Benicar HCT, Olmesartan
BENICAR HCT
Benicar HCT (OLMESARTAN MEDOXOMIL-HYDROCHLOROTHIAZIDE)
Manufactured by Sankyo Pharma is a combination of an angiotensin II receptor antagonist (AT1 subtype), olmesartan medoxomil, and a thiazide diuretic, hydrochlorothiazide (HCTZ).
Benicar HCT is used to treat hypertension.
What is angiotensin?
Angiotensin is a hormone and is mainly of two types, angiotensin 1 and angiotensin 2. It is a potent vasoconstrictor, meaning it constricts blood vessels, increasing the blood pressure. This function is achieved by stimulating the Gq protein in smooth muscle cells of the blood vessels which in turn activates contraction by an IP3-dependent mechanism. It is synthesized from angiotensinogen, a globulin which is procured from liver. Renin, found in the juxta glomerular apparatus of kidney converts this angiotensinogen to angiotensin 1.
Renin is secreted when there is a fall in the intra renal blood pressure or when there is decreased delivery of Na+ and Cl- to the macula densa.
Angiotensin 1 does not have any function of its own and is converted to angiotensin 2 by the enzyme Angiotensin Converting Enzyme [ACE].
The action of Angiotensin Converting Enzyme is blocked by a very popular group of drugs called as Angiotensin Converting Enzyme Inhibitors [ACE I]
There is also another group of drugs that act against the receptors of angiotensin 2, known as Angiotensin 2 Receptor antagonists.
Angiotensin II is the principal vasopressor agent of the renin-angiotensin system, with effects that include vasoconstriction, stimulation of synthesis and release of aldosterone, cardiac stimulation and renal re absorption of sodium ions.
Olmesartan medoxomil, a prodrug, is hydrolyzed to olmesartan during absorption from the gastrointestinal tract. It is an Angiotensin 2 Receptor type 1 antagonist. The type 1 receptor is known for its vasopressor actions whereas type 2 receptor does not have any vasopressor actions.
Olmesartan medoxomil, by blocking the type 1 receptor of angiotensin 2, inhibits the vasopressor action of Angiotensin Converting Enzyme
Hydrochlorothiazide, affect the renal tubular mechanisms of electrolyte re absorption, 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.
The mechanism of the antihypertensive effect of thiazides is not fully understood.
INDICATION:
It is indicated in the treatment of hypertension.
SIDE EFFECTS:
- Dizziness,
- gout,
- nausea,
- upper respiratory infection
CONTRAINDICATION:
Due to Olmesartan medoxomil
It is contraindicated in patients who are hypersensitive to any component of this product.
Because of the hydrochlorothiazide component, this product is contraindicated in patients with anuria or hypersensitivity to other sulfonamide-derived drugs.
It is contraindicated in pregnancy since it can lead to severe fetal or neonatal mortality and morbidity
Following conditions can lead to mortality/morbidity
- hypotension,
- neonatal skull hypoplasia,
- anuria,
- reversible or irreversible renal failure
- oligohydramnios,
- fetal limb
- contractures,
- craniofacial deformation and
- Hypo plastic lung development.
Due to Hydrochlorothiazide
- hepatic impairment
- hypersensitivity reactions
- systemic lupus erythematosus
DOSAGE:
The starting dose of Benicar HCT is one tablet containing 20 milligrams of olmesartan/ 12.5 milligrams of hydrochlorothiazide once daily. If needed, the dose may be increased every 2-3 weeks until the blood pressure is under control. The maximum dose is 40 milligrams of olmesartan/25 milligrams of hydrochlorothiazide once daily
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