Chlorpheniramine
Pronunciation: klor fen ir' a meen.
- Generic name
- chlorpheniramine maleate (known as chlorphenamine maleate in the United Kingdom)
- Drug class
- First-generation (sedating) antihistamine
- Form
- Tablet, chewable tablet, extended-release (long-acting) tablet or capsule, or liquid to take by mouth, per MedlinePlus. Check your specific product's label for exact form and directions.
- Route
- Oral
- Legal status
- Available over-the-counter in the United States and United Kingdom for oral allergy use, marketed in the US under an OTC drug monograph rather than as an individually FDA-approved product; a separate injectable product also exists in the United Kingdom and is not covered by this page.
Availability and supply rules vary by country
Trade names by country: United States · United Kingdom · Canada
Australia: · Full directory
What chlorpheniramine maleate (known as chlorphenamine maleate in the United Kingdom) is and how it works
Chlorpheniramine is a first-generation antihistamine that blocks the action of histamine, a substance the body releases during an allergic reaction. (1) (3)
It is used over-the-counter for allergy symptoms such as sneezing, runny nose, and itchy, watery eyes. It commonly causes drowsiness, and has a number of conditions that require checking with a doctor or pharmacist first.
Mechanism of action: how chlorpheniramine maleate (known as chlorphenamine maleate in the United Kingdom) works
Chlorpheniramine is a first-generation antihistamine that works by blocking the action of histamine. Further mechanism-of-action detail is not established in the sources reviewed for this dossier. (1) (3)
What chlorpheniramine maleate (known as chlorphenamine maleate in the United Kingdom) is used for
Allergy symptoms (hay fever and other upper respiratory allergies)
Temporarily relieves sneezing, runny nose, itchy or watery eyes, and itching of the nose or throat from hay fever or other upper respiratory allergies. (1) (2)
Hives, insect bites, and mild allergic skin reactions (United Kingdom)
UK licensed use also includes hives (urticaria), insect bites, food-allergy reactions, and itching related to mild eczema-type allergic skin reactions. (3)
Before taking chlorpheniramine maleate (known as chlorphenamine maleate in the United Kingdom)
Do not take / not appropriate for
- Do not take chlorphenamine if you have had an allergic reaction to chlorpheniramine or chlorphenamine. (United Kingdom (chlorphenamine); this is not established in the reviewed US OTC label) (3)
- Do not take chlorphenamine if you have primary angle-closure glaucoma, or if you have taken a monoamine oxidase inhibitor (MAOI) antidepressant within the last 14 days. (United Kingdom (chlorphenamine); the reviewed US OTC label instead advises asking a doctor before use for glaucoma and does not mention MAOIs) (3)
Tell your clinician about
- Glaucoma of any type, breathing problems such as asthma, emphysema, or chronic bronchitis, or difficulty urinating from an enlarged prostate.
- Epilepsy or another condition that causes seizures.
- Heart disease or severe high blood pressure.
- Liver or kidney disease.
- Diabetes.
- Whether you are 65 or older, since older adults are generally advised to avoid this medicine and frail older adults need a reduced, less frequent dose if it is used.
- Whether you are taking a sedative or tranquilliser, since combining them with chlorpheniramine can increase drowsiness.
- Pregnancy or breastfeeding.
- Whether you are due to have an allergy test, since chlorpheniramine may affect the results and you might need to stop taking it a few days beforehand; ask your pharmacist or doctor for advice.
How to take chlorpheniramine maleate (known as chlorphenamine maleate in the United Kingdom)
- Take exactly as directed on the product label or by your prescriber.
- Follow the dosing directions on your specific product's label or from your prescriber; the amount and frequency differ by country and product.
- Can be taken with or without food.
- Do not give this medicine to make a child sleepy.
- It's best to avoid alcohol, since it can make you feel very sleepy; ask your doctor about safe alcohol use while taking this medicine. Be cautious with driving or operating machinery until you know how this medicine affects you, because it can cause drowsiness.
