What are the Strongest Sleeping Pills?

clinician image
Medically approved by Dr Earim Chaudry
Chief Medical Officer
iconLast updated 8th February 2022

In 30 seconds…

The strongest sleeping pills – such as benzodiazepines, “Z-drugs”, and antidepressants – tend to be available on prescription only. But over-the-counter antihistamines such as promethazine can also be used to help with insomnia. Most sleeping pills are best taken occasionally or over a short period as part of a broader strategy to improve your sleep.

The Strongest Sleeping Pills Aren’t Always the Best

Sleeplessness has many possible causes – from working shifts, to stress, to an underlying medical condition. And while treating that cause can help you get sleep better in the long-run, sometimes a sleeping pill can be the solution to a good night’s rest in the short term.

The strongest sleeping pills are generally available only on prescription, but there are a fair number of options available. Let’s take a look at what’s out there.

What are the Different Types of Sleeping Pills?

Sleeping pills (also known as “hypnotics”) fall into two broad categories: benzodiazepines and nonbenzodiazepines.


Benzodiazepines are a group of drugs that have a sedative effect. That is, they slow down the functioning of your body and brain. Taking them can help you fall asleep more easily and you’ll be less likely to wake up in the middle of the night.

They work by increasing the effects of a chemical called gamma aminobutyric acid (GABA) on your brain and your body. GABA’s job is to lessen activity in the parts of your brain that are in charge of emotions, memory, reasoning, and certain essential functions (such as breathing). It is already naturally present in your body – so the benzodiazepines just give natural GABA a bit of a boost, making you feel relaxed and sleepy.

Some examples of benzodiazepines are:

  • Estazolam (often sold as Prosom)
  • Loprazolam (brand name: Dormonoct)
  • Lormetazepam (Dormagen)
  • Nitrazepam (Mogadon)
  • Temazepam (Restoril)
  • Triazolam (Halcion)

They’re usually prescribed only to treat severe insomnia, either as a one-off dose or as a short-term treatment for up to 4 weeks. Your doctor may also recommend not taking them every day.

All this is down to the fact that the pills can get less effective over time, as your brain gets used to the drug. Plus, you may become dependent on the pills and struggle to stop using them if you take them for too long.

Benzodiazepines do come with the risk of side effects. Common ones include: dizziness and light-headedness, confusion, muscle weakness, and memory problems.

Lastly, benzodiazepines generally aren’t recommended if you have any of the following conditions:

  • Sleep apnoea (breathing problems while you’re asleep)
  • Severe lung disease
  • Severe liver disease or kidney disease
  • Severe, uncontrolled myasthenia gravis (a neuromuscular condition)

Nonbenzodiazepine Sleeping Pills

Promethazine and other antihistamines

You might have taken antihistamines before to ease allergy symptoms, if you suffer from hay fever or a pet allergy, for example. But some of these drugs also have drowsiness as a side effect, so they can be used as a sleep medication, too.

Two antihistamines that are often used to treat insomnia are:

They’re available to buy over the counter at most pharmacies.

Antihistamines can be slower to take effect than benzodiazepines and the Z-drugs, so you might not feel sleepy straight after taking them. However, promethazine is non-addictive and has been found to increase sleep time, improve sleep quality, and reduce night-time awakenings.

Find out more: Your Guide to Using Promethazine for Sleep


Melatonin is a hormone produced by the pineal gland in your brain. It’s released in the evening, as it gets dark, to encourage your body to prepare for sleep. That’s why it’s also known as the “sleep hormone”.

So, another way to improve your sleep, and to support the work of the melatonin that’s already being produced in your body, is to take this hormone as a medicine.

Melatonin is most often prescribed as a sleep medicine for older adults (55 and above) but can be effective for younger people, too. In many cases, you’ll get a 1 to 4 week course of the tablets, but they’re licensed for use for up to 13 weeks.

Find out more: Can You Buy Melatonin in the UK?

Herbal supplements

Natural sleeping pills, with rest-supporting vitamins and herbal extracts, can also help you get a better night’s sleep – sometimes alongside a medical treatment.

Key ingredients to look for include: tart cherry (a natural source of melatonin), chamomile (a traditional herbal remedy for insomnia), and Vitamin B6 (which helps reduce tiredness and fatigue).

The “Z-drugs”

The “Z-drugs” (so called because their generic names all begin with “Z”) act in a very similar way to benzodiazepines. That is, they’re also very effective at helping you go to sleep and stay asleep. But they also have some of the same problems as benzodiazepines, including addiction and dependence if you use them for a long time.

The three Z-drugs are:

  • Zolpidem (Stilnoct or Ambien)
  • Zopiclone (Zimovane)
  • Zaleplon (Sonata – but this drug is no longer licensed for use in the UK)

Common side effects include: a bitter or metallic taste in your mouth, a dry mouth, and feeling tired. There are also a few more serious potential side effects, though – such as sleepwalking, sleep-driving, and hallucinations.

If you have any of the health conditions listed above, which mean that benzodiazepines won’t be recommended for you, the Z-drugs may not be prescribed for you either.


Finally, antidepressants are drugs that are usually used to treat mental health conditions, such as depression and anxiety, but they can also help with insomnia. You’re more likely to be prescribed them as treatment for a mental health condition and insomnia, though (not sleep problems alone).

Some examples of antidepressants that can also treat insomnia are:

  • Amitriptyline
  • Doxepin (Silenor)
  • Mirtazapine (Remeron)
  • Trazodone (Molipaxin)

Which Sleeping Pills are Right for Me?

If you feel that sleeping pills might help with your sleep problems, the most important thing is to seek medical advice. Your healthcare provider will be able to work with you to establish the reason(s) behind your insomnia and create a treatment plan to tackle it.

This could include a mixture of lifestyle changes, psychological treatments (such as cognitive behavioural therapy), sleep supplements, and sleeping pills.

Key Takeaways

There’s a wide range of treatment options out there to help you if you’re having trouble sleeping, but the strongest sleeping pills tend to be available only on prescription.

In general, sleeping pills are most effective when taken occasionally or over a few weeks, as part of a broader plan to treat the underlying causes of your insomnia.


Can I Take 15mg of Zopiclone?

The usual dose of zopiclone is one 7.5mg tablet taken before you go to bed. It’s important not to take more than your prescribed dose.

Can I Take Zopiclone with Alcohol?

No, it’s not recommended. If you take zopiclone and alcohol together it can cause you to sleep too deeply, and this could lead to breathing problems and trouble waking up.

While we've ensured that everything you read on the Health Centre is medically reviewed and approved, information presented here is not intended to be a substitute for professional medical advice, diagnosis, or treatment. It should never be relied upon for specific medical advice. If you have any questions or concerns, please talk to your doctor.

Your Guide to Using Promethazine for Sleep
Promethazine is a drowsy antihistamine that is proven to help insomnia.
When to Take CBD Oil for Sleep
The research is young, but CBD oil is showing some promising possibilities when it comes to alleviating the symptoms of sleep disorders.
What Over The Counter Sleeping Pills Can You Get in the UK?
There are two ways to get sleeping pills in the UK — by prescription or over the counter.
Your Guide to Sleep Inertia
Sleep inertia is the feeling of grogginess, drowsiness, or disorientation you feel immediately after you wake up.
We use cookies to analyse data and personalise your visit, learn more in our privacy policy