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Sleeping pills & minor tranquillisers A-Z

Provides detailed information on all sleeping pills & minor tranquillisers currently available in the UK.

diphenhydramine

Diphenhydramine is an antihistamine sometimes used as a sleeping pill.

It is an ingredient in some over-the-counter cold and flu medicines and sleep aids, under trade names such as Benylin, Nytol and Boots Sleapeaze.

You can find detailed information about this drug in the official Patient Information Leaflet (PIL). This includes information on what the medication is for, how to take it, possible side effects and safety information.

This leaflet should come with your medication, usually inside the box. Or you can download a PDF version of the PIL for your medication:

Some drugs come in different forms, such as tablets or liquid. There may be a separate PIL for each form of the drug, as well as for different doses. You should look at the PIL for the form and dose you have been prescribed.

You can also search these websites for your specific drug to find further information and PILs:

If you have any questions about your medication you can:

  • talk to your doctor, or any healthcare professional who prescribes your medication
  • speak to someone at a pharmacy
  • contact NHS 111 if you live in England
  • contact NHS 111 or NHS Direct (0845 46 47) if you live in Wales.

If you experience any side effects from your drug, you can report them to the MHRA via their Yellow Card scheme. This scheme allows the MHRA to collect information about which drugs cause which side effects and how common they are. This lets drug manufacturers give more accurate information about their medication.

Even though this drug is available without a prescription, it's a good idea to check with the pharmacist that it's suitable for you before buying it.

See our page on what you need to know before taking any medication for a list of issues you might want to go through with them. Most high street pharmacists have a private consulting room you can ask to use if you don't feel comfortable discussing these issues over the counter.

More information about sleeping pills and minor tranquillisers

Our pages on sleeping pills and minor tranquillisers have lots more information about this type of medication. This includes how they work, what they are prescribed for and what to know before taking them. It also covers their side effects and withdrawal effects.

These pages may also help:

  • About psychiatric medication. See our pages on psychiatric medication for information on what you should know before taking any psychiatric drug, receiving the right medication for you, and your right to refuse medication.
  • About side effects. See our page on coping with side effects for information on what to do if you experience a side effect.
  • About coming off medication. See our pages on coming off psychiatric drugs for information on making your decision to come off medication, planning withdrawal and withdrawal symptoms. 
  • About accessing treatment. See our pages on seeking help for a mental health problem for more information on getting treatment for your mental health.
  • About interactions with recreational drugs and alcohol. See our page on recreational drugs and medication for information about how prescribed medications and other drugs can interact. 

This information was published in April 2021. We will revise it in 2024.

References are available on request. If you would like to reproduce any of this information, see our page on permissions and licensing.

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