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Periactin 4mg (30 Tablets)

Periactin 4mg (30 Tablets)

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  • ✔️ Relieves hay fever, urticaria, and allergic itching effectively
  • ✔️ Blocks histamine receptors to reduce allergic skin reactions
  • ✔️ First-generation antihistamine with established clinical track record
  • ✔️ Suitable for adults and children aged 2 years and over
  • ✔️ 30-tablet pack provides a practical short-term allergy treatment course

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What Are Cyproheptadine Tablets Used For?

 

Periactin 4mg tablets contain cyproheptadine hydrochloride, a first-generation antihistamine used to relieve a range of allergic conditions. If you suffer from hay fever, skin rashes, or persistent itching, this medicine works by blocking the histamine response that triggers those uncomfortable symptoms. It has been used clinically for decades and remains a trusted option for people who need reliable allergy relief. You can browse our full range of allergy and hay fever treatments if you want to compare your options before buying.

Each tablet contains 4mg of cyproheptadine hydrochloride. The pack contains 30 tablets, making it a practical choice for managing seasonal or ongoing allergic symptoms. This is a medicine — speak to your pharmacist or GP before use if you have any underlying health conditions or take other medicines regularly.

 

How Do Periactin Tablets Work in the Body?

 

Cyproheptadine works by competitively blocking peripheral H1 histamine receptors. When your immune system encounters an allergen — pollen, dust mites, animal dander — it releases histamine. That histamine binds to receptors throughout the body, causing the sneezing, itching, watery eyes, and skin reactions you know all too well. Cyproheptadine steps in and occupies those receptors before histamine can, reducing the severity of the reaction.

  • Blocks H1 histamine receptors in peripheral tissues
  • Reduces histamine-driven inflammation and itching
  • Has additional antiserotonergic activity, which may contribute to its appetite-stimulating effect
  • Crosses the blood-brain barrier, which accounts for its sedating properties

Because it is a first-generation antihistamine, it does cross into the central nervous system more readily than newer alternatives. That is why drowsiness is a well-recognised side effect — something worth bearing in mind if you need to drive or concentrate at work.

 

Who Is Periactin 4mg Suitable For?

 

Periactin is suitable for adults and children aged 2 years and over who experience allergic symptoms. It is particularly useful for people who find non-sedating antihistamines insufficient, or for those whose allergy symptoms are severe enough to warrant a stronger histamine-blocking effect. That said, it is not appropriate for everyone.

  • Adults with hay fever, allergic rhinitis, or urticaria
  • Children aged 2 and over (dose must be adjusted by age/weight — consult a pharmacist)
  • People with chronic pruritus (itching) linked to allergic skin conditions
  • Patients who have not responded adequately to non-sedating antihistamines

It is not suitable for people with glaucoma, urinary retention, severe liver disease, or those taking monoamine oxidase inhibitors (MAOIs). Elderly patients should use it with caution due to increased sensitivity to anticholinergic effects.

 

How Does Periactin Compare to Other Antihistamines?

 

Feature Periactin 4mg (Cyproheptadine) Cetirizine 10mg
Generation First-generation Second-generation
Sedation Yes — commonly causes drowsiness Low — minimal sedation
Dosing frequency Three times daily Once daily
Additional properties Antiserotonergic, anticholinergic Antihistamine only

 

How Should You Store Periactin Tablets?

 

Cyproheptadine tablets should be stored below 25°C in a dry place, away from direct sunlight and out of the reach of children. Do not use the tablets after the expiry date printed on the packaging. If you are unsure whether your tablets are still suitable to use, ask your pharmacist — never take a medicine that looks or smells unusual.

Keep the tablets in their original blister packaging until you are ready to take them. Moisture and heat can degrade the active ingredient over time, so avoid storing them in bathrooms or near kitchen hobs. If you have unused tablets after completing your course, return them to your local pharmacy for safe disposal rather than putting them in household waste.

This product is a medicine. Speak to your doctor or pharmacist before using if you have an underlying medical condition or are taking other medicines.

Periactin 4mg (30 Tablets) specifications
Treatment category Allergy & Hay Fever
Active ingredient Cyproheptadine hydrochloride 4mg
Drug class First-generation antihistamine
Mechanism of action H1 histamine receptor antagonist with antiserotonergic activity
Route of administration Oral
Preparation Tablet
Strengths 4mg
Pack sizes 30 tablets
Suitable for Adults and children aged 2 years and over
UK classification POM (Prescription Only Medicine in standard UK supply — check with pharmacist)

Specifications of Periactin 4mg (30 Tablets)

 

What Is Periactin and What Is It Used For?

