VPT 321: Veterinary Neuropharmacology (2+1)

ANGIOTENSIN ANTAGONIST

Angiotensin antagonist are Saralasin, Losartan

Saralasin

• An octapeptide analogue of Angiotensin II
• Exhibited partial agonistic activity
• Need parenteral administration only.

Losartan

• Competitive antagonist
• Devoid of partial agonistic activity
• Selective antagonist of AT₁ receptor
• Blocks all actions of Angiotensin II namely vasoconstriction, central and peripheral sympathetic outflow action, aldosterone release, salt and water reabsorption, growth promoting actions on heart and blood vessels.

Advantages

• Causes a fall in blood pressure lasting for 24 hours
• Regress hypertensive left ventricular hypertrophy 
• Food does not interfere with absorption
• Under goes first pass metabolism
• Dose should be reduced in hepatic dysfunction
• No recurrence of cough
• Incidence of foetal abnormalities have been recorded.