NCIt definition : A non-peptide angiotensin II antagonist with antihypertensive activity. Upon administration,
losartan and its active metabolite selectively and competitively blocks the binding
of angiotensin II to the angiotensin I (AT1) receptor. This blocks the vasoconstricting
and aldosterone-secreting actions of angiotensin II, leading to a decrease in blood
pressure. Angiotensin II, formed from angiotensin I by angiotensin-converting enzyme
(ACE), stimulates the adrenal cortex to synthesize and secrete aldosterone, which
decreases the excretion of sodium and increases the excretion of potassium. Angiotensin
II also acts as a vasoconstrictor in vascular smooth muscle.;
Alternative definition : NCI-GLOSS: A drug used to treat high blood pressure. Losartan blocks the action of
chemicals that make blood vessels constrict (get narrower). It is a type of angiotensin
II receptor antagonist.;