Sominex One A Night 20mg – 16 Tablets

Description

Sominex One A Night 20mg – 16 Tablets

Sominex One A Night contains promethazine hydrochloride, an antihistamine used as a short-term aid for occasional sleeplessness in adults. It helps you fall asleep more easily and is intended for temporary use only.

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How It Works

Promethazine hydrochloride belongs to a group of medicines called antihistamines. It works by blocking histamine receptors in the brain, which produces a sedative (drowsy) effect that helps you get to sleep. This effect usually begins within 20–30 minutes of taking the tablet.

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Directions for Use

Sominex One A Night is for adults aged 16 years and over. Take one tablet (20mg) at bedtime, approximately 20–30 minutes before you intend to go to sleep. Do not take more than one tablet in 24 hours, and do not use for more than 7 consecutive nights without speaking to a doctor. This medicine is not suitable for children under 16 years of age. Always read the patient information leaflet before use. If you are unsure about the correct dose, speak to your PillSorted pharmacist.

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Active Ingredients

• Promethazine hydrochloride 20mg per tablet

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Possible Side Effects

• Drowsiness or grogginess the following morning
• Dry mouth
• Blurred vision
• Difficulty urinating
• Dizziness or light-headedness
• Headache
• Restlessness or excitability (more common in children and the elderly)
• Skin sensitivity to sunlight (photosensitivity)

If you experience any serious side effects, stop taking this medicine and seek medical advice immediately.

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Who Should Not Take This Medicine

• Children under 16 years of age
• People who are allergic to promethazine hydrochloride or any other antihistamines
• People with certain breathing problems such as asthma, bronchitis, or chronic obstructive pulmonary disease (COPD)
• People with epilepsy or a history of seizures
• People with glaucoma (raised pressure in the eye)
• People with difficulty passing urine (e.g., due to an enlarged prostate)
• People with severe liver or kidney problems
• Those who have taken monoamine oxidase inhibitors (MAOIs) within the last 14 days

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Interactions

Sominex One A Night can interact with a number of medicines and substances. It may increase the sedative effects of other medicines that cause drowsiness, including sleeping tablets, anxiety medicines, antidepressants, antipsychotics, and certain painkillers. It may also interact with MAOIs, anticholinergic medicines (e.g., some medicines for bladder problems or travel sickness), and some medicines used to treat irregular heartbeats. Tell your PillSorted pharmacist or doctor about all medicines you are currently taking, including herbal remedies and supplements.

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Pregnancy and Breastfeeding

Sominex One A Night is not recommended during pregnancy, as promethazine may have effects on the unborn baby, particularly near the time of delivery. Promethazine passes into breast milk and is not recommended for use while breastfeeding. Speak to your doctor or PillSorted pharmacist before use if you are pregnant, trying to conceive, or breastfeeding.

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Alcohol

You should not drink alcohol while taking Sominex One A Night. Alcohol significantly increases the sedative effect of promethazine, which can cause excessive drowsiness and impair your ability to function safely. Avoid alcohol on the evening you take this medicine and be cautious the following morning if you feel any lingering effects.

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Driving and Operating Machinery

Sominex One A Night causes drowsiness, and this effect may persist into the following day. Do not drive, operate heavy machinery, or perform any tasks that require alertness until you are certain the medicine is no longer affecting you. The morning after taking this medicine, check how you feel before driving or carrying out skilled activities.

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Storage

Store below 25°C in a dry place, away from direct sunlight and moisture. Keep out of sight and reach of children. Do not use after the expiry date shown on the packaging.

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Important Information

• This product is a medicine. Speak to your doctor or PillSorted pharmacist before taking this product if you have an underlying medical condition or are taking any other medication or complementary therapy.
• If symptoms worsen or persist, contact your doctor.
• If pregnant, trying to conceive or breastfeeding, seek medical advice before use.
• If you suffer from allergies, confirm suitability with your PillSorted pharmacist before use.
• Store out of sight and reach of children.
• Read the enclosed patient information leaflet carefully before use.
• Contact your GP where appropriate.

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Patient Information Leaflet

For the full Patient Information Leaflet (PIL) for this medicine, visit the electronic Medicines Compendium (EMC). For further information about this medicine, visit NHS.uk.

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This content has been medically reviewed and approved by Zeinab Ardeshir (GPhC 2075730), Superintendent Pharmacist at PillSorted (GPhC-registered online pharmacy 9011258). Last reviewed: March 2026.

Brand	Sominex
Class	Pharmacy Medicine