Procedures and treatment changes
Tell the treating team before surgery, procedures, or any medicine change. Do not alter treatment without the responsible clinician. (1) (2) (3)
Missed dose
If you are taking this medicine only as needed, there is no missed-dose schedule to follow. If you are taking it on a regular schedule, take the missed dose as soon as you remember, unless it is almost time for the next dose; skip the missed dose and continue your regular schedule. do not take an extra dose to make up for a missed one. If you are unsure, ask your pharmacist or prescriber.
Overdose
In the United States, contact a poison control centre immediately if an overdose is suspected, even without symptoms: call 1-800-222-1222. In the United Kingdom, call 999 or go to A&E for symptoms such as a fast heartbeat, breathing difficulty, seizures, loss of consciousness, uncontrolled movements, confusion, or hallucinations; call 111 for advice if there are no symptoms. (1) (3)
Side effects
Drowsiness is the most common effect.
Drowsiness
What to notice: Sleepiness that usually wears off within about 4 to 6 hours of a dose.
What to do: Avoid driving or operating machinery until you know how it affects you. (1) (3)
Dry mouth, nausea, dizziness, headache, or blurred vision
What to notice: These are commonly reported.
What to do: Sugar-free gum or sweets can help dry mouth; taking the dose with food may help nausea; sit or lie down for dizziness; tell the pharmacist or prescriber if any of these are severe or persistent. (1) (3)
Possible liver problem, bleeding problem, or urinary difficulty
What to notice: Yellowing of the skin or eyes, unusual bruising or bleeding, or difficulty urinating.
What to do: Seek medical advice promptly; a clinician will decide whether chlorpheniramine needs to be stopped. (3)
Serious warnings
Serious allergic reaction (anaphylaxis) — emergency
Symptoms: Swelling of the lips, mouth, throat, or tongue, severe breathing difficulty or wheezing, throat tightness or difficulty swallowing, skin/lips/tongue turning blue, grey, or pale, sudden confusion or severe drowsiness, or loss of consciousness.
Action: Call emergency services (999 in the UK, or your local emergency number) immediately. (3)
Interactions
| Medicine or test | Effect | Action |
|---|---|---|
| Monoamine oxidase inhibitors (MAOIs) | Antihistamine effects can be intensified by MAOIs; this is a United Kingdom-sourced restriction, not established in the reviewed US OTC label. | In the United Kingdom, do not take chlorphenamine within 14 days of taking an MAOI antidepressant. (3) |
| Sedatives, tranquillisers, and alcohol | Combined use can increase drowsiness and impairment. | Ask a doctor or pharmacist before combining with sedatives or tranquillisers. It's best to avoid alcohol; ask your doctor about safe alcohol use while taking this medicine. (2) (3) |
Pregnancy, breastfeeding, kidney/liver function, age
Older adults
Adults aged 65 and older are generally advised to avoid this medicine. If a frail older adult is prescribed it, a reduced, less frequent dose is used and confusion is more likely; this should be a clinician's decision. (1) (3)
Pregnancy and breastfeeding
Tell your doctor or pharmacist before use if you are pregnant or breastfeeding. (2)
Children
United Kingdom: chlorphenamine can usually be given from age 1, but babies under 1 should only take it if a doctor has prescribed it, and children under 6 should not be given combined cough/cold products containing it. United States: the reviewed OTC Drug Facts label states children under 6 should not use this product. Never give it to make a child sleepy. (2) (3)
Monitoring
Before starting
- Confirm age, and screen for glaucoma, urinary retention/prostate enlargement, seizure disorders, asthma or lung disease, heart disease or severe hypertension, and liver or kidney disease. In the United Kingdom, also screen for recent MAOI use, which is a contraindication there but not established in the reviewed US label.
- Ask about other sedating medicines and alcohol use.
During treatment
- Watch for excessive drowsiness or confusion, especially in frail older adults.
- Seek prompt advice for jaundice, unusual bruising/bleeding, or urinary difficulty; a clinician will decide whether chlorpheniramine needs to be stopped. Seek emergency care for signs of a serious allergic reaction.
