Sleep Aids: Antihistamines and Melatonin
A Guide to Common Over-The-Counter Sleep Medicines
Tossing and turning at 3AM? Staring at the ceiling after you’ve run out of sheep to count? Maybe you’ve just finished flying for 16 hours and you’re jet-lagged. We’ve all been there: for whatever reason sleep isn’t coming tonight and there’s nothing that can be done about it. Or is there? A quick trip to the local drug store can help make your next trip to dreamland easier.
Benadryl and Unisom
Drugs like Benadryl and Unisom have been around for a long time and their effects on sleep are well documented. The active ingredients in these medicines are diphenhydramine and doxylamine respectively. These medicines belong to a wider class of drugs known as antihistamines (yes the same antihistamines that you reach for when your nose starts running). Other products on the shelf can contain antihistamines like diphenhydramine, and are often the ingredient differentiated by the “PM” part of the product name (for example Tylenol PM is just regular Tylenol with diphenhydramine added). Most antihistamines can make you drowsy (with a few exceptions like cetirizine, levocetirizine and fexofenadine)so be careful to check with the pharmacist before taking a new over-the-counter for possible drowsiness. In the case of insomnia, drowsiness is what you want and these medicines can act quickly.
Benadryl and Unisom, like all antihistamines, should be used with extreme caution in people over the age of 65. If this is your first time using an antihistamine for sleep, be aware that drowsiness can persist into the next day for some people so plan accordingly. Tolerance can develop to these medicines over time, so long-term use of these drugs is not recommended. In general these products should be used for 2–3 nights in a row, with a skipped night afterwards to see if you still need to use it. Exact dosing for these products can be found on the back of the packaging, and generally should be taken 1–2 hours before the desired bedtime. If insomnia persists after 14 days, contact your healthcare provider for further options.
Melatonin
Melatonin is a chemical that is naturally produced by the human body (specifically by the pineal gland in the brain). Melatonin’s main purpose is to regulate the sleep/awake cycles of the body, meaning that at night time the brain produces melatonin to tell your body it’s time for sleep. Conveniently, melatonin supplements are available over-the-counter and can help with sleep disorders like insomnia and circadian rhythm disorders (like jet-lag).
The usual dosage for melatonin is 2–5 mg per dose (jet-lag may require even smaller doses in the range of 0.5–2 mg). For best results it should be taken 30 minutes to 1 hour before the desired bedtime. According to the American Academy of Pediatrics melatonin is safe for short periods of time (days to weeks) but should not be used long-term. If trouble sleeping persists even after 2 weeks on melatonin speak with your healthcare provider.
In the case of jet-lag it’s suggested that melatonin has the best results when started on the first day of travel before the desired new bedtime. Melatonin is usually well tolerated by people, with nightmare’s being the most common complaint. Like antihistamines people who are newly starting melatonin should be cautious until they know how melatonin affects their bodies and their alertness.
Both antihistamines and melatonin are relatively safe and proven sleep aids available in the aisles of most pharmacies. There are specific situations where these medicines should not be used, and you should speak to your pharmacist or doctor before beginning to use one of these products.
Thank you for reading,
Stephen Wang
PharmD Candidate 2020
