Chlorpheniramine Maleate | Piriton

Chlorphenamine maleate BP 4 mg              

Chlorphenamine maleate BP 4 mg

Chlorphenamine Maleate is a potent antihistamine (H1-receptor antagonist) and acts by blocking the action of histamine in the body by competitive reversible blockade of histamine H1-receptor sites on tissues. Thereby mediates the contraction of smooth muscle and the dilation and increased permeability of the capillaries and hence reduction of oedema and wheal in hypersensitivity reactions such as allergy and anaphylaxis.

Chlorphenamine Therapeutic Indications

To relieve the symptoms of allergic conditions such as hay fever (seasonal allergic rhinitis), urticaria, pruritis, food allergy, drug and serum reactions, insect bite or sting reactions, allergies to foods or medicines and angioneurotic oedema.

Chlorphenamine Posology and Method of Administration

Do not exceed the stated dose or frequency of dosing.

Adults and children over 12 years: 1 tablet 4 to 6 hourly. Maximum daily dose: 6 tablets (24mg in total) 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 3 tablets (12mg in total) in any 24 hours, taken 1 tablet 4 to 6 hourly


Children aged 6-12 years: ½ tablet 4 to 6 hourly. Maximum daily dose: 3 tablets (l2 mg in total) in any 24 hours.

Not recommended for children under the age of 6 years.

Chlorphenamine Contraindications

  • Hypersensitivity to chlorphenamine or to any of the excipients.
  • Hypersensitivity to antihistamines.
  • Patients in coma or patients with brain damage.
  • Patients on monoamine oxidase inhibitor therapy within the previous 14 day.

Chlorphenamine Special Warnings and Special Precautions for Use

Use with caution in epilepsy, raised intra-ocular pressure including glaucoma, prostatic hypertrophy; severe hypertension or cardiovascular disease, thyrotoxicosis, urinary retention, bronchitis, bronchiectasis or asthma, hepatic impairment.

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

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.

Chlorphenamine Special Risk Patients

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.

Pregnancy: Category B: Safety for use during pregnancy has not been established.

Lactation: May inhibit lactation and may be secreted in breast milk. Not to be used during lactation unless considered essential by a physician.

Chlorphenamine Interaction with other medicinal products and other forms of interaction

Chlorphenamine inhibits phenytoin metabolism and can lead to phenytoin toxicity. Alcohol potentiates sedation due to chlorphenamine.

The risk of antimuscarinic side effects is increased when antihistamines are given with antimuscarinics.

Antidepressants increase the sedative and antimuscarinic effects of anti-histamines.

Concurrent use of chlorphenamine and hypnotics or anxiolytics may cause an increase in sedative effects.

The anticholinergic effects of chlorphenamine are intensified by MAOIs

Lopinavir may increase the plasma concentration of chlorphenamine.

Chlorphenamine Pregnancy and Lactation

Pregnancy: Category B: Safety for use during pregnancy has not been established.

Lactation: May inhibit lactation and may be secreted in breast milk. Not to be used during lactation unless considered essential by a physician

Chlorphenamine Effects on ability To Drive and use Machines

Not Applicable

Chlorphenamine Undesirable Effects

Adverse reactions which have been observed in clinical trials and which are considered to be common (occurring in > 1% to < 10% of subjects) or very common (occurring in 10 % of subjects) are listed below:

Cardiac disorders: Unknown: palpitation, tachycardia, arrhythmias.

Blood and lymphatic system disorders: Unknown: haemolytic anaemia and other blood dyscrasias

Nervous system disorders: Very common: sedation varying from slight drowsiness to deep sleep, somnolence; Common: dizziness, headaches and concentration ability impaired, incoordination

Eye disorders: Common: blurred vision

Ear and labyrinth disorders: Unknown: tinnitus

Respiratory, thoracic and mediastinal disorders: Unknown: increased viscosity (thickening) of bronchial secretions

Gastrointestinal disorders: Common: nausea, dry mouth; Uncommon: vomiting, diarrhoea, abdominal pain, dyspepsia and anorexia;

Renal and urinary disorders: Unknown: urinary retention

Skin and subcutaneous tissue disorders: Unknown: exfoliative dermatitis, photosensitivity and skin reactions such as urticaria

Musculoskeletal and connective tissue disorders: Unknown: twitching and muscular weakness.

Vascular disorders: Unknown; hypotension

General disorders and administration site conditions: Common: lassitude; uncommon: dizziness, tightness of chest and irritability

Hepatobiliary disorders: Unknown: hepatitis, including jaundice

Psychiatric disorders: Unknown: depression and nightmares. Paradoxical excitation in children and confusional psychosis in the elderly can occur.

Chlorphenamine Overdose

Estimated lethal dose of Chlorphenamine is 25-50 mg/kg bodyweight.

Symptoms and signs include sedation, paradoxical stimulation of CNS, toxic psychosis, seizures, apnoea, convulsions, anticholinergic effects, dystonic reactions and cardiovascular collapse including arrhythmias.


Treatment includes gastric lavage or emesis using syrup of ipecac. Following these measures activated charcoal and cathartics may be administered to minimize absorption.

Other symptomatic and supportive measures should be provided with special attention to cardiac, respiratory, renal and hepatic functions and fluid and electrolyte balance.

Treat hypotension and arrhythmias vigorously. CNS convulsions may be treated with IV diazepam or phenytoin. Hemoperfusion may be used in severe cases.


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