Is diphenhydramine (Benadryl) suitable for treating insomnia?

From the Guidelines

Diphenhydramine (Benadryl) is not recommended as a first-line treatment for insomnia, especially for long-term use. While it can help with occasional sleeplessness due to its sedating antihistamine properties, typically at doses of 25-50mg taken 30 minutes before bedtime, it should only be used short-term (a few days) and intermittently 1. The medication works by blocking histamine receptors in the brain, which produces drowsiness, but it can lead to tolerance within just a few days, making it less effective over time.

Some key points to consider:

• Side effects include morning grogginess, dry mouth, blurred vision, urinary retention, and constipation.
• In older adults, diphenhydramine can increase the risk of confusion, dizziness, and falls.
• For persistent insomnia, better approaches include cognitive behavioral therapy for insomnia (CBT-I), improving sleep hygiene practices, and consulting a healthcare provider who might recommend more appropriate sleep medications if necessary.
• Anyone with chronic sleep problems should address the underlying causes rather than relying on over-the-counter sleep aids.

It's also worth noting that the American College of Physicians recommends that clinicians use a shared decision-making approach, including a discussion of the benefits, harms, and costs of short-term use of medications, to decide whether to add pharmacological therapy in adults with chronic insomnia disorder in whom cognitive behavioral therapy for insomnia (CBT-I) alone was unsuccessful 1. Additionally, the 2019 U.S. Department of Veterans Affairs and U.S. Department of Defense clinical practice guidelines advise against the use of benzodiazepines, trazodone, antihistamines, and antipsychotics for the treatment of chronic insomnia disorder due to their adverse effect profiles and limited evidence of efficacy 1.

From the FDA Drug Label

Warnings Do not use • to make a child sleepy • with any other product containing diphenhydramine, even one used on skin

When using this product • marked drowsiness may occur • avoid alcoholic drinks • alcohol, sedatives, and traquilizers may increase drowsiness

Diphenhydramine is not explicitly approved for treating insomnia. The label warns against using it to make a child sleepy and mentions that marked drowsiness may occur as a side effect. However, it does not provide direct support for its use as a treatment for insomnia.

• The FDA drug label does not answer the question.

From the Research

Diphenhydramine for Sleep

• Diphenhydramine, also known as Benadryl, is sometimes used as a sleep aid, but its suitability for treating insomnia is a topic of discussion among healthcare professionals 2, 3, 4, 5, 6.
• Studies have shown that diphenhydramine can be effective in improving sleep measures, such as reducing the number of awakenings and increasing sedation 4, 5, 6.
• However, diphenhydramine is not without risks, particularly in the elderly population, where it can cause cognitive impairment, increased risk of falls, and other adverse effects 2, 3, 6.
• The American Geriatrics Society recommends avoiding diphenhydramine in older adults due to its potential for adverse effects 2.
• Alternative sleep aids, such as melatonin, may be a safer and more effective option for treating insomnia in older adults 3, 4.

Efficacy and Safety of Diphenhydramine

• A systematic review of over-the-counter sleep aids found that diphenhydramine had a statistically significant increase in sedation and decrease in number of awakenings, but its safety profile was not significantly different from other products 4.
• A double-blind study found that diphenhydramine was effective in treating insomnia in psychiatric patients, with a significant improvement in sleep quality and no severe side effects 5.
• A randomized, controlled trial found that temazepam was more effective than diphenhydramine in improving sleep quality, but diphenhydramine was associated with fewer adverse effects 6.

Recommendations for Use

• Diphenhydramine should be used with caution in older adults, and only when other treatment options have been exhausted 2, 3.
• The dosage of diphenhydramine should be carefully considered, as higher doses may increase the risk of adverse effects 5, 6.
• Alternative sleep aids, such as melatonin, should be considered as a first-line treatment for insomnia in older adults 3, 4.