Is It Safe To Take Benadryl Every Night?

You're lying in bed, eyes wide open, counting the hours of sleep you'll get if you could just fall asleep right now. Frustrated, you find yourself looking through your medicine cabinet to see if anything will help. You swallow some Benadryl and fall asleep quickly. The next night, you find yourself taking it again so you can sleep, but wonder if you should.

Benadryl is an over-the-counter antihistamine. While Benadryl is the brand name, the name of the medication is diphenhydramine. According to Drugs.com, Benadryl blocks histamine receptors in the brain and is used to treat allergies, sleeplessness, motion sickness, and Parkinson's disease symptoms. The usual dose is 50 milligrams, taken orally, but might be lower for the elderly. Benadryl works fast and peaks about an hour after taking it, lasting 4-6 hours. It can interact with other medications, most commonly opioids, monoamine oxidase inhibitors (MAOIs), benzodiazepines, sedatives, allergy medications, and anything that contains diphenhydramine. Talk to your doctor to see if it's safe for you to take.

If you have trouble getting to sleep, the sleepiness side effect of Benadryl can help you dose off, but is it safe to take it every night?

Some studies have researched the long-term effects of taking an anticholinergic, and although Benadryl is an antihistamine, it does have anticholinergic effects (per UpToDate). Acetylcholine is a neurotransmitter essential for thinking, short-term memory, and other brain functions. 

A 2015 study published in JAMA Internal Medicine took a closer look at the impact of anticholinergic medications. It included 3,434 participants aged 65 and older who did not have dementia when entering the study. Researchers followed the participants for 7 years. Those who took anticholinergic medications for 3 or more years had an increased risk of dementia and Alzheimer's disease. 

A usual dose of Benadryl — 25 to 50 milligrams — can last up to 6 hours, but will stay in your body for longer. This may cause you to feel a bit foggy the following day (via Self). The other side effects of Benadryl you may experience include everything from dry mouth to vomiting, according to the U.S. National Institutes of Health. See your doctor if you experience problems with your vision, trouble urinating, or painful urination. 

Self also notes that you can build up a tolerance to Benadryl quickly, meaning it will take a higher dosage to continue to work. However, higher doses are dangerous, and the side effects are worse. The bottom line is that Benadryl is acceptable to use occasionally, but should not be used long term. If you are having trouble sleeping, see your doctor for help.