What are the side effects of taking benadryl every night

For occasional use, there are many relatively harmless sleep medicines and supplements—except for certain groups

Having trouble falling and staying asleep? You’re not alone. Some 50-70 million Americans have sleep disorders that can keep them tossing and turning at night, according to the American Sleep Association. And many of these sleep-seekers reach for over-the-counter (OTC) sleep aids like antihistamines and herbal supplements to help them get the shut-eye they need. 

Over-the-counter sleep aids are a booming business, raking in over $400 million annually in this country. Estimates vary on how many people take these medications and supplements, but use does seem to rise with age. That’s not surprising, seeing as older adults generally encounter more sleep problems than younger ones. One study, for example, suggests that 10% of adults aged 18-45 use OTC sleep aids, and of the 6.3 million Americans over 65 who report sleep difficulties, 17.5% use them.

Most over-the-counter options are considered safe when used occasionally. But when taken night after night, trouble can mount. Many of these products produce side effects, can interact with other medications you take, and may even stop working if you take them long term. 

So, what’s worth taking? And how often can you safely use it? We’ve talked to the experts about it, so you don’t have to lose sleep over it.

What are over-the-counter sleep aids?

In a SingleCare sleep survey, 44% of respondents reported taking sleep aids. Over-the-counter sleep aids were the most common. Over-the-counter sleep aids generally fall into two categories: nonprescription sleep medications and natural, dietary supplements. Of the survey takers who reported taking sleep aids, 25% took nonprescription sleep medications and 20% took natural, dietary supplements.

Nonprescription sleep medications

The active ingredient in many nonprescription medications used as sleep aids is an antihistamine, particularly diphenhydramine and doxylamine succinate. Histamine is a chemical the body produces that helps you feel awake. Antihistamines, which are often used in allergy medications, help block that chemical, so you feel drowsy. Some of these antihistamine-containing products used as sleep aids include:

• Benadryl
• ZzzQuil
• Nytol
• Unisom SleepTabs and SleepGels
• Advil PM (which also contains the anti-inflammatory ibuprofen)
• Tylenol PM (which also contains the pain reliever acetaminophen)
• Excedrin PM (which also contains acetaminophen and aspirin)

Natural sleep aids

There are a variety of herbal and dietary supplements that people take for sleep. These include: melatonin, valerian root, and chamomile.

Melatonin

Your body has a natural circadian rhythm that helps regulate your sleep-wake cycle. In response to light, your body becomes more alert. And as daylight wanes and night creeps in, your body produces melatonin, a hormone made by the pineal gland that helps promote sleep. 

Research published in the journal Plos One found that melatonin helped study subjects fall asleep seven minutes sooner than those not taking the supplement and sleep eight minutes longer while also improving their sleep quality.

But melatonin—which seems to work best in those who have disruptions to their circadian rhythms, for example those who are shift workers or who are experiencing jet lag—is not a magic bullet. Its effects are modest, and experts caution that taking more is not necessarily better. “We’re not exactly sure how melatonin dosing should work,” says Philip Alapat, MD, an assistant professor of medicine-pulmonary at Baylor College of Medicine in Houston. “But taking higher and higher doses expecting it to yield sleepiness is a common misunderstanding.” For most adults, a starting dosage is 1 mg to 2 mg, with a maximum daily dosage of 5 mg (or up to 10mg under a healthcare provider’s supervision).

RELATED: A melatonin dosage guide 

Short-term use of melatonin to combat sleeplessness is considered safe for most people, but there are some who should proceed with caution. “Although melatonin is safe to use in younger children, use in adolescents is controversial because of possible hormonal effects on sexual development,” says Craig Kimble, Pharm.D., an associate professor at the Marshall University School of Pharmacy. “Any use in children in or around the age of puberty should be discussed first with a primary care provider.”

Dr. Kimble also adds that melatonin should not be used in pregnant and lactating women or people with migraine, psychological conditions, or in cancer treatment. “Patients should discuss melatonin with their oncologists or provider before any use,” he suggests.

Valerian root

Valerian root is an herb that’s been touted for its medicinal properties for centuries. It’s thought that the root helps promote sleep by interfering with the breakdown of the neurotransmitter gamma-aminobutyric acid (GABA), a brain chemical that helps you feel calm and relaxed.

Most studies looking at valerian root and sleep are inconclusive. While some have shown that users fall asleep more quickly (one study showed they fell asleep about seven minutes faster than nonusers, though researchers didn’t believe that this finding was clinically significant) and felt they had improved sleep, others have found no effect. What’s more, many of the studies include small sample sizes and use different sources and amounts of valerian, so it’s hard to draw definitive conclusions.

