Is it Okay to Take Benadryl with High Blood Pressure Meds? Understanding the Risks

October 10, 2025 •

5 min read

According to the American Heart Association, nearly half of all American adults have high blood pressure, making medication safety a common concern for millions of people. When seeking allergy or cold relief, a key question arises: 'Is it okay to take Benadryl with high blood pressure meds?', and the answer is more nuanced than a simple yes or no, largely depending on the exact product and your overall health.

Quick Summary

Taking a single-ingredient Benadryl is generally considered safe with most blood pressure medications, but combination products containing decongestants must be avoided due to significant cardiovascular risks. Certain medication interactions and individual health factors warrant careful consideration and professional medical advice.

Key Points

Single-ingredient Benadryl is often safe: Benadryl (diphenhydramine) alone is generally not known to raise blood pressure and is considered safe for many individuals with hypertension, particularly if well-controlled.
Avoid decongestant combinations: Medications combining antihistamines with decongestants (like pseudoephedrine or phenylephrine) must be avoided, as decongestants can significantly increase blood pressure and heart rate.
Look for the '-D': Many combination products containing decongestants are indicated by the letter "D" in their name (e.g., Claritin-D, Zyrtec-D), and their labels must be carefully checked.
Consider non-drowsy alternatives: Second-generation antihistamines like Zyrtec (cetirizine) and Claritin (loratadine) are excellent, safe choices for managing allergies without affecting blood pressure.
Watch for certain drug interactions: Some blood pressure medications, especially specific beta-blockers like metoprolol, can have an enhanced effect when taken with Benadryl, potentially causing low blood pressure.
Consult a healthcare professional: Always speak with a doctor or pharmacist before taking any new over-the-counter medication if you have high blood pressure or other chronic conditions.

What is Benadryl and How Does It Affect the Body?

Benadryl is a brand name for the first-generation antihistamine, diphenhydramine. As an antihistamine, its primary function is to block the effects of histamine, a natural chemical released by the body during an allergic reaction. This blockage helps alleviate common allergy symptoms such as sneezing, itching, and a runny nose. However, because it is a first-generation antihistamine, diphenhydramine can cross the blood-brain barrier, leading to significant side effects like drowsiness, dizziness, and confusion.

When it comes to blood pressure, diphenhydramine itself does not typically have a major impact. Unlike decongestants, which work by constricting blood vessels, Benadryl's mechanism does not directly cause a spike in blood pressure. However, in rare cases, it can cause a slight decrease in blood pressure, especially in older adults or when interacting with other medications. This effect can potentially lead to symptoms like dizziness and an increased risk of falls.

The Critical Difference: Antihistamines vs. Decongestants

This is the most important distinction for anyone with hypertension. While Benadryl's active ingredient is an antihistamine, many over-the-counter (OTC) cold and allergy medications contain a combination of ingredients, including decongestants.

Why Decongestants are Dangerous with High Blood Pressure

Decongestants, such as pseudoephedrine and phenylephrine, work by narrowing blood vessels throughout the body to reduce swelling and clear nasal congestion. This constriction, however, also raises blood pressure and heart rate, which can counteract the effect of your high blood pressure medication and pose a serious health risk. For this reason, individuals with high blood pressure should be very cautious and generally avoid products that contain decongestants.

How to Identify Combination Medications

Often, combination products designed to treat both allergies and congestion will have a “-D” added to the brand name, such as Allegra-D or Claritin-D. Always read the active ingredients list carefully on any OTC product to ensure it does not contain pseudoephedrine or phenylephrine.

Potential Drug Interactions with Benadryl and Blood Pressure Meds

Even with single-ingredient Benadryl, there are specific interactions to be aware of, especially with certain types of blood pressure medication. While there is no known interaction with many common antihypertensives like lisinopril or candesartan, some interactions can occur with other medications.

Beta-Blockers: Benadryl can increase the side effects of certain beta-blockers, such as metoprolol (Lopressor, Toprol XL), which can lead to dangerously low blood pressure and a slowed heart rate. This happens because Benadryl can slow the liver's ability to filter out the metoprolol, causing the blood pressure medication to stay in the body longer.
ACE Inhibitors: Additive effects in lowering blood pressure can occur when combining diphenhydramine with ACE inhibitors like lisinopril. This may increase the risk of dizziness, particularly when standing up quickly.
Anticholinergic Overload: Because Benadryl has anticholinergic properties, combining it with other drugs that have similar effects can heighten the risk of side effects like dry mouth, constipation, and blurred vision.
CNS Depressants: Both Benadryl and alcohol are central nervous system depressants. Taking them together significantly increases the risk of extreme drowsiness, impaired coordination, and confusion. The same is true for mixing Benadryl with sleep aids or certain antidepressants.

Safer Alternatives for Allergy Relief with High Blood Pressure

For those with high blood pressure, several safe and effective alternatives to Benadryl or decongestant combinations are available.

