Comparison of bleeding time changes in essential hypertension patients on losartan or amlodipine: a prospective observational study

Narendranath S., Srinivas LD, Arun S., Shashikala GH, Pallavi MK, Suresh SR, Imran Maniyar


Background: Hypertension leads to vascular damage due to high pressure exerted on arteriolar wall and also promotes atherothrombosis in large and medium sized blood vessels. Thrombosis is an extension of haemostasis and platelets have a crucial role in the formation of atherothrombosis. Increased platelet activity is a risk factor in hypertensive patients and leads to cardio- and cerebrovascular events and target organ damage. Anti-platelet aggregatory treatment in these high risk patients have become a crucial step in their treatment. Recent data indicate that angiotensin II type 1 blockers or AT1 receptor blockers (ARBs) like Losartan and dihydropyridine class of L-type calcium channel antagonist like Amlodipine have anti- platelet activity. These two classes of drugs are frequently administered in hypertensive either alone and in combinations. This study aims to compare the anti-platelet activity of Losartan and Amlodipine. Anti-platelet activity in addition to anti-hypertensive activity of these drugs would be beneficial in treating hypertensive who are at high risk of atherosclerosis and atherothrombosis, if they are selectively prescribed these agents.

Methods: This was an observational study. Sixty (n=60) patients diagnosed with essential hypertension, attending medicine outpatient department of a tertiary care hospital were enrolled in the study. Out of them thirty (n=30) were patients who were prescribed losartan. Rest of the patients (n=30) were ones prescribed amlodipine. It was ensured that the patients of both the groups were on respective medication for at least one month. Another thirty (n=30) normotensive subjects acted as control. The bleeding time was evaluated for all three groups using Duke method of bleeding time estimation.

Results: Data was analysed using SPSS software version 20. One way ANOVA was used to analyse the data. This was followed by post hoc Tukey’s test. The mean bleeding time(in minutes) of Losartan group was 2.583±0.263 SD, Amlodipine group was 2.214±0155 SD and control group was 1.998±0.198 SD. Statistically significant p value of <0.001 was observed in losartan and amlodipine groups.

Conclusions: Our study shows that the mean bleeding time of Losartan group and amlodipine group were significantly higher than that of Control group. It was further observed that the mean bleeding time of losartan was higher than that of amlodipine group indicating a better antiplatelet action by losartan than amlodipine. Additional antiplatelet activity could be desirable to treat hypertensive patients with high atherothrombotic and/or thromboembolic risk.


Losartan, Amlodipine, Hypertension, Bleeding time, Antiplatelet activity

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