Chamomile 

Chamomile is an herb that may play a role in sleep due to its chemical compounds that bind to benzodiazepine and GABA receptors. But studies examining the sleep-inducing effects of chamomile—in tea or extract form—have been mixed. In one study involving elderly subjects, those receiving capsules containing chamomile extract twice a day for 28 days reported better sleep quality than those in the control group. Yet other studies show that chamomile does not significantly improve things like sleep quality and the total time spent asleep.

The bottom line: If you want to use natural sleep aids, weigh your risks. Manufacturers of dietary and herbal supplements don’t need to meet the same Food and Drug Administration’s (FDA) safety and effectiveness standards that drugs must meet. That means there can be wide variability in the amount and quality of ingredients used. In one study analyzing the contents of melatonin supplements, for example, it was found that the amount of melatonin in the product ranged from -83% to over 478% of what was stated on the label.

Is it safe to take an antihistamine for sleep every night?

While antihistamines have been around for decades, there isn’t a lot of good data supporting their use in treating sleep problems. Research has found that they are only minimally effective in getting people to sleep, can affect the amount of good-quality sleep you get and can cause next-day grogginess, along with other potential side effects, such as dry mouth, constipation, and dizziness. The latter can be particularly problematic for older individuals, increasing their risk of mental confusion and of falling.

What’s more, research published in the JAMA Internal Medicine shows that repeated use of anticholinergic medications (including some antihistamines) can increase a user’s risk of dementia.

In general, experts don’t recommend using these drugs for anything more than an occasional sleepless night.

“The antihistamine diphenhydramine [found in Benadryl] is only approved for management of short-term or temporary sleep difficulties, particularly in those people who have problems falling asleep,” Dr. Kimble says. “The data for use in long-term or chronic insomnia is poor. Patients can become tolerant to the sedative effect within days of taking it repeatedly, and it is usually not recommended for more than three days in a row. Use of diphenhydramine as a sleep aid should be limited according to the American Academy of Sleep Medicine (AASM) guidelines. For example, if the need exceeds 14 days, you should contact your physician as it may be a sign of an underlying problem.”

RELATED: More on daily antihistamines

What is the best OTC sleep aid?

For most people, virtually any of the OTC sleep aids are safe to use on a temporary basis. Some people find them effective, others not as much. But long-term use is not recommended.

“If you feel as though one of these products benefits you and you’re not encountering significant side effects, then I don’t see a concern,” says Dr. Alapat. “But these products should not be used on a regular basis.”

If you want to use one, talk to your healthcare provider and pharmacist first. This is especially true if you’re pregnant, breastfeeding, take other prescription or OTC medications, have certain medical conditions like asthma, sleep apnea, or chronic obstructive pulmonary disease and if you are 65 or older. “It’s strongly recommended that elderly patients avoid taking these OTC sleep aids, especially the ones with antihistamines,” says Dr. Alapat. Older people metabolize drugs differently than younger ones, explains Dr. Alapat, which means a drug can sometimes linger longer in their systems. And because they tend to take more medications than younger patients, drug interactions are more likely.

Other precautions to take:

• Read the dosing directions and don’t exceed what’s recommended.
• Avoid alcohol, which in and of itself can cause drowsiness.
• Don’t drive or do anything that requires focus and concentration after taking sleep aids.

And to help yourself get a good night’s sleep, with or without an OTC sleep aid, practice good sleep habits. “Often these small life changes yield the biggest benefits,” says Dr. Kimble. Some tips to try:

• Establish a regular sleep pattern. Go to bed and get up at about the same time daily, even on the weekends.
• Make the bedroom comfortable for sleeping. Avoid temperature extremes, noise, and light.
• Engage in relaxing activities before bedtime. For example, take a warm bath or read.
• Avoid stimulation at bedtime—that means shutting off the TV, your computer, and your phone.
• Stay away from certain substances. That includes caffeine, nicotine, and alcohol. All of these can keep you awake, or prevent you from having a good night’s sleep.

Last but not least, if you’re having trouble sleeping, reach out to your healthcare provider. In some cases, a physical exam can shed light on medical conditions that are interrupting your sleep (for example, sleep apnea, gastroesophageal reflux disorder, and restless leg syndrome). Your doctor can also discuss with you whether you’re a good candidate for prescription sleep medicines, such as Ambien (zolpidem) and benzodiazepines like Restoril and Halcion.

What are the side effects of long term use of Benadryl?

How long can you take Benadryl every night?

How long can you take Benadryl?

Is Benadryl OK to take everyday?