Can you take valsartan and hydralazine together?

October 8, 2025 •

4 min read

Nearly half of adults in the United States, or about 120 million people, have hypertension [1.7.1]. For many, a single medication isn't enough to control it, raising the question: can you take valsartan and hydralazine together for better results?

Quick Summary

Yes, valsartan and hydralazine can be prescribed together under a doctor's supervision. This combination therapy leverages their different mechanisms to effectively lower blood pressure, especially in complex cases of hypertension or heart failure.

Key Points

Yes, Under Supervision: Valsartan and hydralazine can be taken together, but only under the strict guidance of a healthcare provider to manage blood pressure [1.5.2].
Additive Effect: The main interaction is an enhanced blood pressure-lowering effect, which can be beneficial but also increases the risk of hypotension (low blood pressure) [1.2.1].
Different Mechanisms: Valsartan (an ARB) works by blocking a hormone that tightens blood vessels, while hydralazine (a vasodilator) directly relaxes artery walls [1.3.1, 1.4.2].
Increased Monitoring: Patients on this combination require more frequent monitoring of their blood pressure and heart rate to ensure safety and effectiveness [1.10.3].
Patient Awareness: Patients should be cautious when standing up to avoid dizziness and must report side effects like fainting, rapid pulse, or headache to their doctor [1.5.2].
Not a First-Line Combo: This combination is typically reserved for patients with resistant hypertension or specific heart failure cases not controlled by other therapies [1.5.3, 1.9.3].
Lifestyle Factors: Avoid alcohol and discuss any over-the-counter medications (especially NSAIDs) with your doctor, as they can interact with this combination [1.2.5, 1.8.1].

The Challenge of Managing High Blood Pressure

Hypertension, or high blood pressure, is a widespread condition that significantly increases the risk for heart disease, stroke, and kidney failure [1.8.3]. While many medications are available, achieving blood pressure goals can be challenging. Often, more than 75% of patients require more than one type of medication, a strategy known as combination therapy [1.6.2]. This approach can be more effective and sometimes lead to fewer side effects compared to using a high dose of a single agent [1.5.4]. Among the many possible combinations, doctors may consider prescribing valsartan and hydralazine together for specific patients.

Understanding Valsartan: An Angiotensin II Receptor Blocker (ARB)

Valsartan belongs to a class of drugs called Angiotensin II Receptor Blockers, or ARBs [1.3.2]. It works by blocking the effects of angiotensin II, a natural substance in the body that causes blood vessels to tighten and narrow [1.3.1]. By inhibiting this substance, valsartan allows blood vessels to relax and widen. This action lowers blood pressure, making it easier for the heart to pump blood [1.8.4].

Valsartan is FDA-approved to treat:

High blood pressure in adults and children (over 1 year old) [1.8.3]
Heart failure in adults [1.8.3]
To improve survival after a heart attack [1.8.3]

Common side effects can include dizziness, headache, and fatigue [1.3.1]. A more serious risk is the potential for high blood potassium levels (hyperkalemia) and impaired kidney function, which require monitoring by a healthcare provider [1.3.1]. Valsartan should not be used during pregnancy as it can cause harm or death to the developing fetus [1.8.3].

Understanding Hydralazine: A Direct-Acting Vasodilator

Hydralazine works differently. It is a direct-acting vasodilator, meaning it acts directly on the smooth muscles in the walls of arterioles (small arteries), causing them to relax and widen [1.4.2]. This decreases peripheral resistance, which in turn lowers blood pressure [1.4.2]. The exact molecular mechanism is not fully understood but it leads to a potent blood pressure-lowering effect [1.4.1].

Hydralazine is used to treat:

High blood pressure, often in combination with other drugs [1.9.4]
Hypertensive emergencies, especially in pregnancy [1.4.1]
Heart failure, particularly in combination with isosorbide dinitrate for people of African descent [1.4.2]

Because it works so directly, hydralazine can cause a reflex sympathetic stimulation, leading to side effects like a rapid heart rate (tachycardia) and palpitations [1.4.2]. Other common side effects include headache and nausea [1.4.2]. Long-term, high-dose use is associated with a risk of developing a drug-induced lupus-like syndrome [1.9.3].

Rationale for Combining Valsartan and Hydralazine

Prescribing valsartan and hydralazine together is a strategic decision made by a healthcare provider to tackle high blood pressure from two different angles. Valsartan blocks the renin-angiotensin system, a key hormonal pathway in blood pressure regulation, while hydralazine provides direct vasodilation [1.3.2, 1.4.2].

