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Essentials

Are Allergy Meds Safe For High Blood Pressure?

Does Benadryl raise blood pressure? Here’s how to treat your allergy symptoms while managing any pre-existing medical conditions you may have.

April 01, 2022

Does Benadryl raise blood pressure? 

Answering this question is challenging when you have a pre-existing condition to manage, like high blood pressure. When allergy season comes, you may have concerns about how your seasonal allergies will impact your health. But when you go to the pharmacy, all you see are rows of Benadryl on the shelf.

If you’re already dealing with high blood pressure, you’ll know how important it is to manage both conditions. And you want to make sure that the medications you take will be safe to combine. Below, we’ll cover the best medicine for allergies, including Benadryl and some of the common side effects.

Disclaimer: This article isn’t intended as medical advice. Always consult a doctor or healthcare professional before taking new medications.

Can allergy meds cause high blood pressure?

Allergy medications usually don’t cause high blood pressure, but with over-the-counter (OTC) medications, exceptions to this rule can exist.

Antihistamines have two varieties: first-generation and second. Each has its own set of side effects.

First-generation antihistamines are medications that cross the blood-brain barrier, creating more potent side effects, including sedative properties. Both Benadryl and NyQuil are first-generation antihistamines.

In first-generation antihistamines, some of the most common side effects are:

  • Drowsiness

  • Dizziness

  • Dry mouth

  • Dry eyes

  • Rapid heart rates

  • Constipation

  • Difficulty urinating

  • Fatigue 

Second-generation antihistamines don’t cross the blood-brain barrier, so they’re less likely to make you drowsy. When you do experience side effects, they’re often milder. Allegra, Claritin, and Zyrtec are all classified as second-generation.

For second-generation antihistamines, typical side effects include:

  • Abdominal pain

  • Coughing

  • Nausea 

  • Headaches

  • Sore throats

  • Sleepiness

For both generations of antihistamines, you should consider these things:

  • Pre-existing conditions, including hypertension, can adversely affect your allergy medication effectiveness.

  • Certain antihistamines are unsuitable if you’re pregnant or breastfeeding.

  • Some drugs are unsuitable for children under a certain age (always check the drug information on the box).

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Does Benadryl raise blood pressure or cause other side effects?

Benadryl (diphenhydramine) side effects are noted for their severity. Here are a few things to consider before taking Benadryl. 

  • While rare, diphenhydramine can cause decreased blood pressure. Decongestants like phenylephrine or pseudoephedrine can increase blood pressure, so watch out for any combination medications. Always check the label to avoid potential drug interactions.

  • Long-term use of diphenhydramine-based medication can result in an increased risk of dementia.

  • Benadryl heart arrhythmia side effects have also been purported. 

  • Avoid using Benadryl if you’re planning to drive or operate heavy machinery, as it can make you tired, increasing the risk of an accident.

Disclaimer: If you’re unsure, always ask your doctor or healthcare provider if a medication is right for you.

How can I tell if an allergy medication might impact my blood pressure?

Decongestants are the real drug to watch if you’re worried about your blood pressure, not antihistamines. Pseudoephedrine constricts blood vessels to reduce swelling and drain your sinuses, but this constriction can affect your blood pressure or heart rate. These drugs can exist in combination, so watch out for medications labeled with some variation of “cold, flu, and sinus,” as they could potentially contain antihistamines and a decongestant.

Second-generation antihistamines like Allegra, Claritin, and Zyrtec are usually safe if they’re not combined with a decongestant. The letter “D” will be added to the product name, like Claritin-D, if it includes a decongestant to treat nasal congestion. 

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Which allergy meds are safe for your heart?

1. Allegra (Fexofenadine)

Allegra is a second-generation antihistamine that treats sneezing, runny noses, and itchy eyes. Side effects include coughing, mild fevers, and stomach aches. Blood pressure side effects aren’t commonly reported, but they could emerge if you use the decongestant version, Allegra-D. 

2. Claritin (Loratadine)

Claritin, a popular brand-name second-generation antihistamine, works well for runny noses, watery eyes, and allergic reactions caused by hay fever. Side effects of Claritin can include dry mouth, headache, and dizziness. To avoid Claritin (loratadine) side effects like heart palpitations, don’t take Claritin-D.

3. Zyrtec (Cetirizine)

Zyrtec is another second-generation antihistamine used to treat runny noses, sneezing, and watery eyes. Zyrtec’s side effects can include drowsiness, tiredness, and a dry mouth. This option is safe for daily, long-term use. It shouldn’t interfere with your blood pressure medication, so long as you don’t use the decongestant version, Zyrtec-D.

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How do you take allergy meds safely?

Discuss your allergy medications with your doctor or pharmacist before taking anything new. Bring your meds with you to the doctor’s office or pharmacy, so they can examine them directly and make recommendations.

You should also consider how your age may impact specific side effects beyond blood pressure. For example, your medication could cause drowsiness and increase your risk of falling. At age 20, a fall may be easy to manage at age 20; however, if you’re over 70, even a minor fall can have serious consequences.

Finally, always follow each medication’s instruction label closely. This way, you don’t run into severe but otherwise avoidable side effects. For example, nasal sprays should only be used short-term, as they can cause damage to the nasal passageway over a long period. 

5 ways to mitigate your allergies

If you want to skip allergy meds entirely or make your medication more effective:

  • Ensure your living area has a decent air filtration system to keep out external allergens, like pollen or pollution. This will provide some allergy relief, and reduce your need for daily antihistamines. 

  • Keep your house clean to reduce the spread of allergens. Wash the dishes and clean the kitchen to cut back on mold, dust hard surfaces, and frequently wash bedding. 

  • If you have young children, maintaining a clean nursery can keep dust and allergens at bay. 

  • Run a dehumidifier in your house to remove excess moisture that contributes to mold.

  • Adjust your diet to include healthy foods like french onion soup to boost your immune system and its response to allergens. Some foods that will help with this process are honey, citrus fruits, and onions.

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