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Diphenhydramine (Nytol)

Written by Healthwords's team of doctors and pharmacists based in UK | Updated: 13.02.2023 | 2 min read

Diphenhydramine (Nytol) is a medication used to treat short-term insomnia for ages 12 years and over. It belongs to a family of medications called antihistamines. It can also be found in creams, used to relieve bites and stings, and in cold and flu preparations to aid with runny and itchy noses and to aid sleep if symptoms are bothersome at night time.

How does it work?

Diphenhydramine is an antihistamine that can cause drowsiness by acting on histamine receptors in the brain. It can reduce the time taken to fall asleep but may also reduce the depth and quality of sleep. Take it 20 - 30 minutes before bedtime; its maximal effect may be experienced after 1 hour.

While diphenhydramine may help get you to sleep, the medication can reduce the quality of your sleep. The medication can cause your body to spend longer in light sleep stages rather than more restorative, deeper sleep. It is useful to help aid sleep when there are temporary disturbances to sleep, such as stress or anxiety.

How long can I take it for?

Nytol is licensed for short-term insomnia and should only be used for two weeks. This is because taking sleeping tablets for extended periods may worsen your insomnia. Over extended periods of time, your body can become dependent on sleeping tablets to help you sleep, and you may find you need a higher dose for it to work.

It is best taken sparingly and only as needed. If possible, it may be best to take breaks in-between taking sleeping tablets, for example, 2 - 3 nights a week if tolerated. Otherwise, stick to the maximum period of 2 weeks of treatment.

If you are still finding it hard to sleep or still need to take Nytol after the 2-week treatment period, talk to your doctor, who will advise you. You may also find it useful to try non-drug therapy to solve the cause of your insomnia, focusing on good sleep hygiene.

Are there any side-effects?

Common side effects include altered mental attention, dizziness, dry mouth, and blurred vision.

Do not take it if you have breathing problems, glaucoma, or an enlarged prostate. Do not drive or operate heavy machinery after taking this medication. Alcohol will enhance the effects, so avoid taking them together.

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