Valsartan

On December 23, 1996, the FDA approved Valsartan, an angiotensin II receptor blocker. Valsartan is used to treat hypertension, heart failure, and to prevent myocardial infarctions. Lowering blood pressure can lower the risk of heart failure and other cardiovascular events. Valsartan can also help diabetics avoid kidney problems.

BRAND NAMES:

Diovan - Diovan is a composition of valsartan available with strengths 40, 80, 160 and 320mg.

Prexxartan - Valsartan is the active ingredient present in prexxartan which is available as an oral solution 4 mg/mL aqueous solution.

MECHANISM OF ACTION:

Valsartan is an Angiotensin II blocker that works by locking angiotensin II, a powerful blood pressure regulator that narrows blood vessels, affects the production and release of aldosterone, stimulates the heart, and promotes sodium reabsorption by the kidneys. It blocks angiotensin II from binding to the AT1 receptor in many tissues such as blood vessel smooth muscle and the adrenal gland, lowering blood pressure.

PHARMACOKINETICS:

Absorption: It takes 2 to 4 hours to reach its peak plasma concentration after administration of the dose. The bioavailability of valsartan is 25%.

Distribution: The intravenous administration and volume of distribution of valsartan is 17L.

Metabolism: The primary metabolite is valeryl 4-hydroxy valsartan. In vitro metabolism, involves recombinant CYP450 enzymes indicating that the CYP2C9 isoenzymes are responsible for the formation of valeryl-hydroxy valsartan. It does not inhibit CYP450 isoenzymes.

Excretion: It is primarily excreted through feces about 83% of the dose and 13% of the dose through urine.

PHARMACODYNAMICS:

It shows the pressor effect of angiotensin II infusions. In hypertensive patients, negative angiotensin II causes a 2- to 3-fold increase in plasma renin, which leads to an improvement in angiotensin II plasma concentration. Valsartan treatment caused minimal decreases in plasma aldosterone and had little effect on serum potassium levels.

DOSAGE AND ADMINISTRATION:

Valsartan is available as tablets and oral solutions. The dosage will be suggested based on the patient's condition. The dosage can differ from patient to patient.

For high blood pressure in adults, the starting dose recommended is 80 -160mg once daily and can exceed 80 -320mg once daily.
For heart failure, the recommended dose is 40mg twice daily and can exceed between 40-160 mg twice daily.
For myocardial infarction, 20mg twice daily is recommended and the dose is between 20 -160mg twice daily.

CONTRAINDICATIONS:

Valsartan is contraindicated in patients with Hypersensitivity, diabetes mellitus, and kidney problems.

DRUG INTERACTIONS:

When taken with valsartan, certain medications may interact and have negative effects. It may also lessen the medication's efficacy. When taking valsartan, it is recommended to avoid the following medications.