 

Periactin 4mg tablets contain cyproheptadine hydrochloride, a first-generation antihistamine. It is used to relieve the symptoms of allergic conditions, including hay fever (allergic rhinitis), urticaria (hives), angioedema, pruritus (itching), and other hypersensitivity reactions. The NHS recognises antihistamines as a first-line treatment for many of these conditions, and cyproheptadine has a long-established clinical history in the UK.

Unlike newer, non-sedating antihistamines, cyproheptadine also has antiserotonergic properties. This means it is sometimes used off-label by clinicians for appetite stimulation in certain patient groups, though this use should only be undertaken under medical supervision. For most people, the primary reason for taking Periactin is straightforward allergy symptom relief.

 

What Do You Need to Know Before Using Periactin?

 

Before taking Periactin, it is important to check whether it is appropriate for you. There are several conditions and medicines that may make this treatment unsuitable or require extra caution.

Do not take Periactin if you:

  • Are allergic to cyproheptadine or any other ingredient in the tablet
  • Have narrow-angle glaucoma
  • Have urinary retention or an enlarged prostate
  • Have severe liver disease
  • Are currently taking monoamine oxidase inhibitors (MAOIs) or have taken them within the last 14 days
  • Are a newborn or premature infant
  • Are breastfeeding (antihistamines may pass into breast milk)

Tell your pharmacist or doctor if you:

  • Have epilepsy or a history of seizures
  • Have cardiovascular disease or high blood pressure
  • Have hyperthyroidism
  • Are pregnant or planning to become pregnant
  • Are elderly — anticholinergic effects are more pronounced in older adults

Known drug interactions — tell your pharmacist if you take:

  • Other sedating medicines, including sleeping tablets or opioid painkillers
  • Alcohol — this significantly increases sedation
  • Tricyclic antidepressants or other anticholinergic medicines
  • MAOIs — combination is contraindicated
  • CNS depressants of any kind

 

How Should You Use Periactin Correctly?

 

Always take Periactin exactly as directed by your pharmacist or as stated in the patient information leaflet. Swallow the tablets whole with a glass of water. They can be taken with or without food, though taking them with food may help if you experience any stomach discomfort.

  1. Read the patient information leaflet before starting treatment
  2. Take one tablet (4mg) by mouth, three times daily for adults
  3. Space doses evenly throughout the day
  4. Do not exceed the maximum daily dose of 32mg in adults
  5. For children, always confirm the correct dose with a pharmacist before administering
  6. If you miss a dose, take it as soon as you remember — but skip it if your next dose is due soon
  7. Never double up doses to compensate for a missed one
Age Group Dose Frequency Maximum Daily Dose
Adults 4mg Three times daily 32mg
Children 7–14 years 4mg Two to three times daily 16mg
Children 2–6 years 2mg Two to three times daily 12mg
Under 2 years Not recommended

If you are managing multiple allergy-related symptoms, you may also find it helpful to explore our ear, nose, and throat treatments for complementary relief options.

 

What Are the Possible Side Effects of Periactin?

 

Like all medicines, Periactin can cause side effects, though not everyone experiences them. Being aware of what to look out for helps you manage your treatment safely.

Common side effects:

  • Drowsiness or sedation — particularly at the start of treatment
  • Dry mouth
  • Dizziness
  • Blurred vision
  • Increased appetite and weight gain
  • Nausea or stomach upset

Less common side effects:

  • Urinary retention or difficulty passing urine
  • Constipation
  • Headache
  • Confusion or disorientation (more common in elderly patients)
  • Skin rash or hypersensitivity reactions
  • Palpitations

If you experience a severe allergic reaction — including swelling of the face, lips, or throat, difficulty breathing, or a widespread rash — stop taking the medicine and seek emergency medical attention immediately. These reactions are rare but serious.

 

How Should You Store Periactin Tablets?

 

  • Store below 25°C in a cool, dry place
  • Keep away from direct sunlight and sources of heat
  • Store in the original blister packaging until use
  • Keep out of the reach and sight of children
  • Do not use after the expiry date printed on the pack
  • Return unused or expired tablets to your local pharmacy — do not dispose of in household waste or flush down the toilet

If you have any questions about storing or disposing of this medicine, your pharmacist will be happy to help. You can also find further guidance on managing allergy symptoms through our allergy and hay fever collection.

Written and reviewed by our qualified team

Your safety and success are our highest priorities. Our medical team rigorously evaluates every product and piece of advice we provide, ensuring you receive only the most effective, science-backed solutions available.

Frequently Asked Questions

Where can I buy Periactin 4mg online in the UK?

You can buy Periactin 4mg (30 Tablets) directly from Cured Pharmacy, a GPhC-registered online pharmacy operating in the UK. Simply add the product to your basket and complete a short health check at checkout. Our pharmacist team reviews every order to ensure the medicine is appropriate for you before dispatch.

