Olmesartan 20 mg + Hydrochlorothiazide 12.5 mg
BRAND NAME: OLMEZON-H TABLET
COMPOSITION:-each tablet contains 20mg olmesartan and 12.5mg hydrochlorthiazide
Packing: – 10*10
1. Pharmacodynamics: –
a.) Olmesartan: – Angiotensin II is formed from angiotensin I in a reaction catalyzed by angiotensin converting enzyme (ACE, kininase II). Angiotensin II is the principal pressor agent of the renin-angiotensin system, with effects that include vasoconstriction, stimulation of synthesis and release of aldosterone, cardiac stimulation and renal reabsorption of sodium. Olmesartan blocks the vasoconstrictor effects of angiotensin II by selectively blocking the binding of angiotensin II to the AT1 receptor in vascular smooth muscle. Its action is, therefore, independent of the pathways for angiotensin II synthesis.
b.) Hydrochlorthiazide: -Hydrochlorothiazide is a thiazide diuretic. Thiazides affect the renal tubular mechanisms of electrolyte reabsorption, directly increasing excretion of sodium and chloride in approximately equivalent amounts. Indirectly, the diuretic action of hydrochlorothiazide reduces plasma volume, with consequent increases in plasma renin activity, increases in aldosterone secretion, increases in urinary potassium loss, and decreases in serum potassium. The renin-aldosterone link is mediated by angiotensin II, so co-administration of an angiotensin II receptor antagonist tends to reverse the potassium loss associated with these diuretics.
2. Pharmacokinetics: –
a.) Olmesartan: –
- Metabolism and Excretion: – Following the rapid and complete conversion of olmesartan medoxomil to olmesartan during absorption, there is virtually no further metabolism of olmesartan. Total plasma clearance of olmesartan is 1.3 L/h, with a renal clearance of 0.6 L/h. Approximately 35% to 50% of the absorbed dose is recovered in urine while the remainder is eliminated in feces via the bile.
- Distribution: – The volume of distribution of olmesartan is approximately 17 L. Olmesartan is highly bound to plasma proteins (99%) and does not penetrate red blood cells. The protein binding is constant at plasma olmesartan concentrations well above the range achieved with recommended doses.
b.) Hydrochlorthiazide: –
- Metabolism and Excretion: – Hydrochlorothiazide is not metabolized but is eliminated rapidly by the kidney. At least 61% of the oral dose is eliminated unchanged within 24 hours.
- Distribution: – Hydrochlorothiazide crosses the placental but not the blood-brain barrier and is excreted in breast milk.
- A combination of Olmesartan, an angiotensin II receptor antagonist and hydrochlorothiazide, a thiazide diuretic.
- Provides significant BP reductions and better BP control
- Reduces BP more effectively than either gent alone
- Improves cardiovascular prognosis in hypertensive patients.
- Offers better patient Compliance.