The primary interaction between these two drugs is their additive effect on lowering blood pressure [1.2.1]. This can be highly beneficial for patients with resistant hypertension who haven't responded to other treatments. However, it also means there is a higher risk of hypotension (blood pressure that is too low) [1.5.2].

Close monitoring by a doctor is essential when these drugs are used together. This includes regular checks of blood pressure and heart rate [1.10.3]. The doctor may need to adjust the dosages of one or both medications to find the right balance that effectively controls blood pressure without causing unwanted side effects like dizziness, lightheadedness, or fainting [1.5.2].

Comparison Table: Valsartan vs. Hydralazine


Feature	Valsartan	Hydralazine
Drug Class	Angiotensin II Receptor Blocker (ARB) [1.11.2]	Vasodilator [1.11.2]
Mechanism	Blocks angiotensin II from tightening blood vessels [1.3.1]	Directly relaxes the muscles in artery walls [1.4.2]
Primary Uses	Hypertension, Heart Failure, Post-Heart Attack [1.11.2]	Hypertension, Hypertensive Emergency, Heart Failure [1.11.2]
Common Side Effects	Dizziness, headache, high potassium levels [1.3.1]	Headache, rapid heart rate, palpitations, nausea [1.4.2]
Dosing Frequency	Typically once daily [1.8.2]	Usually two to four times daily [1.9.4]
Key Precaution	Do not use if pregnant [1.8.3]	Risk of drug-induced lupus-like syndrome [1.9.3]

Living with Combination Therapy

Patients prescribed both valsartan and hydralazine must be diligent about following their doctor's instructions. It's crucial to take the medications as prescribed and not to stop them abruptly, as this could cause a dangerous spike in blood pressure [1.2.1].

Key patient counseling points include:

Monitoring: Regularly check your blood pressure at home as directed by your doctor [1.8.1].
Side Effects: Be aware of symptoms of low blood pressure, such as dizziness, lightheadedness, or fainting, especially when getting up from a sitting or lying position [1.10.1].
Communication: Report any side effects to your healthcare provider. This includes dizziness, persistent headache, rapid heartbeat, or unexplained joint pain and fever [1.5.2, 1.9.4].
Other Medications: Inform your doctor and pharmacist about all other medications you use, including over-the-counter drugs like NSAIDs (e.g., ibuprofen), supplements, and herbal products [1.8.1, 1.9.1].
Lifestyle: Avoid alcohol, as it can increase the blood pressure-lowering effects of both medications [1.2.5]. Stay well-hydrated, as dehydration can lead to a drop in blood pressure [1.8.2].

Conclusion

Taking valsartan and hydralazine together is a valid therapeutic option for managing difficult-to-control hypertension and certain cases of heart failure. By combining an ARB and a direct vasodilator, physicians can achieve greater blood pressure reduction. However, this increased efficacy comes with a heightened need for careful medical supervision to manage the risk of hypotension and other potential side effects. Patients on this combination therapy must maintain open communication with their healthcare team and adhere closely to monitoring instructions to ensure the treatment is both safe and effective.

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Frequently Asked Questions

A doctor may prescribe this combination for resistant hypertension, where blood pressure is not adequately controlled by other medications, or for specific cases of heart failure. The two drugs work in different ways to relax blood vessels and lower blood pressure effectively [1.5.3, 1.4.2].

The biggest risk is hypotension (blood pressure becoming too low), which can cause dizziness, lightheadedness, and fainting [1.5.2]. Both drugs lower blood pressure, and their combined effect can be potent. Close monitoring is required [1.10.3].

Valsartan is an Angiotensin II Receptor Blocker (ARB) that prevents a hormone from constricting blood vessels [1.3.1]. Hydralazine is a direct vasodilator that acts on the smooth muscle of the arteries to make them relax [1.4.2].

You should avoid or limit alcohol. Alcohol can add to the blood pressure-lowering effects of both medications, increasing the risk of dizziness and fainting [1.2.5].

Watch for symptoms of low blood pressure like dizziness, weakness, or fainting. Also be aware of side effects specific to each drug, such as rapid heart rate (from hydralazine) or potential for high potassium (from valsartan) [1.5.2, 1.3.1, 1.4.2].

No, you should never stop taking any blood pressure medication, including valsartan or hydralazine, without first talking to your doctor. Abruptly stopping can cause a rapid and dangerous increase in blood pressure [1.2.1].

Your doctor will likely require more frequent monitoring of your blood pressure and heart rate, especially when starting the therapy or adjusting doses, to ensure the combination is safe and effective for you [1.10.3].