How does Diovan work? Understanding Its Mechanism of Action

October 7, 2025 •

4 min read

Nearly half of adults in the U.S. have hypertension, a primary risk factor for cardiovascular disease [1.7.4, 1.7.1]. Understanding how does Diovan work is key to managing this condition, as it directly targets a hormone system that regulates blood pressure [1.3.3].

Quick Summary

Diovan's active ingredient, valsartan, is an angiotensin II receptor blocker (ARB) [1.3.1]. It lowers blood pressure by selectively blocking the AT1 receptor, which prevents blood vessels from constricting [1.2.1, 1.2.2].

Key Points

Mechanism of Action: Diovan (valsartan) is an ARB that works by blocking the AT1 receptor, preventing the hormone angiotensin II from constricting blood vessels [1.2.1, 1.2.3].
Primary Uses: It is prescribed to treat high blood pressure (hypertension), reduce hospitalizations for heart failure, and lower the risk of death after a heart attack [1.3.1].
Blood Pressure Reduction: By relaxing and widening blood vessels, Diovan lowers blood pressure and makes it easier for the heart to pump blood [1.3.4, 1.3.5].
Comparison to ACE Inhibitors: Unlike ACE inhibitors, Diovan does not affect bradykinin levels, resulting in a much lower incidence of a dry cough, a common side effect of ACE inhibitors [1.2.1, 1.6.3].
Important Safety Information: Diovan is contraindicated in pregnancy due to the risk of fetal harm (FDA boxed warning) and can cause side effects like dizziness, high potassium, and kidney problems [1.3.3, 1.9.3].

Understanding Diovan (Valsartan)

Diovan, with its active ingredient valsartan, is a widely prescribed medication primarily used to treat high blood pressure (hypertension) and heart failure [1.3.1, 1.3.4]. It is also used to improve survival rates after a heart attack [1.3.2]. Valsartan belongs to a class of drugs known as angiotensin II receptor blockers, or ARBs [1.2.3]. By managing high blood pressure, Diovan helps reduce the risk of serious cardiovascular events like strokes and heart attacks [1.2.3, 1.3.5]. The medication is available in tablet form and is typically taken once or twice daily, with or without food [1.3.4, 1.5.4]. It is considered a long-term treatment for chronic conditions [1.3.3].

How Does Diovan Work: The Core Mechanism

The primary way Diovan functions is by interfering with the renin-angiotensin system, a crucial hormone system for regulating blood pressure and fluid balance in the body [1.3.3, 1.6.4].

Angiotensin II Production: The body produces a hormone called angiotensin II, which is a potent vasoconstrictor, meaning it causes blood vessels to narrow or tighten [1.2.3, 1.3.3]. Angiotensin II also stimulates the release of another hormone called aldosterone, which causes the body to retain sodium and water, further increasing blood volume and pressure [1.2.5, 1.3.1].
Receptor Blockade: Valsartan works by selectively blocking the binding of angiotensin II to its primary receptor, known as the AT1 receptor [1.2.1, 1.2.2]. These receptors are found in many tissues, including the smooth muscle of blood vessels [1.2.3].
Vasodilation and Blood Pressure Reduction: By blocking the AT1 receptor, valsartan prevents angiotensin II from exerting its constricting effect. This allows the blood vessels to relax and widen, a process called vasodilation [1.2.2, 1.3.4]. The widening of blood vessels lowers peripheral resistance, making it easier for the heart to pump blood, which ultimately results in lower blood pressure [1.2.2, 1.3.5].

This targeted mechanism means Diovan's action is independent of the pathways for angiotensin II synthesis [1.2.1]. The substantial antihypertensive effect is typically seen within two weeks of starting treatment, with the peak effect reached after about four weeks [1.2.3].

What is Diovan Prescribed For?

Doctors prescribe Diovan for several cardiovascular conditions:

High Blood Pressure (Hypertension): It is approved for use in adults and children (ages 1 year and older for the brand Diovan, 6 years and older for generic valsartan) to lower high blood pressure [1.2.3, 1.3.3].
Heart Failure: It is used in adults to reduce the risk of hospitalization for heart failure (specifically NYHA class II-IV) [1.2.3, 1.3.3].
Post-Heart Attack (Myocardial Infarction): Diovan is prescribed to stable adult patients after a heart attack to reduce the risk of cardiovascular death, particularly in those with heart dysfunction [1.2.3, 1.3.3].

Comparison: Diovan (ARB) vs. ACE Inhibitors

Diovan (an ARB) is often compared to another class of blood pressure drugs called angiotensin-converting enzyme (ACE) inhibitors, like lisinopril. Both affect the renin-angiotensin system but in different ways.


