SENSITAMINE Tablet

1. Symptomatic treatment of perennial and seasonal allergic rhinitis, vasomotor rhinitis and allergic conjunctivitis due to inhalant allergens and foods.

2. Symptomatic treatment of pruritus associated with allergic reactions and of mild, uncomplicated allergic skin manifestation of urticaria and angioedema and in dermatographism.

3. May be used in combination with a decongestant (Pseudoephedrine) for the temporary relief of nasal and sinus congestion associated with the common cold and allergic rhinitis.

Dosage

Usual adult dose - Oral, 4mg every 4-6 hours as needed.

Usual adult prescribing limit - Up to 24mg daily.

Usual paediatric dose - Children up to 6 years of age: use is not recommended.

Children 6-12 years: Oral, 2mg, 3-4 time a day as needed; not to exceed 12mg/day.

In newborn and premature infants, during lactation, as treatment for asthma, in patients on monoamine oxidase (MAO) inhibitors.

Cross sensitivity

Patients intolerant of one antihistamine may be intolerant of other antihistamines.

Sedation, mild as compared to promethazine; Gastrointestinal disturbances - nausea, epigastric pain, and rarely vomiting, diarrhoea or constipation; Blurred vision or changes in vision, confusion and dizziness are less common; Dryness of mouth, nose or throat and difficulty in micturation due to anticholinergic effect may also occur; Loss of appetite; Increased skin sensitivity to sunlight; Blood dyscrasias (rare); Thickening of mucous, fast heartbeat, paradoxical reactions (nightmares, unusual excitement, nervousness, restlessness or irritability) ringing or buzzing in the ears and skin rash

1. Alcohol and CNS depression - producing medications - may potentiate the CNS depressant effects.

2. Anticholinergics or other medication with anticholinergic activity (including maprotiline and tricyclic antidepressant) - anticholinergic effects may be potentiated.

3. Ototoxic medications - symptoms of ototoxicity such as tinnitus, dizziness or vertigo may be masked.

4. Photosensitizing medications - concurrent use with antihistamine may cause additive photosensitizing effects.

5. Phenytoin - chlorpheniramine inhibits phenytoin metabolism and can lead to phenytoin toxicity.

Pregnancy / reproduction

Safety for the use of Chlorpheniramine Maleate during pregnancy has not been established, it should only be used during pregnancy when clearly needed and when potential benefits outweigh the potential unknown risks of the foetus. Use during third trimester may result in reactions in the newborn or premature neonates.

Breast-feeding

Small amounts of antihistamines are excreted in breast milk, use is not recommended in nursing mothers because of the risk of adverse effects, such as usual excitement or irritability of antihistamines in infants.

Antihistamines may inhibit lactation because of their antimuscarinic action.

All antihistamine given in effective dosage, may cause dizziness or drowsiness. In consequence, until the effect of treatment is known, patients treated with chlorpheniramine should be warned not to take change of vehicles or machinery. The sedative action of alcohol may be potentiated by antihistamines so that drowsiness can occur in patients not otherwise subjected to it if alcohol is taken.

Risk-benefit must be considered when the following medical problems exist: bladder neck obstruction, prostatic hypertrophy (symptomatic), urinary retention, angle closure glaucoma (or predisposition to), open angle glaucoma or sensitivity to chlorpheniramine maleate.

Paediatrics: Use is not recommended in newborn and premature infants because this age group has an increased susceptibility to anticholinergic side effects, such as central nervous system (CNS)excitation, and an increased tendency towards convulsion. A paradoxical reaction characterized by hyper excitability may occur in older children taking antihistamines.

Geriatric: Dizziness, sedation, confusion and hypotension may be more likely to occur in geriatric patients taking antihistamines. A paradoxical reaction characterized by hyper excitability may occur in geriatric patients taking antihistamines. Geriatric patients are especially susceptible to the anticholinergic side effects, such as dryness of mouth and urinary retention (especially in males), of the antihistamines If these side effects occur ad continue or severe, medication should probably be discontinued.

Dental: Prolonged use of antihistamines may decrease or inhibit salivary flow, thus contributing to the development of caries, periodontal disease, oral candidiasis and discomfort.

Antihistamine used in the treatment of allergy acts by competing with histamine for H1-receptor sites of effector cells. It thereby prevents but does not reverse, responses mediated by histamine alone. The relationship between chemical structure and antihistamine activity is highly complex, but most of the antihistamines have the core structure of ethylamine -CH2-CH2N= which is also present in histamine. The antimuscarinic actions of most antihistamines provide a drying effect on the nasal mucosa.