DON’T use antihistamines to help you sleep.

As a Tuesday paper out of McMaster University published in the Canadian Medical Association Journal noted, “Antihistamines are among the most commonly and incorrectly used medicines worldwide.”

While antihistamines are recommended to address the symptoms of hay fever and outbreaks of hives, they have other off label-uses, including for insomnia, according to the paper. Benadryl, ZzzQuil, Tylenol PM, Dramamine, Unisom, and many other over-the-counter (OTC) sleep medications include antihistamines. The recent McMaster University paper made a case for avoiding the use of these medications for treating anything other than hay fever or hives.

The American Academy of Sleep Medicine (AASM) officially recommends against treating chronic insomnia with common OTC antihistamine-based medications due to a lack of evidence for their efficacy or safety. “There are definite concerns about their risks,” said Suzanne Bertisch, an assistant professor of medicine at Harvard Medical School, in an article on the university website. Taking antihistamines for sleep can cause adverse side effects.

The McMaster University paper noted that antihistamines can affect cognitive functions, such as school or work performance, and an overdose can even lead to death. According to the Baylor College of Medicine, “Antihistamines have side effects that include altered mental state, urinary retention, and dry mouth. While these side effects are generally mild and well tolerated in young patients without other medical problems, they can pose a risk, especially for the elderly.”

Additionally, the antihistamines you’re taking to improve your sleep may ultimately have the opposite effect. “Use of antihistamines can lead to sleepwalking and other parasomnias. That can definitely occur with Benadryl just as with other hypnotic agents like Ambien,” assistant professor of medicine Phillip Alapat said in an article on the Baylor College of Medicine website.

Although antihistamines may help you fall asleep, the overall quality of sleep is often not very good, and the medication has its limits. “Using Benadryl or any antihistamine for sleep has no long-term benefit,” Alapat continued. “Most people develop a tolerance very quickly.”

Not all antihistamines are the same, however. The paper from McMaster University noted that first-generation antihistamines are the ones to worry about, while newer antihistamines are generally safer.

Benadryl, ZzzQuil, Tylenol PM, Dramamine, Unisom, and many OTC sleep medications contain first-generation antihistamines, while allergy medications like Zyrtec, Claritin, and Allegra, on the other hand, contain second-generation antihistamines.

The McMaster University paper noted that later-generation antihistamines are safer while also being more effective and just as affordable as first-generation antihistamines. The newer antihistamines also have fewer side effects, such as drowsiness, which means they likely would not aid sleep.

Antihistamines are also used off-label to address asthma, eczema, and coughing, but that’s not what they’re meant for. “People need to rethink what they stock in their home cabinets as allergy medicines, what hospitals keep on formulary, and what policymakers recommend. The message needs to get out,” McMaster University allergy expert and clinical scholar Derek Chu said in a statement.

(SD-Agencies)