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Sominex Sleep Aid 20mg (Promethazine) - 16 Tablets

Based on 14 reviews
Out of stock
16 Tablets £4.49
8 Tablets £2.89
Laura Henderson - Medical Content Writer
Laura Henderson
Medical Content Writer
James O'Loan - CEO & Superintendent Pharmacist
James O'Loan
CEO & Superintendent Pharmacist

What are Sominex tablets?

Sominex tablets are a treatment for short-term insomnia, helping you to drop off for some restful sleep when you’re struggling with sleepless nights. It’s ideal for adults and adolescents over the age of 16 who are finding that a lack of sleep is making it more difficult for them to work, study, or focus on everyday activities. Sominex sleeping tablets make it easier for you to fall asleep, so you’ll wake up feeling refreshed and ready to face the day.

Why can’t I get to sleep?

Difficulty falling asleep, also known as insomnia, is very common and has lots of different causes. Short-term insomnia can be irritating but is usually nothing to worry about, even if the lack of proper sleep is making you grumpy and affecting your concentration. Some of the most common reasons why you may be struggling to fall asleep or stay asleep include:

  • Stress, anxiety, or depression
  • An uncomfortable bed
  • Being too hot or too cold
  • A noisy environment
  • Jet lag
  • Shift work
  • Drinking alcohol or caffeinated drinks
  • Smoking
  • Recreational drugs
  • Some medications or medical conditions

How will the promethazine in Sominex relieve my insomnia?

The active ingredient in Sominex tablets is 20mg of promethazine, an antihistamine which can make you feel sleepy. It makes you feel drowsy, helping to reduce the amount of time it takes for you to fall asleep, which is ideal if you’re struggling to drop off to sleep at night. Promethazine is perfect for those who are suffering from temporary insomnia, as it can help to get you back into a regular sleep cycle and relieve the effects of insomnia, such as feeling tired and grumpy or finding it difficult to concentrate.

Can I take these sleeping tablets during my pregnancy?

You should speak to your doctor or pharmacist before taking Sominex during your pregnancy. You should typically avoid taking any unnecessary medications when you’re pregnant so you should only take this product if your doctor or pharmacist tells you to. You should not take Sominex within 2 weeks before you are due to give birth or when you’re breastfeeding. Small amounts of the active ingredient can pass into your milk, which may be harmful to your baby. We recommend making some lifestyle changes that could help to ease your insomnia before using medications during your pregnancy, for example, you could try to keep to a sleep schedule and ban any electronics, including your smartphone, from the bedroom.

Can I drive after taking promethazine?

The promethazine in Sominex tablets is intended to make you feel sleepy or drowsy and can cause dizziness or blurred vision as side effects. For this reason, you should not attempt to drive or use any tools or machinery after taking this product. Wait for any symptoms which could affect your attention or concentration to wear off before you attempt to drive again.

Can I drink alcohol while I’m taking these sleeping tablets?

You should not drink alcohol while taking Sominex sleeping tablets. Alcohol can interact with this medication, which can cause unwanted effects or make the effects of this medication stronger. For example, alcohol can make you feel much more drowsy than the medication intends.

Can I take these tablets if I’m taking other medication?

If you’re taking any other medications, including herbal remedies or medicines you got without a prescription, you should speak to your doctor or pharmacist before taking Sominex. This especially applies if you are already taking:

  • Other medicines that make you drowsy, e.g. sedatives, relaxants
  • MAOIs (monoamine oxidase inhibitors) which are used for depression. Do not take this product if you have taken MAOIs within the last 14 days
  • Medicines used to reduce or prevent seizures, e.g. epilepsy medicine
  • Strong pain killers, e.g. codeine, morphine, buprenorphine
  • Medicines which treat mental illness, e.g. promazine, flupentixol, haloperidol
  • A pregnancy test which is based on a urine sample, this treatment can cause false negative or positive results
  • An allergy skin test within the next 3 days, this treatment can cause false negative results

What is the right dosage of Sominex?

