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Piriton Tablets

Active Ingredient:
chlorphenamine maleate
Haleon UK Trading Limited See contact details
About Medicine
{healthcare_pro_orange} This information is for use by healthcare professionals
Last updated on emc: 17 Apr 2023
1. Name of the medicinal product

Piriton Tablets

2. Qualitative and quantitative composition

Each tablet contains 4 milligrams of chlorphenamine maleate

Round, circular, biconvex, yellow tablets engraved with a 'P' to one side of the breakline; the reverse face has a breakline only.

3. Pharmaceutical form

Tablet. The tablet can be divided into equal doses.

4. Clinical particulars
4.1 Therapeutic indications

Piriton tablets are indicated for symptomatic control of all allergic conditions responsive to antihistamines, including hay fever, vasomotor rhinitis, urticaria, angioneurotic oedema, food allergy, drug and serum reactions, insect bites.

Also indicated for the symptomatic relief of itch associated with chickenpox.

4.2 Posology and method of administration

Oral Administration only

Do not exceed the stated dose or frequency of dosing

Minimum dosing interval: 4 hours

Do not use continuously for more than two weeks without consulting a doctor.

Adults and children 12 years and over: 1 tablet 4 to 6 hourly. Maximum daily dose: 6 tablets (24 mg) in any 24 hours

Elderly: The elderly are more likely to experience neurological anticholinergic effects. Consideration should be given to using a lower daily dose (e.g. a maximum of 12 mg in any 24 hours).

Children aged 6 - 12 years: ½ tablet 4 to 6 hourly. Maximum daily dose: 3 tablets (12mg) in any 24 hours

Not recommended for children under 6 years


Patients with renal or hepatic impairment should seek doctor's advice prior to taking this medicine. (See Section 4.4 Special warnings and precautions for use).

4.3 Contraindications

Piriton tablets are contra-indicated in patients who are hypersensitive to antihistamines or to any of the tablet ingredients.

The anticholinergic properties of chlorphenamine are intensified by monoamine oxidase inhibitors (MAOIs). Piriton Tablets is therefore contra-indicated in patients who have been treated with MAOIs within the last fourteen days.

4.4 Special warnings and precautions for use

Chlorphenamine, in common with other drugs having anticholinergic effects, should be used with caution in epilepsy; raised intra-ocular pressure including glaucoma; prostatic hypertrophy; severe hypertension or cardiovascular disease; bronchitis, bronchiectasis and asthma; hepatic impairment; renal impairment. Children and the elderly are more likely to experience the neurological anticholinergic effects and paradoxical excitation (eg. increased energy, restlessness, nervousness). Avoid use in elderly patients with confusion.

The anticholinergic properties of chlorphenamine may cause drowsiness, dizziness, blurred vision and psychomotor impairment in some patients which may seriously affect ability to drive and use machinery.

Concurrent use with drugs which cause sedation such as anxiolytics and hypnotics may cause an increase in sedative effects, therefore medical advice should be sought before taking chlorphenamine concurrently with these medicines.

The effects of alcohol may be increased and therefore concurrent use should be avoided.

Should not be used with other antihistamine containing products, including antihistamine containing cough and cold medicines.

Patients with rare hereditary problems of galactose intolerance, Lapp lactase deficiency or glucose-galactose malabsorption should not take this medicine,

Keep out of sight and reach of children.

4.5 Interaction with other medicinal products and other forms of interaction

Concurrent use of chlorphenamine and hypnotics or anxiolytics may cause an increase in sedative effects, concurrent use of alcohol may have a similar effect therefore medical advice should be sought before taking chlorphenamine concurrently with these medicines.

Chlorphenamine inhibits phenytoin metabolism and can lead to phenytoin toxicity.

The anticholinergic effects of chlorphenamine are intensified by MAOIs (see Contra-indications).

4.6 Fertility, pregnancy and lactation


There are no adequate data from the use of chlorphenamine maleate in pregnant women. The potential risk for humans is unknown. Use during the third trimester may result in reactions in the newborn or premature neonates. Not to be used during pregnancy unless considered essentially by a physician.


Chlorphenamine maleate and other antihistamine may inhibit lactation and may be secreted in breast milk. Not to be used during lactation unless considered essential by a physician

4.7 Effects on ability to drive and use machines

The anticholinergic properties of chlorphenamine may cause drowsiness, dizziness, blurred vision and psychomotor impairment, which can seriously hamper the patients' ability to drive and use machinery.

4.8 Undesirable effects

The following convention has been utilised for the classification of the frequency of adverse reactions: very common (>1/10), common (>1/100 to <1/10), uncommon (>1/1000 to <1/100), rare (>1/10,000 to <1/1000) and very rare (<1/10,000), not known (cannot be estimated from available data).

