This Is What Happens When You Take Sleep Medication for 30 Days in a Row, According to a Pharmacist


Many of us reach for medication to help us fall asleep. With numerous over-the-counter (OTC) options available, it's tempting to pop a pill if you're tossing and turning at night. But is it safe to take these drugs and supplements for weeks at a time?

Best Life asked Shawn Patrick Griffin, PharmD, an assistant clinical professor at the University of California, Irvine, to weigh in on what happens to our bodies when we take sleep aids for a month. Read on to find out what he (and other healthcare professionals) had to say.

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You might experience dry mouth and headaches.

Griffin says people who take diphenhydramine (sold under the brand name Benadryl, among others) to help them fall asleep might experience a host of unpleasant issues after extended use. "Diphenhydramine can cause dry mouth," he explains, adding that the drug can also cause "blurred vision… confusion, [and] dizziness."

Doxylamine (one brand name: Unisom) is another popular sleep medication that can cause dry mouth and dizziness. "The outcomes with doxylamine are very similar to that of diphenhydramine," says Griffin. Verywell Health lists dizziness, headaches, and confusion as common side effects, noting that "Unisom is intended as a temporary sleep aid and should not be taken for more than two weeks."

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You may have difficulty driving.
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While drowsiness is great when you're trying to fall asleep, several sleep medications can result in next-day drowsiness as well, which can be dangerous if you need to drive. According to the Mayo Clinic, "[Some] sleep aids available without a prescription can leave you feeling groggy and unwell the next day. This is the so-called hangover effect."

Griffin confirms that "increased risk for next-day drowsiness" is present for those taking doxylamine, diphenhydramine, and even melatonin, supplements which contain the hormone which affects our sleep/wake cycles in the brain.

You could experience constipation.

Constipation is a common—and very unpleasant—side effect from certain sleep medications is constipation. MedicalNewsToday lists constipation as a potential outcome of regular Benadryl use, saying, "If you have constipation, talk with your doctor or pharmacist about other medication options."

You might build up a tolerance.

Both diphenhydramine and doxylamine may become less effective over time, as your body builds up a tolerance to the medication. According to the CDC, "OTC sleeping aids may lose their effectiveness over time." And Verywell Health explains that "Doxylamine is a non-habit forming medication. However, you can develop a tolerance to it, which means you'll have to take more of it over time to get the same effect. This can lead to an increased risk of other side effects."

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Your other medications may be impacted.
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MedicalNewsToday provides a long list of medications that Benadryl might interfere with, including other anticholinergics and antihistamines, antidepressants, opioids, and antipsychotics. They also caution that, "[d]ifferent drug interactions can cause different effects. For instance, some can interfere with how well a drug works, while others can cause increased side effects. If you take other medications, talk with your pharmacist before taking Benadryl. Your pharmacist can help you avoid potential interactions."

According to Griffin, the side effects of sleep medication may also be more pronounced in people who take "certain antidepressants and pain medications."

You could develop liver problems.

We asked Griffin about valerian supplements, which are made from the flowering valerian plant and are a popular choice among herbal sleep aids.

"There is limited evidence about the efficacy and safety of valerian as a sleep aid," Griffin replied. "As a result, it is difficult to make recommendations on how much valerian should be used or can be used safely. However," he went on, "at high doses, valerian may damage the liver and should be used cautiously especially in anyone with liver disease. Like melatonin, valerian is considered a supplement, meaning there is much less regulation related to the manufacturing of these products."

Some sleep aids seem to have fewer side effects than others.
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"There are few side effects with melatonin," explains Griffin. "However, there is a general lack of long-term research, making this question difficult to answer definitively… One thing to keep in mind is that melatonin is a supplement, meaning there is much less regulation and oversight surrounding exactly how and where these products are manufactured."

The Mayo Clinic describes valerian supplements as a similarly mixed bag. "Side effects appear to be mild," they explain, adding that "a few studies indicate some therapeutic benefit, [but] other studies haven't found the same benefits" and like melatonin, more research is needed to determine the scope of how effective this supplement really is.


If you find yourself taking sleeping pills every night, talk to your healthcare provider.
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"Take it one day at a time," the Mayo Clinic advises, cautioning that OTC sleeping medications "might be a temporary solution for sleep problems," but are "not intended for long-term use."

Rather than taking any brand of sleep aid or drowsiness-inducing drug for 30 days or more, let your healthcare provider know that you're having trouble sleeping, and let them help you work out a safe care plan.

Best Life offers the most up-to-date information from top experts, new research, and health agencies, but our content is not meant to be a substitute for professional guidance. When it comes to the medication you're taking or any other health questions you have, always consult your healthcare provider directly.