Take one tablet at bedtime, swallow the tablet with a sip of water. Do not take for more than 7 days in a row. If your symptoms have not improved after taking this product for 7 days you should speak to your doctor. Do not take more than one tablet a day.

When should this product not be used?

Sominex tablets are not suitable for children under the age of 16. Do not take these tablets if you are allergic to promethazine, phenozine drugs (e.g. chlorpromazine, pericyazine), or any of the other listed ingredients. Do not take this product if you have:

  • A concussion
  • Lightheaddedness
  • Drowsiness
  • Dizziness
  • A recent head injury

Speak to your doctor or pharmacist before taking this product if you have:

  • Asthma
  • Breathing problems or bronchitis
  • Seizures, e.g. epilepsy
  • Difficulty peeing
  • Glaucoma
  • Prostate trouble
  • Liver or kidney problems
  • Heart problems
  • A blocked intestine
  • An intolerance to some sugars, as this product contains lactose

Do Sominex sleeping tablets have any side effects?

Like all medications, Sominex sleeping tablets can have side effects, although not everyone will experience them. If you experience any of the following serious side effects you should stop use and seek immediate medical assistance:

  • Allergic reactions, e.g. difficulty breathing or swallowing, being sick, stomach pain, swelling of the face, mouth, tongue, or throat
  • Jaundice, causing yellowing of the skin or eyes
  • Palpitations (feeling your heartbeat), abnormal heart rhythm
  • Low blood pressure, causing dizziness and lightheadedness
  • Blurred or reduced vision or pain in the eye
  • Listlessness, lack of energy
  • Reduction of white blood cells and platelets in the blood, causing ulcers in the mouth or throat, high temperature, bruising easily
  • Convulsions

Other potential side effects you may experience include:

  • Drowsiness
  • Confusion
  • Dizziness, headaches
  • Clumsiness, disorientation
  • Shaking, trembling
  • Stomach upsets, dry mouth
  • Difficulty peeing
  • Restlessness, excitation
  • Feeling sick, being sick
  • Sensitivity to sunlight
  • Difficulty sleeping (insomnia)
  • Ringing in the ears (tinnitus)
  • A blocked or stuffy nose
  • Rashes

If you experience these or any other side effects while using this product, speak to your doctor or pharmacist right away. For more information about reporting the side effects of medications, please see the MHRA’s Yellow Card Scheme.

How to store this product

Store in a cool, dry place. Do not use this product if the expiry date printed on the original packaging has passed. Keep out of sight and reach of children.


Do I need a prescription to buy Sominex?

You do not need a prescription for Sominex Tablets, however, you will be asked to complete a short online survey from our pharmacists before we can take your order. This includes some simple questions that all pharmacies legally are required to ask before supplying this kind of product. This helps our pharmacy team to be sure that this product is the best choice for you.


Important information

This product is a medicine; make sure to speak to your doctor or pharmacist before taking this product if you have an underlying medical problem or are taking any other medicine or complementary therapy. If your symptoms get worse or continue after taking this product, contact your doctor.

If you are pregnant, trying to become pregnant, or breastfeeding, speak to your doctor or pharmacist before taking this product. If you suffer from any allergies, ask your doctor or pharmacist if this medicine is right for you.

Store all medicines out of sight and reach of children.

Please read the included leaflet carefully before using this product.

Helpful Advice on Medication Restrictions & Addiction

For further information on our medication restrictions policy, please click here.

If you are concerned about addiction to 'over the counter' medication, we urge you to visit the below links for professional help and advice:

Sominex Sleep Aid 20mg (Promethazine) - 16 Tablets Reviews

By Jan Farrar,
November 01, 2022
This product helps me sleep when in severe arthritic pain am so glad it was suggested to me
By Suzy Greenwood,
November 01, 2022
Helped with sleep
By Angela Morrison,
August 25, 2022
Best sleep aid. No hanger over feeling in the morning like Nyetol.
By Paul Morgan,
July 26, 2022
Didn’t really work for sleep.
By Anna ,
July 19, 2022
Amazing product. I actually slept

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