its Side Effects

Hypertension is a condition in the body when the blood pressure is higher than the normal blood pressure, greater than 140mmHg/90mmHg. Vasoconstriction is a major factor in increase of blood pressure (Shankie, 2001). The heart is an organ which main function is to circulate blood through the body. Normally a heart would be able to circulate blood as long as the human is alive in a controlled manner. When blood pressure is high, peripheral vascular resistance increases, which means it becomes more difficult for the heart to pump blood from and to the body (Brest & Altchek, 1969; Mitsnefes, Knilans, Mays, Khoury, and Daniels; 2005).

This condition increases the workload of the heart which means the heart would try to pump harder and/or more frequently, eventually, the left ventricular muscle cell will increase in mass, subsequently, the left ventricular muscle tissue’s elasticity will decrease in a condition called left ventricular hypertrophy. Left ventricular hypertrophy compromises the heart’s ability to pump blood and could lead to various complications such as; hepatic congestion, peripheral edema, blood clot, heart failure, heart arrythmia, etc (Brest & Altchek, 1969).

Symptoms of hypertension complication may include; chest pain, shortness of breath, fatigue, and feeling of tightness in the chest area ('Hypertensive Heart Disease: Types, Symptoms, and Diagnosis', 2019). Losartan, a drug could reduce vasoconstriction, could be used to reduce blood pressure and to treat hypertension.

Losartan works in a system in our body called the Renin-Angiotensin System (RAS). The RAS is a system which maintains blood electrolyte level, blood pressure, and water reabsorption in the kidney. First of all, renin, an enzyme secreted to the blood by certain cells in the kidney, converts a plasma protein, angiotensinogen, into a peptide called angiotensin I. An enzyme called angiotensin-converting enzyme (ACE) then converts angiotensin I into angiotensin II. Angiotensin II is a hormone which binds to a receptor in the adrenal gland called the angiotensin II type-1 receptor which is a G-Protein coupled receptor (GPCR) (Amy Barreras, 2019; ('renin-angiotensin system | Definition & Facts', 2019).

Upon binding of the angiotensin II type-1 receptor by angiotensin II hormone, the receptor will activate and start to transmit messages into and out of the cell (GUO, SUN, HAMET & INAGAMI, 2001)). One result from this process is the contraction of smooth muscle of the blood vessel, in another word, it results in blood vessel constriction (vasoconstriction). Vasoconstriction due to angiotensin II binding to its receptor will increase blood pressure and could result in hypertension which will eventually lead to other complications that could be fatal.

Losartan is an antihypertensive drug in a class called the angiotensin II receptor blockers (ARBs). Losartan is a selective angiotensin II type-1 receptor antagonist, which means it specifically binds to angiotensin II type-1 receptor without activating the receptor, therefore, blocking disallowing angiotensin II to bind to the receptor (Amy Barreras, 2019;'Losartan', 2019; 'Losartan - DrugBank', 2019). Blocking the angiotensin II type-1 receptor- which would usually induce increase in blood pressure by vasoconstriction- would reduce the overall vasoconstriction which has already happened throughout the body, hence, reducing the blood pressure of the patient.

The reduction of the initially high blood pressure would correspond to the reduction of peripheral vascular resistance, subsequently, reduction of the workload of the heart. This means that potentially, it could treat early stages of hypertrophic left ventricular muscle, hence, reducing the possibility of contracting hepatic congestion, peripheral edema, blood clot, heart failure, etc. But it would be difficult to treat chronic left ventricular hypertrophy with an antihypertensive drug (Araujo et al., 2005; Karamyan, Tadevosyan & MacLaughlin, 2011). Losartan is most commonly prescribed on its salt form (Losartan Potassium) and its administration includes oral administration.

Reported adverse effects of losartan may include mild dizziness, angioedema (area of swelling of the lower skin, a rare but possibly life-threatening adverse effect of losartan potassium), and hypotension which could be a result of prolonged use of losartan due to the constant inhibition of the angiotensin II type-1 receptor which results disables the body’s ability to induce vasoconstriction. Losartan works best on patients who are intolerant to angiotensin- converter enzyme inhibitors (ACE inhibitors), another class of antihypertensive drugs with certain adverse effects, and patients with mild to severe essential hypertension (LM, 2019). In conclusion, Losartan is a suitable drug to be used to treat mild to severe essential hypertension because of its selective inhibitor characteristic, its effects on its inhibitory process, its low rate of adverse effects, and its ease of administration (as simple as oral administration).

But, usage of losartan should be supervised due to its possible adverse effects and the rare but possibly fatal side effect, angioedema. Additionally, prolonged usage of losartan (years of usage) should be avoided since it could lead to hypotension, blood pressure lower than the normal blood pressure, which could lead to other complications in one’s body.