"PM" Sleep Aids After 50: What's in the Box and Why Experts Advise Caution

On a night when sleep won’t come, a box marked “sleep aid,” “nighttime” or “PM” is easy to reach for. Turn it over, and the active ingredient is usually diphenhydramine or doxylamine. Both are first-generation antihistamines, the same family as older allergy pills. Here is what experts say about using them for sleep, especially after 50.

What the sleep guideline says

The American Academy of Sleep Medicine’s guideline on medicines for chronic insomnia suggests that clinicians not use diphenhydramine to treat trouble falling or staying asleep.¹ The guideline rates this as a weak recommendation. The same guideline also suggests against melatonin for chronic insomnia.¹

What geriatrics experts say

The American Geriatrics Society’s Beers Criteria list medicines that older adults should generally avoid. The 2023 update says to avoid first-generation antihistamines, including diphenhydramine and doxylamine. It describes them as strongly anticholinergic, cleared more slowly with age, and less effective as a sleep aid over time as tolerance builds.²

The Beers Criteria list risks that include confusion, dry mouth and constipation. They link cumulative use of anticholinergic medicines with a higher risk of falls, delirium and dementia.² MedlinePlus³ says diphenhydramine shouldn’t be used in older adults except for serious allergic reactions, because other medicines are safer and more effective, and advises adults 65 and older to discuss risks and benefits with their doctor.³

What the label tells you

The standard Drug Facts for a diphenhydramine sleep aid say:⁴

• Don’t combine it with any other product containing diphenhydramine, even one you put on your skin. Some “PM” pain relievers and allergy products contain it too. MedlinePlus³ warns that doubling up could lead to an overdose.³
• Ask a doctor first if you have glaucoma or a breathing problem such as emphysema or chronic bronchitis.
• Ask first if you take sedatives or tranquilizers, and avoid alcohol while using it.
• Stop and ask a doctor if sleeplessness lasts more than 2 weeks. The label notes that insomnia may be a sign of a serious underlying illness.

MedlinePlus³ advises calling a doctor about vision problems or difficult or painful urination while taking diphenhydramine.³ If you already have bladder emptying problems or constipation, that’s worth knowing before you take it.

Ask what’s keeping you up

Hot flashes, night sweats, pain, getting up to pee, low mood and sleep apnea can all break up sleep, and each has its own treatment. If you need help most nights, a visit is likely to do more than another box. Our article on insomnia and CBT-I explains a structured approach that doesn’t rely on pills.

Try: “I’ve been taking an over-the-counter sleep aid most nights. Is it safe with my other medicines, and what else could help me sleep?”

Bring every product you take, including “PM” pain relievers, to a pharmacist for a quick check.

Did I Do That in My Sleep? includes a 14-Night Lights-Out Record and a Visit Brief. Use them to log what wakes you, what you take and how you feel the next day, then bring the record to your visit. See the book.