Renin, synthesized by the kidneys, is released into the circulation where it acts on a plasma precursor to produce angiotensin I, which is converted by angiotensin-converting enzyme to angiotensin II, a potent vasoconstrictor that also causes release of aldosterone from the adrenals. Lisinopril blocks the conversion of angiotensin I to angiotensin II, leading to decreased BP, decreased aldosterone secretion, a small increase in serum potassium levels, and sodium and fluid loss.

Indications

Treatment of hypertension alone or in combination with thiazide-type diuretics
Adjunctive therapy in CHF for patients not responding adequately to diuretics and digitalis

Contraindications/cautions

Contraindicated in the presence of allergy to lisinopril or enalapril.
Use caution in the presence of impaired renal function, CHF, salt or volume depletion, and lactation.

Adverse effects

CNS: Headache, dizziness, insomnia, fatigue, paresthesias
GI: Gastric irritation, nausea, diarrhea, aphthous ulcers, peptic ulcers, dysgeusia, cholestatic jaundice, hepatocellular injury, anorexia, constipation
CV: Orthostatic hypotension, tachycardia, angina pectoris, MI, Raynaud's syndrome, CHF, severe hypotension in salt or volume depleted patients
Hematologic: Neutropenia, agranulocytosis, thrombocytopenia, hemolytic anemia, fatal pancytopenia
GU: Proteinuria, renal insufficiency, renal failure, polyuria, oliguria, frequency
Other: Angioedema (particularly of the face, extremities, lips, tongue, larnyx; death has been reported with airway obstruction); cough, muscle cramps, impotence