Oral Antihistamines:

Second-Generation Antihistamines: These are generally considered the safest oral options for people with hypertension. They are non-drowsy and do not significantly affect blood pressure. Examples include:
- Cetirizine (Zyrtec)
- Loratadine (Claritin)
- Fexofenadine (Allegra)
High Blood Pressure Formula Cold & Flu Medications: Some manufacturers offer versions of cold and flu medications specifically formulated to be safe for those with high blood pressure. These products do not contain decongestants. Look for labels that say “HBP” or “High Blood Pressure”.

Nasal Treatments:

Nasal Corticosteroid Sprays: These sprays reduce inflammation in the nasal passages without the systemic effects of oral decongestants. Safe options include fluticasone (Flonase) and triamcinolone (Nasacort).
Antihistamine Nasal Sprays: Products like azelastine (Astepro) are safe options for people with hypertension.
Saline Nasal Sprays/Rinses: These drug-free options can help clear nasal passages and thin mucus safely.

Comparison Table: Benadryl vs. Safer Alternatives for Hypertension


Feature	Benadryl (Diphenhydramine)	Second-Generation Antihistamines (Zyrtec, Claritin)	Nasal Steroid Sprays (Flonase, Nasacort)
Effect on Blood Pressure	Minimal effect, but rarely can cause a slight drop. Not recommended with some BP meds.	No significant effect on blood pressure.	No significant effect on blood pressure.
Primary Mechanism	Blocks histamine, causing systemic effects.	Blocks histamine, with fewer systemic effects.	Reduces inflammation locally in the nasal passages.
Drowsiness	High potential for drowsiness.	Non-drowsy for most people.	No drowsiness.
Combination Products	Often combined with decongestants, which are unsafe for hypertension.	Combinations with decongestants (e.g., Zyrtec-D) must be avoided.	Can be used with oral antihistamines, but decongestant sprays (Afrin) should be avoided.
Effectiveness for Allergic Rhinitis	Effective for immediate allergy symptoms.	Highly effective for daily, ongoing allergy symptoms.	Highly effective for controlling ongoing nasal inflammation and symptoms.
Best Suited For	Short-term use, emergency allergic reactions, or for sleep aid after consulting a doctor.	Managing daily or seasonal allergies.	Treating nasal congestion and inflammation from allergies.

The Critical Importance of Consulting a Healthcare Professional

Your specific health profile, the high blood pressure medication you are taking, and any other underlying conditions play a crucial role in determining which over-the-counter medications are safe for you. Before starting any new medication, it is imperative to speak with your doctor or pharmacist. They can provide personalized advice and check for potential drug interactions that may not be widely known or documented.

For instance, while Benadryl is generally safe, its potential to increase the effects of some beta-blockers illustrates the complexity of drug interactions. Your healthcare provider can determine if a temporary switch to a non-drowsy antihistamine is necessary or if monitoring your blood pressure closely is required. They can also recommend appropriate alternatives tailored to your specific needs.

Conclusion: Navigating Medications with Caution

While single-ingredient Benadryl (diphenhydramine) is typically not associated with a major increase in blood pressure and is often safe for those with controlled hypertension, the significant risk lies in combination products containing decongestants. The crucial takeaway is to be a vigilant and informed consumer. Always read labels carefully, avoid products with "-D" in the name, and opt for safer, non-drowsy alternatives if you have high blood pressure. Ultimately, the safest approach is always to consult with a healthcare professional to ensure any new medication will not interfere with your blood pressure treatment.

Frequently Asked Questions

No, single-ingredient Benadryl (diphenhydramine) is not typically known to significantly raise blood pressure. The risk comes from combination products that include decongestants.

Yes, in rare cases, and especially for older adults or those taking certain medications like metoprolol, combining Benadryl and blood pressure medication can have an additive effect, causing blood pressure to dip too low.

You should avoid any cold, flu, or allergy medication that contains a decongestant, such as pseudoephedrine or phenylephrine. These often have a "-D" in the product name.

Safe alternatives include single-ingredient, non-drowsy antihistamines like cetirizine (Zyrtec), loratadine (Claritin), and fexofenadine (Allegra). Nasal steroid sprays (e.g., Flonase) and saline sprays are also safe.

Decongestants work by constricting blood vessels to reduce swelling in the nose. This constriction affects blood vessels throughout the body, causing an increase in blood pressure and heart rate.

Yes, many manufacturers offer specific cold and flu formulas that are safe for people with high blood pressure. These products do not contain decongestants, but you should always confirm with a pharmacist.

Benadryl can increase the side effects of metoprolol, potentially leading to low blood pressure and a slowed heart rate. Consult your doctor or pharmacist for guidance before combining these two medications.

If you experience any unusual symptoms such as dizziness, headache, or a rapid heartbeat, contact your healthcare provider immediately. Always check medication labels carefully to avoid this risk in the future.

Diphenhydramine and lisinopril may have additive effects in lowering blood pressure, which can cause symptoms like dizziness. It is important to talk to your doctor about this combination.

Start by talking to your pharmacist or doctor. When shopping, prioritize single-ingredient antihistamines and avoid products with "-D" in the name. Read the active ingredients list carefully to check for decongestants.