Adverse reactions identified during post-marketing use with chlorphenamine are listed below. As these reactions are reported voluntarily from a population of uncertain size, the frequency of some reactions is unknown but likely to be rare or very rare:

System Organ Class

Adverse Reaction


Nervous system disorders*

Sedation, somnolence

Very common

Disturbance in attention, abnormal coordination, dizziness headache


Eye disorders

Blurred Vision


Gastrointestinal disorders

Nausea, dry mouth


Vomiting, abdominal pain, diarrhoea, dyspepsia


Immune system disorders:

Allergic reaction, angioedema, anaphylactic reactions


Metabolism and nutritional disorders



Blood and lymphatic system disorders

Haemolytic anaemia, blood dyscrasias


Musculoskeletal and connective tissue disorders

Muscle twitching, muscle weakness


Psychiatric disorders

Confusion*, excitation*, irritability*, nightmares*, depression


Renal and urinary disorders

Urinary retention


Skin and subcutaneous disorders

Exfoliative dermatitis, rash, urticaria, photosensitivity


Respiratory, thoracic and mediastinal disorders

Thickening of bronchial secretions


Vascular disorders



Hepatobiliary disorders

Hepatitis, including jaundice


Ear and labyrinth disorders



Cardiac disorders

Palpitations, tachycardia, arrythmias


General disorders and administration site conditions



Chest tightness


*Children and the elderly are more likely to experience the neurological anticholinergic effects and paradoxical excitation (eg. increased energy, restlessness, nervousness).

Reporting of suspected adverse reactions

Reporting suspected adverse reactions after authorisation of the medicinal product is important. It allows continued monitoring of the benefit/risk balance of the medicinal product. Healthcare professionals are asked to report any suspected adverse reactions via the Yellow Card Scheme or search for MHRA Yellow Card in the Google Play or Apple App Store.

4.9 Overdose

Symptoms and signs

The estimated lethal dose of chlorphenamine is 25 to 50mg/kg body weight. Symptoms and signs include sedation, paradoxical excitation of the CNS, toxic psychosis, convulsions, apnoea, anticholinergic effects, dystonic reactions and cardiovascular collapse including arrhythmias.


Management should be as clinically indicated or as recommended by the national poisons centres where available.

Symptomatic and supportive measures should be provided with special attention to cardiac, respiratory, renal and hepatic functions and fluid and electrolyte balance. If overdosage is by the oral route, treatment with activated charcoal should be considered provided there are no contraindications for use and the overdose has been taken recently (treatment is most effective if given within an hour of ingestion). Treat hypotension and arrhythmias vigorously. CNS convulsions may be treated with i.v. diazepam. Haemoperfusion may be used in severe cases.

5. Pharmacological properties
5.1 Pharmacodynamic properties

ATC Code R06AB02

Chlorphenamine is a potent antihistamine (H1-antagonist).

Antihistamines diminish or abolish the actions of histamine in the body by competitive reversible blockade of histamine H1-receptor sites on tissues. Chlorphenamine also has anticholinergic activity.

Antihistamines act to prevent the release of histamine, prostaglandins and leukotrienes and have been shown to prevent the migration of inflammatory mediators. The actions of chlorphenamine include inhibition of histamine on smooth muscle, capillary permeability and hence reduction of oedema and wheal in hypersensitivity reactions such as allergy and anaphylaxis.

5.2 Pharmacokinetic properties

Chlorphenamine is well absorbed from the gastro-intestinal tract, following oral administration. The effects develop within 30 minutes, are maximal within 1 to 2 hours and last 4 to 6 hours. The plasma half-life has been estimated to be 12 to 15 hours.

Chlorphenamine is metabolised to the monodesmethyl and didesmethyl derivatives. About 22% of an oral dose is excreted unchanged in the urine.

5.3 Preclinical safety data

No additional data of relevance.

6. Pharmaceutical particulars
6.1 List of excipients


Maize Starch

Yellow Iron Oxide (E172)

Magnesium Stearate

Purified Water

6.2 Incompatibilities

None reported.

6.3 Shelf life

3 years.

6.4 Special precautions for storage

Do not store above 30° C

6.5 Nature and contents of container

The tablets are supplied in securitainers containing 50 or 500 tablets or blister packs containing 30, 45, 60 or 100 tablets

6.6 Special precautions for disposal and other handling

For detailed instructions for use refer to the Patient Information Leaflet in every pack.

7. Marketing authorisation holder

Haleon UK Trading Limited

The Heights



KT13 0NY

United Kingdom

8. Marketing authorisation number(s)

PL 44673/0092

9. Date of first authorisation/renewal of the authorisation

14/02/1997 / 27/10/2005

10. Date of revision of the text

14th April 2023

Haleon UK Trading Limited
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The Heights, Weybridge, Surrey, KT13 0NY, UK
Medical Information Direct Line
0800 783 8881
Medical Information e-mail
[email protected]
Customer Care direct line
0800 783 8881