ZESTOPRIL H 20
- Zestopril®-H contains two active ingredients, lisinopril and hydrochlorothiazide.
- Lisinopril is a peptidyl dipeptidase inhibitor. It inhibits the angiotensin converting
enzyme (ACE) that catalyses the conversion of angiotensin I to the vasoconstrictor
peptide, angiotensin II. Angiotensin II also stimulates aldosterone secretion by the
adrenal cortex. Inhibition of ACE results in decreased concentrations of angiotensin
II which results in decreased vasopressor activity and reduced aldosterone secretion.
The latter decrease may result in an increase in serum potassium concentration.
- Hydrochlorothiazide is a diuretic and an antihypertensive agent. It affects the distal
renal tubular mechanism of electrolytes reabsorption and increases excretion of
sodium and chloride in approximately equivalent amounts. Natriuresis may be
accompanied by some loss of potassium and bicarbonate. The mechanism of the
antihypertensive effect of the thiazides is unknown. Thiazides do not usually affect
normal blood pressure.
- Concomitant administration of lisinopril and hydrochlorothiazide has little or no
effect on the bioavailability of either drug. The combination tablet is bioequivalent
to concomitant administration of the separate entities.
- After oral administration of lisinopril peak serum concentration occurs within about
7 hours. Absorption is not affected by the presence of food.
- Lisinopril does not appear to be bound to serum proteins, studies in rats indicate that
lisinopril crosses the blood-brain barrier poorly.
- Lisinopril does not metabolize and is excreted entirely unchanged into the urine.
Lisinopril crosses the placental barrier and appears in cord blood. It is not known
whether lisinopril is secreted in human milk or not.