How does cyproheptadine work in the body?

Cyproheptadine is a first-generation antihistamine that blocks H1 histamine receptors, preventing histamine from triggering allergic symptoms such as itching, sneezing, and skin reactions. It also has antiserotonergic properties, which is why it can affect appetite in some patients. Because it crosses the blood-brain barrier, it tends to cause more sedation than newer antihistamines.

What is the correct dose of Periactin 4mg for adults?

The standard adult dose of Periactin is one 4mg tablet taken three times daily. The maximum recommended daily dose for adults is 32mg — do not exceed this. If you are unsure about your dose, speak to your pharmacist before starting treatment.

What is the best time to take Periactin tablets?

Because Periactin causes drowsiness, many people find it helpful to take one dose in the evening and space the remaining doses through the day when sedation is less disruptive. Taking tablets with food can help reduce any stomach discomfort. Always try to space your doses evenly — roughly every 6 to 8 hours.

Can Periactin cause drowsiness and how do I manage it?

Yes, drowsiness is one of the most commonly reported side effects of Periactin because cyproheptadine is a sedating antihistamine. To manage this, avoid driving or operating machinery until you know how the medicine affects you, and consider taking your doses in the evening where possible. If drowsiness is significantly affecting your daily life, speak to your pharmacist about whether a non-sedating alternative might be more suitable.

Is Periactin safe for children to take?

Periactin can be used in children aged 2 years and over, but the dose must be carefully adjusted based on the child's age and weight. Children aged 2–6 years typically take 2mg two to three times daily, while those aged 7–14 years may take 4mg two to three times daily. Always consult a pharmacist or GP before giving this medicine to a child, and never give it to infants under 2 years.

Who is eligible to use Periactin 4mg tablets?

Periactin is suitable for adults and children aged 2 and over who experience allergic conditions such as hay fever, urticaria, or pruritus. It is not suitable for people with glaucoma, urinary retention, severe liver disease, or those taking MAOIs. Pregnant or breastfeeding women should seek medical advice before use.

What happens if I miss a dose of Periactin?

If you miss a dose, take it as soon as you remember — unless your next scheduled dose is due within a couple of hours, in which case simply skip the missed dose and continue as normal. Never take a double dose to make up for a missed one, as this increases the risk of side effects. If you regularly forget doses, setting a phone reminder can help.

What are the alternatives to Periactin for allergy relief?

Non-sedating antihistamines such as cetirizine, loratadine, and fexofenadine are widely used alternatives that cause significantly less drowsiness. These are often preferred for daytime use or for people who drive regularly. You can explore a range of options in our allergy and hay fever collection to find the most suitable treatment for your symptoms.

How long can you take Periactin for?

Periactin is generally intended for short-term use to manage acute allergic symptoms. If you find you need to take it continuously for more than a few weeks, it is worth speaking to your GP or pharmacist to review your treatment plan. Long-term use of sedating antihistamines is not routinely recommended without medical oversight.

Can I drink alcohol while taking Periactin?

No — you should avoid alcohol while taking Periactin. Alcohol significantly increases the sedating effects of cyproheptadine, which can impair your ability to drive, concentrate, or react quickly. Even small amounts of alcohol can make drowsiness considerably worse when combined with this medicine.

Does Periactin interact with other medicines?

Yes, Periactin has several important drug interactions. It should not be taken with MAOIs, and caution is needed with other CNS depressants, tricyclic antidepressants, opioid painkillers, and other anticholinergic medicines. Always tell your pharmacist about every medicine, supplement, or herbal remedy you are taking before starting Periactin.

Can Periactin be used for conditions other than allergies?

Cyproheptadine is sometimes used off-label by clinicians for appetite stimulation in certain patient groups, due to its antiserotonergic properties. However, this use should only be undertaken under direct medical supervision and is not an approved indication for self-treatment. If you are considering Periactin for anything other than allergy relief, speak to your GP first.

What are the latest findings on cyproheptadine use?

Cyproheptadine remains a well-established antihistamine with a long clinical track record. Current NHS and BNF guidance continues to support its use for allergic conditions, though non-sedating antihistamines are generally preferred as first-line treatment for most patients due to their more favourable side-effect profile. Research into its off-label uses, including appetite stimulation, is ongoing but remains outside standard prescribing guidelines for self-care.

Can I take Periactin alongside cold and flu remedies?

You should be cautious about combining Periactin with cold and flu remedies, as many of these products already contain antihistamines or decongestants that can interact with cyproheptadine. Taking multiple antihistamines together increases the risk of side effects, including excessive sedation. Check with your pharmacist before combining any medicines — you can also browse our cold and flu range for suitable options.

How Should You Use Periactin 4mg Tablets?

