Drug therapy is focused on blocking the renin-angiotensin system (RAS). The RAS is activated by renin catalyzes the conversion of angiotensinogen to angiotensin I, which is then transformed into active angiotensin II by angiotensin-converting enzyme (ACE). Angiotensin II is responsible for aldosterone production and release, vasoconstriction, reabsorption of sodium, increased inotropism and chronotropism, stimulation of thirst, vagus suppression and beta-adrenergic-receptor stimulation; thus, it leads to increases in blood volume and blood pressure (2). Hence, blocking the RAS ult

Some of the limitations to the findings in this study include the following. All angiotensin-receptor antagonists are least effective in patients whose dietary salt intake is high or in patients who have low-renin hypertension (3). Hence, potential unwanted effects from the drugs may result. Furthermore, the results may be negatively affected by other health problems that the subjects may have. Other health problems, such as diabetes, renal failure, chronic heart failure, and obesity, may affect the absorption, the clearance, the bioavailability, and the efficacy of the drugs, thereby, affecting the results.

In this experiment, of all the 200 subjects who underwent randomization, 100 were assigned to receive losartan and 100 to receive valsartan. The average daily doses were 50mg of losartan and 80mg of valsartan. Based on the pharmacokinetics of valsartan and losartan, valsartan is expected to reduce the mean arterial blood pressure more than losartan by at least 5 mm Hg in average. Since the expected data fits the assumptions for t-test, a one-tailed t-test for two independent samples is used to determine whether valsartan is more efficacious than losartan in treating African-American patients with mild to moderate hypertension. But first, a Cochran test is being done to test for homogeneity of variances in the two drugs. If the resulting C-value is equal to or greater than the table value, then the hypothesis of equal variances is rejected. Consequently, the appropriate t-test is used to calculate the t-value, which then gives the p-value. If the obtained p-value is less than or equal to 0.05, then the null hypothesis is rejected and the alternative hypothesis is accepted; meaning, valsartan is more efficacious than losartan. But, if the p-value is greater than 0.05, then the null hypothesis is accepted, meaning both drugs are equally efficacious in reducing high blood pressure. In this experiment, the t-value is estimated to be 10 (assuming that there is a homogeneity of variances) with a degree of freedom of 198. Hence, the p-value is calculated to be less than or equal to 0.0005, meaning valsartan is expected to be more efficacious than losartan, if all the assumptions were true.

In this experiment, similar to severa

Some topics in this essay:
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