It is a partial agonist. It is a peptide analogue of angiotensin II.
Mechanism of action:
It competitively inhibits of angiotensin II receptors.
1. it blocks the vasoconstrictor and aldosterone releasing effects of angiotensin II and reduces blood pressure in increased renin states e.g. in renal artery constriction.
2. Due to its weak agonist activity it may increase Blood pressure by rapid administration to persons without increased circulating angiotensin II.
Its adverse effects are almost same to those of ACE inhibitors.
They are contraindicated in for pregnant woman.