Periactin tablets are taken by mouth and should be swallowed whole with a full glass of water. You can take them with or without food, though taking them alongside a meal may help if you notice any stomach discomfort after swallowing.

What Is the Correct Dose of Periactin 4mg?

Dosing varies depending on your age. Adults typically take one 4mg tablet three times daily, while children require lower doses based on their age group. Always confirm the correct dose with a pharmacist before giving this medicine to a child, and never exceed the stated maximum daily dose for any age group.

When Is the Best Time to Use Periactin Tablets?

Because cyproheptadine commonly causes drowsiness, many people find it practical to take one of their daily doses in the evening, when sedation is less likely to interfere with work or daily activities. If you are taking it three times a day, spacing doses at morning, afternoon, and bedtime is a sensible approach. Avoid taking a dose immediately before driving or operating machinery.

If you are using Periactin for seasonal hay fever, starting treatment a few days before your expected exposure to pollen may help you manage symptoms more effectively from the outset.

How Long Can You Use Periactin For?

Periactin is generally intended for short-term use during periods of acute allergic symptoms. Most people use it for a few days to a few weeks at a time, depending on the nature and duration of their allergy trigger. If your symptoms persist beyond a few weeks or worsen despite treatment, you should speak to your GP or pharmacist to reassess your management plan.

Long-term continuous use of sedating antihistamines is not routinely recommended without medical review, as tolerance to the sedating effects can develop and the underlying cause of your allergy may benefit from further investigation.

Do not exceed the recommended dose. If in doubt, speak to your pharmacist.

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What Are the Most Common Side Effects of Periactin?

The most frequently reported side effect of Periactin is drowsiness or sedation. Because cyproheptadine is a first-generation antihistamine that crosses the blood-brain barrier, it has a more pronounced sedating effect than newer alternatives. This is particularly noticeable when you first start taking it, and may lessen as your body adjusts over the first few days.

  • Drowsiness or excessive sleepiness
  • Dry mouth
  • Dizziness or light-headedness
  • Increased appetite and weight gain
  • Nausea or mild stomach upset
  • Blurred vision

What Are the Less Common Side Effects of Periactin?

Some people experience side effects that are less frequent but still worth being aware of. These tend to be more common in elderly patients or those taking higher doses. If any of the following become troublesome, speak to your pharmacist or GP.

  • Difficulty passing urine (urinary retention)
  • Constipation
  • Headache
  • Confusion or disorientation — particularly in older adults
  • Palpitations or a faster heartbeat
  • Skin rash or mild hypersensitivity reaction
  • Nervousness or excitability — more common in children

What Are the Serious Side Effects of Periactin?

Serious side effects from Periactin are rare, but you should be aware of the signs that require urgent medical attention. A severe allergic reaction (anaphylaxis) to cyproheptadine itself is uncommon but possible. Symptoms include sudden swelling of the face, lips, tongue, or throat, difficulty breathing, a widespread skin rash, or a sudden drop in blood pressure causing collapse.

If you experience any of these symptoms, stop taking the medicine immediately and call 999 or go to your nearest A&E department. Do not wait to see if symptoms improve on their own.

What Should You Do If You Experience Side Effects?

For mild side effects such as dry mouth or drowsiness, these often improve after the first few days of treatment. Staying well hydrated, avoiding alcohol, and timing your doses to minimise disruption to your daily routine can all help. If side effects persist or feel unmanageable, your pharmacist can advise on whether to adjust your dose or switch to an alternative antihistamine.

You can also report suspected side effects directly to the MHRA via the Yellow Card scheme at yellowcard.mhra.gov.uk. This helps regulators monitor the safety of medicines in real-world use.

Can Periactin Interact With Other Medicines?

Yes — Periactin has several clinically significant interactions. Taking it alongside other CNS depressants, including opioid painkillers, sleeping tablets, or alcohol, significantly increases sedation and can be dangerous. Combining it with MAOIs is contraindicated and can cause serious adverse effects. Tricyclic antidepressants and other anticholinergic medicines may also intensify side effects such as dry mouth, urinary retention, and confusion.

Always tell your pharmacist or GP about every medicine, supplement, or herbal remedy you are currently taking before starting Periactin. This includes over-the-counter products, as some cold and flu remedies already contain antihistamines.

If you are concerned about any side effects, contact your pharmacist or GP immediately.

Patient Information Leaflet

Important - Before taking any medication, it is always important to read the Patient Information Leaflet (PIL)

Written and reviewed by our qualified team

GPhC Number: 2233073
Tarun Kumar

Reviewed by:

Tarun Kumar

Superintendent/ Clinical Lead

📖 Find out more about our team of medical content authors and how we ensure the accuracy of our content with our content guidelines.

Content last updated: 31 Mar 2025

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