1 Name of Medicine
Dexchlorpheniramine maleate.
2 Qualitative and Quantitative Composition
Each tablet contains dexchlorpheniramine maleate 2 mg.
List of excipients with known effects.
Lactose monohydrate.
For the full list of excipients, see Section 6.1 List of Excipients.3 Pharmaceutical Form
White, round, flat, uncoated tablets, scored on one side and plain on the other side.
4.1 Therapeutic Indications
For the symptomatic treatment of perennial and seasonal allergic rhinitis, vasomotor rhinitis, allergic conjunctivitis, mild uncomplicated allergic skin manifestations of urticaria and angioedema. It may relieve itching due to skin conditions such as allergic eczema, pruritus ani, pruritus vulvae, atopic dermatitis, contact dermatitis, insect bites, dermographism and drug reactions, including serum sickness.
4.2 Dose and Method of Administration
Dose.
Adults and children over 12 years.
One tablet every 6 hours.
After initial relief is obtained, dosage may be reduced to one tablet daily as required.
Method of administration.
To be taken orally. It can be taken before or after food.4.3 Contraindications
This medication is contraindicated for use in:
Children under 12 years of age.
Patients taking monoamine oxidase inhibitors (MAOIs) (see Section 4.5 Interactions with Other Medicines and Other Forms of Interactions).
Patients with a history of hypersensitivity to dexchlorpheniramine, to other drugs of similar chemical structure, or to any of the excipients listed in Section 6.1 List of Excipients.
4.4 Special Warnings and Precautions for Use
Identified precautions.
This medication may cause drowsiness and may add to the effects of alcohol. Drowsiness may continue the following day. Those affected should not drive or operate machinery; alcohol should be avoided.
This medication should be used with caution in patients with:
narrow-angle glaucoma;
stenosing peptic ulcer;
prostatic hypertrophy;
bladder neck obstruction;
pyloroduodenal obstruction;
cardiovascular disease including hypertension;
increased intraocular pressure;
hyperthyroidism;
renal or hepatic impairment;
seizures.
This medication may cause photosensitivity in some patients.
Use in the elderly.
The elderly may experience paradoxical excitation with dexchlorpheniramine maleate. In patients over 60 years of age, antihistamines may cause dizziness, sedation and hypotension. Also, they are more likely to have central nervous system (CNS) depressive side effects, including confusion.
Paediatric use.
Children may experience paradoxical excitation with dexchlorpheniramine maleate. In children this may cause excitability.
Effects on laboratory tests.
Antihistamines should be discontinued approximately 48 hours prior to skin testing procedures since these drugs may prevent or diminish otherwise positive reactions to dermal reactivity indicators.4.5 Interactions with Other Medicines and Other Forms of Interactions
The following interactions with this medication have been noted:
Central nervous system (CNS) depressants (alcohol, sedatives, opioid analgesics, hypnotics) may cause an increase in sedative effects of this medication.
Concomitant administration with tricyclic antidepressants (TCAs) may result in additive antimuscarinic activity.
Monoamine oxidase inhibitors (MAOIs) may prolong and intensify the anticholinergic and CNS depressive effects of some antihistamines and may cause a decrease in blood pressure.
Oral anticoagulants may have their actions decreased by antihistamines.
4.6 Fertility, Pregnancy and Lactation
Effects on fertility.
No data available.
(Category A)
Safety during pregnancy has not been established. This medication should be used during the first two trimesters of pregnancy only if clearly needed.
This medication should not be used in the third trimester of pregnancy because newborn and premature infants may have severe reactions to antihistamines.
This medication has been taken by a large number of pregnant women and women of childbearing age without any proven increase in the frequency of malformations or other direct or indirect harmful effects of on the foetus having been observed.
This medication is excreted in breast milk. Therefore, caution should be exercised when administered to nursing mothers.4.7 Effects on Ability to Drive and Use Machines
This medication may cause drowsiness. If affected do not drive a vehicle or operate machinery. Avoid alcohol.
4.8 Adverse Effects (Undesirable Effects)
Slight to moderate drowsiness is the most frequent side effect of dexchlorpheniramine maleate.
Other reported reactions associated with antihistamine therapy in general include:
General.
Urticaria, drug rash, anaphylactic shock, photosensitivity, excessive perspiration, chills, dryness of mouth, nose and throat.
Cardiovascular.
Hypotension, hypertension, headache, palpitations, tachycardia, extrasystoles.
Haematological.
Haemolytic anaemia, hypoplastic anaemia, thrombocytopenia, agranulocytosis.
Gastrointestinal.
Epigastric distress, anorexia, nausea, vomiting, diarrhoea, constipation.
Genitourinary.
Urinary frequency, difficult urination, urinary hesitation and retention, early menses.
Nervous system.
