Avomine: what the travel sickness label says

Educational summary · drug class: First-generation (sedating) antihistamine, phenothiazine derivative; long-acting antiemetic, 25 mg tablet · last reviewed 2026-06-29

What it is

Avomine is promethazine, but not the same salt as Phenergan: Avomine contains promethazine teoclate, the long-acting form used as an antiemetic, while Phenergan is promethazine hydrochloride. The UK marketing authorisation is held by Manx Pharma, and the SmPC lists several pharmacy own-label travel sickness tablets as the same 25 mg formulation, so the supermarket-pharmacy version you are holding may be Avomine under another name. The tablet is scored and can be divided into equal halves. Its license goes beyond motion sickness to vertigo from Meniere's syndrome, labyrinthitis and other causes. In the US, promethazine is prescription-only.

Availability: UK: available from pharmacies and on prescription (Avomine 25 mg, Manx Pharma). Also a familiar name in several other markets; status varies by country. Legal status, brand names, and availability vary by country: check what applies where you live.

How it may help with motion sickness

The label describes promethazine teoclate as a long-acting antihistamine with antiemetic, central sedative and anticholinergic properties: it crosses into the brain and damps both the histamine and acetylcholine signalling that the inner ear's conflict response runs through. Peak blood levels come 2 to 3 hours after a dose, which explains the label's advance timings, and the long duration is why one evening dose can cover the next day's journey. That same central action is where the drowsiness comes from; the two are not separable.

General timing

For long journeys the label directs one dose each evening at bedtime, starting the day before setting out. For short journeys, one dose 1 to 2 hours before travelling, or as soon after as possible. For sickness already underway it sets out a short schedule starting as soon as possible and repeating that evening and the next. The label also says not to use it for longer than seven days without medical advice. This is general label timing only. We do not provide dosing instructions: follow the pack or your pharmacist's directions.

We don't provide dosing instructions. The exact amount, schedule, and whether it suits you are individual decisions: read the product label and follow its directions, and ask a doctor or pharmacist.

Common side effects

Sources such as the product label commonly list:

• Drowsiness and tiredness (it is a strongly sedating antihistamine)
• Dizziness, restlessness or disorientation
• Headaches or nightmares
• Blurred vision, dry mouth or difficulty passing urine (occasional anticholinergic effects)
• Photosensitive skin reactions: the label says strong sunlight should be avoided during treatment
• Confusion in older adults, who are particularly susceptible
• Paradoxical excitability in some children

Who should check with a doctor or pharmacist first

• Never give it to a child under 2: promethazine can cause fatal respiratory depression in this age group. Tablets are also unsuitable for ages 2 to 5 per the label (a liquid preparation is recommended there); ages 5 to 10 use half amounts and over-10s the lower adult amounts. Speak to a pharmacist before giving it to any child.
• Do not use within 14 days of taking a monoamine oxidase inhibitor (MAOI), or with a phenothiazine allergy, or in coma or CNS depression.
• Driving: the label says first-time users should not drive or control machinery for the first few days until sure it does not cause disorientation, confusion or dizziness.
• Alcohol should be avoided during treatment, and other sedatives, hypnotics, tricyclic antidepressants and anticholinergics add to its effects.
• Pregnancy: the label says it should not be used unless a physician considers it essential, and it is not recommended in the two weeks before delivery. Check with your doctor or pharmacist. Breastfeeding: the amount in milk appears insignificant but neonatal irritability is a noted risk; seek advice.
• Use with caution in asthma, bronchitis or bronchiectasis (it can thicken lung secretions), and in severe coronary artery disease, narrow angle glaucoma, epilepsy, and liver or kidney impairment.
• Avoid strong sunlight during treatment, and do not use for more than 7 days without medical advice. The tablets contain lactose.

Related situation guides

• Promethazine in full
  The ingredient behind Avomine and Phenergan, including the never-under-2 warning.
• Travel sickness guide (UK)
  The UK shelf in one page: the three tablet families, their timings, and which sedates most.
• Medicine names by country
  One table mapping the brand names across the US, Canada, UK, EU and Australia.

Frequently asked questions

This page is for general educational and informational purposes only. It is not medical advice and is not a substitute for the advice of a qualified healthcare professional. Dizzout is not a medical provider: we are not doctors or pharmacists. The information here is a general summary drawn from sources such as the FDA-approved label and other public health resources, and it may not reflect the most current changes; the official product label is the authoritative source. Whether any medicine is right for you, and how much to take, are individual decisions that depend on your health, age, and other medicines. We do not provide dosing instructions: always read the product label and follow its directions. Talk to your doctor or pharmacist before starting, stopping, or changing any medication, and never disregard or delay professional medical advice because of something you read here. If you think you may have a medical emergency, contact a doctor or your local emergency number immediately.