Storage
Store at controlled room temperature in a tightly closed container, away from excess heat and moisture, and out of reach of children.
Study the drug class: Antihistamines
Professional information
Clinician-facing context only. Use the current local product information for exact dosing.
United States (OTC Drug Facts label)
Indication: Allergy symptoms
Dose summary: Adults and children 12+: 1 tablet (4 mg), not exceeding 6 tablets in 24 hours (per the reviewed Drug Facts label); MedlinePlus describes regular-form dosing as usually every 4-6 hours. Children 6 to under 12: 1/2 tablet, not exceeding 3 whole tablets in 24 hours. Children under 6: do not use, per the reviewed Drug Facts label.
Renal context: Renal/hepatic-impairment-specific adjustment is not established in the sources reviewed for this dossier. (2) (1)
United Kingdom
Indication: Allergy symptoms
Dose summary: Adults and children 12+: 1 tablet (4 mg) every 4-6 hours, maximum 6 tablets in 24 hours. Frail older adults: 1 tablet every 6-8 hours, maximum 3 tablets in 24 hours. Lower, age-specific doses apply to younger children per the product leaflet.
Renal context: Use caution and current local product information in liver or kidney impairment. (3)
Hepatic guidance
Use local product information and clinical judgement; this page does not provide impairment-specific dosing.
Overdose note
Overdose can cause CNS effects including seizures, hallucinations, and confusion, as well as cardiovascular effects such as tachycardia; manage per local poison-control and emergency guidance. (1) (3)
Frequently asked questions
Why does chlorpheniramine make me sleepy?
It is a first-generation antihistamine, and drowsiness is its most common side effect, usually wearing off 4 to 6 hours after a dose. Avoid driving or hazardous tasks until you know how it affects you. (1) (3)
Can older adults take chlorpheniramine?
It is generally best avoided in adults 65 and older. If a frail older adult needs it, a lower, less frequent dose is used under medical guidance because confusion is more likely. (1) (3)
Is the injectable form of chlorphenamine the same as the tablets?
No. This page covers the oral dosage forms (tablet, chewable tablet, extended-release tablet or capsule, and liquid) only. A separate injectable product exists in the United Kingdom and is not covered here. (3)
What is the mechanism of action of chlorpheniramine maleate (known as chlorphenamine maleate in the United Kingdom)?
Chlorpheniramine is a first-generation antihistamine that works by blocking the action of histamine. Further mechanism-of-action detail is not established in the sources reviewed for this dossier. (1) (3)
References
- Chlorpheniramine: MedlinePlus Drug InformationMedlinePlus, U.S. National Library of Medicine · United States · accessed 2026-07-26 · source 1
- ALLERGY - chlorpheniramine maleate 4 mg tablet - Drug Facts labelDailyMed, U.S. National Library of Medicine (OTC Drug Facts label) · United States · accessed 2026-07-26 · source 2
- Chlorphenamine (including Piriton)NHS (United Kingdom) · United Kingdom · accessed 2026-07-26 · source 3
Brand names by country
Single-ingredient chlorpheniramine maleate (known as chlorphenamine maleate in the United Kingdom) names are shown separately by country. Product availability, strengths, and supply rules can change; combination products are not included here.
Priority countries
United States
- ClorRelief5 mg/mL · ferrer medical innovations llc
- ED CHLORPED JR2 mg/5mL · edwards pharmaceuticals, inc.
- Allergy Time4 mg · time cap labs inc
- Aller-chlor4 mg · rugby laboratories
- Pharbechlor4 mg · ulai health llc
- Medique Chlorphen4 mg · unifirst first aid corporation
- Chlorphen-1212 mg · kvk-tech, inc.
- SPRINSOL4 mg · fortune pharmacal company limited
United Kingdom
- Piriton (3)verified
Canada
- CHLOR-TRIPOLON 12 HOUR
- CHLOR-TRIPOLON
- NOVO-PHENIRAM