DIOVAN 320 TABLETS

Indications

• Hypertension
• Heart failure
• Reduction of cardiovascular mortality in patients with left ventricular dysfunction following myocardial infarction

Dosage

Children: Refer to the BNF for Children for specific paediatric dosing guidelines.

Adults: Refer to the BNF for specific adult dosing guidelines based on the condition being treated.

Mechanism of action

Valsartan selectively antagonizes the angiotensin II type 1 (AT1) receptor, which mediates the effects of angiotensin II, including vasoconstriction and aldosterone secretion. By blocking this receptor, valsartan promotes vasodilation and decreases blood pressure, leading to improved cardiac output.

Pharmacodynamics

Valsartan's pharmacodynamic effects include a reduction in blood pressure and an improvement in cardiac function in patients with heart failure. The drug's antihypertensive effects can be observed within hours of administration, reaching peak effects typically within 2 to 6 hours. The duration of action can last up to 24 hours, allowing for once-daily dosing.

Pharmacokinetics

Valsartan is well absorbed after oral administration, with a bioavailability of approximately 23%. It is extensively metabolized in the liver, primarily by UDP-glucuronosyltransferase enzymes, and is excreted mainly through the bile and urine. The elimination half-life of valsartan is about 6 hours, but its antihypertensive effects can persist for 24 hours, allowing for once-daily dosing. The pharmacokinetics may be affected by renal impairment, and dose adjustments may be necessary in such patients.

Contra-indications

• Hypersensitivity to valsartan or any of the excipients.
• Severe hepatic impairment.
• Bilateral renal artery stenosis or unilateral stenosis in a solitary kidney.
• Pregnancy.

Adverse effects

• Dizziness.
• Hypotension.
• Hyperkalemia.
• Renal impairment.
• Cough.
• Fatigue.
• Nausea.

Interactions

• Potassium-sparing diuretics may increase the risk of hyperkalemia.
• Non-steroidal anti-inflammatory drugs (NSAIDs) may reduce the antihypertensive effect.
• Other antihypertensive agents may have additive effects.
• Lithium levels may increase when used with valsartan.

Precautions

• Monitor renal function, especially in patients with renal impairment.
• Use with caution in patients with a history of angioedema.
• Caution in patients with heart failure or aortic stenosis.
• Discontinue if pregnancy is detected.

Pregnancy

Valsartan is contraindicated during pregnancy due to potential harm to the fetus, particularly in the second and third trimesters.

Breast-feeding

It is not known whether valsartan is excreted in human milk. Caution is advised when administering to breastfeeding women.

Storage

Store at room temperature, away from moisture and heat. Keep out of reach of children.

Formulations

• Tablets (various strengths including 40 mg, 80 mg, and 160 mg).
• Oral solution.