If You Notice This After Taking Benadryl, Call Your Doctor

Pay attention to the clear signs that you've taken too much.

Benadryl is a popular over-the-counter medication for more than one reason: Most allergy sufferers know the quick relief that Benadryl provides from symptoms like a runny nose and sneezing, and Benadryl is also widely used as a sleep aide, since one of its most notable side effects is drowsiness. But as reliable as Benadryl can be, taking it daily for allergies or nightly for sleep problems might not be the best course of action for everyone—especially if you're taking a little more than you should be. Read on to find out what you should keep an eye out for after taking Benadryl.

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If you notice increased side effects after taking Benadryl, call your doctor.

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There is such a thing as too much Benadryl. Chet Tharpe, MD, the medical director at Curex, says that the "more Benadryl one takes, the higher likelihood one may encounter" certain side effects, including blurred vision, dry mouth, urinary retention, increased heart rate, nausea, constipation, drowsiness, fatigue, agitation, poor concentration, and impaired memory.

Unfortunately, people end up taking more Benadryl than they should, because it is "very short-acting and wears off within four to six hours," says Neeta Ogden, MD, an allergist and medical advisor for Curex. According to Ogden, Benadryl overuse is especially common during peak allergy seasons.

"If your symptoms are not controlled, or if you are experiencing side effects from the medication, please contact your primary care provider or local pharmacist for recommendations," says Mitchell Howard, PharmD, a clinical assistant professor at the University of Toledo College of Pharmacy and Pharmaceutical Sciences.

The amount of Benadryl you should take depends on a few factors.

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Clara Lawson, MD, a medical doctor working with USA Hemp, says the proper amount of Benadryl someone takes each day depends on a few factors, like your age and the particular type of Benadryl you are taking, as it comes in various forms including pills, creams, and sprays. On average, she says that adults and children over the age of 12 should not take more than 25 to 50 milligrams of Benadryl every five to six hours, while kids below that age shouldn't take more than 12 to 25 milligrams of Benadryl every five to six hours. According to Howard, the maximum daily dose over the course of a day, if needed, is 300 milligrams.

"Taking Benadryl orally shouldn't be more than five to six times a day," Lawson explains. "Whereas, Benadryl topical products including creams, gels, and sprays shouldn't be applied over the skin more than four times a day."

She adds, "Generally, you should take a small dose and if you are unsure about the right dosage according to your symptoms, consult a doctor or a pharmacist."

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Overusing Benadryl may also be linked to serious health consequences.

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Frequent use of Benadryl over time has also been linked to an increased possibility of developing dementia, warns Stephen George, MD, a medical doctor specialized in gynecology, immunology, pediatrics, and internal medicine. But the research is not concrete. A 2015 study published in JAMA Internal Medicine observed people taking anticholinergic medication every day for more than three years and found that they had a significantly higher risk of developing dementia compared to those who never took anticholinergic medication. But this study did not break down and report on individual forms of the medication, like Benadryl.

Another 2016 study, published in JAMA Neurology, also showed that people taking anticholinergic medications had signs of brain shrinkage on MRI scans and lower mental test scores, but didn't determine which specific medications were linked to these results either. "While the research has not found a definitive link between Benadryl and dementia, the findings do raise a cautionary flag," GoodRx explains.

Experts say there are many better options than overdoing it with Benadryl.

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This doesn't mean allergy sufferers need to suffer in silence, however. Ogden says that there are plenty of medications you can use for allergies, and it would be good to start with a 24-hour second generation antihistamine like Zyrtec, Allegra, Xyzal, or Claritin, as well as trying nose sprays and eye drops to treat allergy symptoms. Howard notes that these second generation antihistamines are "typically taken once daily, have less drowsiness, and no anticholinergic side effects, which is why they are recommended more often for your typical daily or seasonal allergies." He also recommends trying a different medication if one doesn't work for you.

"Whichever medication you use to relieve your symptoms, it should not be overused at all," Lawson cautions. "And if your condition isn't getting better after taking over-the-counter medicine, don't increase its dosage and rather, see a doctor as soon as possible."

RELATED: Never Use This Common Medication for Longer Than a Week, Experts Warn.

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