Feature	Diovan (Valsartan - ARB)	ACE Inhibitors (e.g., Lisinopril)
Mechanism	Blocks angiotensin II from binding to the AT1 receptor [1.2.1].	Prevents the formation of angiotensin II by inhibiting the angiotensin-converting enzyme (ACE) [1.2.1, 1.6.2].
Effect on Bradykinin	Does not inhibit the degradation of bradykinin [1.2.1].	Inhibits the degradation of bradykinin, which can accumulate [1.6.4].
Common Side Effect: Cough	Less likely to cause a dry cough. The incidence is significantly lower than with ACE inhibitors [1.6.3].	A persistent, dry cough is a well-known side effect, caused by the accumulation of bradykinin [1.6.1, 1.6.4].
Effectiveness	Studies have shown both drug classes to be similarly effective in lowering blood pressure [1.6.2, 1.6.3].	Both drug classes are considered effective first-line treatments for hypertension [1.6.2, 1.6.3].

Because ARBs do not affect bradykinin levels, they are often prescribed as an alternative for patients who cannot tolerate the cough associated with ACE inhibitors [1.3.4, 1.6.4].

Potential Side Effects and Important Precautions

While effective, Diovan can cause side effects. Common, milder side effects include dizziness, headache, fatigue, and diarrhea [1.4.1, 1.4.3]. Dizziness is one of the most frequently reported side effects and may occur when first starting the medication or if blood pressure drops too low [1.4.3, 1.4.5].

Serious side effects are less common but require immediate medical attention:

Low Blood Pressure (Hypotension): Can cause significant dizziness or fainting [1.9.3].
Kidney Problems: In some cases, valsartan can affect kidney function, especially in those with pre-existing kidney disease or severe heart failure [1.3.1, 1.9.3]. Your doctor will monitor kidney function periodically [1.3.1].
High Potassium Levels (Hyperkalemia): Valsartan can increase potassium levels in the blood. Patients should avoid potassium supplements and salt substitutes containing potassium unless directed by their doctor [1.3.4, 1.11.2].
Angioedema: A rare but serious allergic reaction causing swelling of the face, lips, tongue, and throat, which can make breathing difficult [1.4.1].

Black Box Warning: Diovan has a boxed warning from the FDA, the most serious type. It should not be used during pregnancy as it can cause injury or death to a developing fetus. If pregnancy is detected, the drug must be stopped immediately [1.3.3, 1.8.3].

Conclusion

Diovan works by precisely targeting and blocking the AT1 receptor, preventing the hormone angiotensin II from tightening blood vessels. This mechanism effectively lowers blood pressure and reduces the strain on the heart, making it a cornerstone therapy for managing hypertension, heart failure, and improving outcomes after a heart attack. Its key advantage over ACE inhibitors is a significantly lower risk of causing a dry cough, providing a valuable alternative for many patients. As with any prescription medication, it is vital to take Diovan as directed by a healthcare provider and be aware of its potential side effects and necessary precautions.

Authoritative Link: For detailed prescribing information, you can visit the FDA's database for Diovan's official label [1.5.1].

Frequently Asked Questions

For lowering blood pressure, Diovan (valsartan) starts to work within about 2 hours after a dose, with its maximum effect occurring at around 6 hours. However, it may take up to four weeks to achieve the full blood pressure-lowering benefit [1.10.1, 1.2.3].

The main difference is their mechanism and a key side effect. Diovan, an ARB, blocks the action of angiotensin II at the receptor level. ACE inhibitors block the production of angiotensin II. Because of this difference, ACE inhibitors can cause a persistent dry cough, which is much less common with Diovan [1.6.1, 1.6.3].

Yes, you can take Diovan (valsartan) with or without food. It is recommended to take it around the same time each day to maintain steady levels of the medication in your body [1.5.4, 1.11.4].

The most common side effects of Diovan include dizziness, headache, fatigue, back pain, and joint pain [1.4.1, 1.4.3]. Dizziness is particularly common when first starting the medication or if your blood pressure becomes too low [1.4.3].

Diovan carries a serious FDA warning because it can cause harm or death to a developing fetus, particularly if taken during the second and third trimesters. It must be stopped immediately if pregnancy occurs [1.3.3, 1.8.3].

Yes, Diovan can cause high blood potassium levels (hyperkalemia). It is important to avoid potassium supplements and salt substitutes containing potassium while taking this medication, unless your doctor advises otherwise [1.3.4, 1.11.3].

If you miss a dose, take it as soon as you remember. However, if it is almost time for your next scheduled dose, skip the missed dose and resume your regular schedule. Do not take two doses at once to make up for a missed one [1.3.3, 1.11.4].