Chlorphenamine — Drug Interactions, Alcohol & Pregnancy Guide
Last reviewed: · Source: US FDA drug label database · 247CanITakeWith Editorial Team
- Chlorphenamine is a First-generation antihistamine used for Hay fever.
- Alcohol: Avoid alcohol with chlorphenamine (Piriton) — this older antihistamine is sedating on its own, and alcohol dramatically increases drowsiness, impairing driving and coordination.
- Pregnancy: Chlorphenamine (Piriton) is the most-studied antihistamine in pregnancy and is sometimes recommended when modern antihistamines are insufficient — but it causes significant sedation.
About Chlorphenamine
Chlorphenamine (Piriton) is a sedating antihistamine for allergies and itching. Unlike modern antihistamines (cetirizine, loratadine), it causes significant drowsiness. Do not drive after taking it.
Also sold as: Piriton, chlorpheniramine
Chlorphenamine at a glance
Chlorphenamine is classed as first-generation antihistamine and is used for hay fever, urticaria (hives), allergic reactions, itching, hyperemesis gravidarum (part of protocols). It can be bought over the counter in the UK, but that does not mean it is safe with everything — check the label and ask a pharmacist if you take other medicines.
Typical adult dosing guidance: 4mg every 4-6 hours, maximum 24mg in 24 hours. Your own label or prescription always takes priority over general figures.
Interactions most often flagged
- Alcohol
- Benzodiazepines
- Opioids
- Pregnancy (caution)
Before you combine Chlorphenamine with anything new
- Read the patient information leaflet for both products.
- Keep one up-to-date list of every medicine and supplement you take.
- Ask a pharmacist — it is free and takes a couple of minutes.
- Seek urgent medical help if you feel seriously unwell after combining medicines.
Chlorphenamine and Alcohol
Avoid alcohol with chlorphenamine (Piriton) — this older antihistamine is sedating on its own, and alcohol dramatically increases drowsiness, impairing driving and coordination.
Full guide →Chlorphenamine in Pregnancy
Chlorphenamine (Piriton) is the most-studied antihistamine in pregnancy and is sometimes recommended when modern antihistamines are insufficient — but it causes significant sedation.
Full guide →More in this category: allergy
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Frequently Asked Questions
What is Chlorphenamine used for?
Chlorphenamine is a First-generation antihistamine used for Hay fever, Urticaria (hives), Allergic reactions, Itching, Hyperemesis gravidarum (part of protocols).
What is the maximum adult dose of Chlorphenamine?
The maximum adult dose is 4mg every 4-6 hours, maximum 24mg in 24 hours. This is general guidance — always follow the dose on your prescription or product label, and check with a pharmacist if you're unsure.
Can I drink alcohol with Chlorphenamine?
Avoid alcohol with chlorphenamine (Piriton) — this older antihistamine is sedating on its own, and alcohol dramatically increases drowsiness, impairing driving and coordination.
Is Chlorphenamine safe to take during pregnancy?
Chlorphenamine (Piriton) is the most-studied antihistamine in pregnancy and is sometimes recommended when modern antihistamines are insufficient — but it causes significant sedation.
Is Chlorphenamine available over the counter in the UK?
Yes, Chlorphenamine is available over the counter in the UK.
What should I check before taking Chlorphenamine with other medicines?
The interactions most often flagged for Chlorphenamine are: alcohol, benzodiazepines, opioids, pregnancy (caution). Tell your pharmacist or prescriber about everything you take, including over-the-counter products, supplements and herbal remedies, before combining it with anything new.
What are the brand names for Chlorphenamine?
Chlorphenamine is sold under brand names including Piriton, chlorpheniramine. The active ingredient is the same, so check labels carefully to avoid doubling up on it.
Do I need a prescription for Chlorphenamine?
Chlorphenamine does not need a prescription in the UK, but a pharmacist can still advise whether it suits you alongside your other medicines.
Not sure if Chlorphenamine is safe with your other medications?
HealthLabs.com lets you check liver enzyme or kidney function levels before combining medications long-term — no GP referral needed.
Check your levels at HealthLabs →Always speak to your pharmacist or GP for personalised medical advice. Affiliate link — we may earn a commission.