Sedation, dizziness, disturbed coordination, fatigue, confusion, restlessness, excitation, nervousness, tremor, irritability, insomnia, euphoria, paraesthesia, blurred vision, diplopia, vertigo, tinnitus, acute labyrinthitis, hysteria, neuritis, convulsions, lassitude, depression, inability to concentrate, dilated pupils, hypereflexia, hyporeflexia, xerostomia, hallucinations, appetite stimulation, anxiety, facial dyskinesias and seizures.
Respiratory.
Thickening of bronchial secretions, tightness of chest, wheezing, nasal stuffiness.
Reporting suspected adverse effects.
Reporting suspected adverse reactions after registration 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 at www.tga.gov.au/reporting-problems.4.9 Overdose
For information on the management of overdose, contact the Poisons Information Centre on 13 11 26 (Australia).
Manifestation.
Antihistamine overdosage effects may vary from central nervous system depression (apnoea, arrhythmias, cardiovascular collapse, cyanosis, diminished mental alertness, sedation) to stimulation (convulsions, hallucinations, insomnia or tremors) to death. Other signs and symptoms may be ataxia, blurred vision, dizziness, hypotension and tinnitus. Stimulation is particularly likely in children, as are atropine-like signs and symptoms (dry mouth; fixed, dilated pupils; flushing; gastrointestinal symptoms and hyperthermia).
Treatment.
Dialysis is of little value in antihistamine poisoning. Treatment of the signs and symptoms of an over dosage are symptomatic and supportive. Consider standard measures to remove any unabsorbed drug. There is no specific antidote. Measures to enhance excretion (urinary acidification, haemodialysis) are not recommended.5 Pharmacological Properties
5.1 Pharmacodynamic Properties
Mechanism of action.
Dexchlorpheniramine, the d-isomer of the racemic compound chlorpheniramine, is two times more active than chlorpheniramine. Dexchlorpheniramine does not prevent the release of histamine, but rather, competes with free histamine for binding at the H1-receptor sites, and competitively antagonises the effects of histamine on H1-receptors in the gastrointestinal tract, uterus, large blood vessels, and bronchial muscle. Blockade of H1-receptors also suppresses the formation of oedema, flare, and pruritus that result from histaminic activity. Since dexchlorpheniramine binds to central and peripheral H1-receptors, sedative effects are likely to occur. H1-antagonists are structurally similar to anticholinergic agents and therefore possess the potential to exhibit anticholinergic properties of varying degrees. They also have antipruritic effects. Dexchlorpheniramine has high antihistaminic activity, moderate anticholinergic effects and minimal sedative effects. The drug does not possess antiemetic properties.
Clinical trials.
No data available.
5.2 Pharmacokinetic Properties
The absorption, distribution, metabolism and elimination of dexchlorpheniramine have not been specifically described. However, since dexchlorpheniramine is the primary active isomer of the racemic compound chlorpheniramine, the pharmacokinetics of dexchlorpheniramine are likely to be similar to that of chlorpheniramine.
Absorption.
Dexchlorpheniramine is administered orally. H1-antagonists are generally well absorbed from the gastrointestinal tract. The onset of action of immediate release formulations of chlorpheniramine is about 30-60 minutes. The Cmax of chlorpheniramine occurs in about 2 hours, the maximum therapeutic effect in about 6 hours, and the duration of action lasts between 4-8 hours.
Distribution.
Protein binding is approximately 72%. Chlorpheniramine is widely distributed in body tissues and fluids, and it crosses the placenta and is excreted into breast milk.
Metabolism.
The metabolism of chlorpheniramine is extensive and rapid, first occurring in the gastric mucosa and then on first-pass through the liver, which may be saturable. N-dealkylation produces several metabolites, which are excreted in the urine along with the parent compound.
Excretion.
The half-life in healthy adults and children is 20-24 hours and 10-13 hours, respectively. Excretion rates are dependent on the pH of urine and urinary flow, with the rate decreasing as the pH rises and urinary flow decreases.
5.3 Preclinical Safety Data
Genotoxicity.
No data available.
Carcinogenicity.
No data available.6 Pharmaceutical Particulars
6.1 List of Excipients
Lactose monohydrate, maize starch, pre-gelatinised starch, magnesium stearate.
6.2 Incompatibilities
Incompatibilities were either not assessed or not identified as part of the registration of this medicine.
6.3 Shelf Life
In Australia, information on the shelf life can be found on the public summary of the Australian Register of Therapeutic Goods (ARTG). The expiry date can be found on the packaging.
6.4 Special Precautions for Storage
Store below 25°C. Protect from light.
6.5 Nature and Contents of Container
APOHealth Dexchlorpheniramine Allergy Relief tablets are available in PVC/PVDC/Aluminium foil blister packs of 20 or 40 tablets.
6.6 Special Precautions for Disposal
In Australia, any unused medicine or waste material should be disposed of by taking to your local pharmacy.
6.7 Physicochemical Properties
Chemical structure.
CAS number.
2438-32-6.7 Medicine Schedule (Poisons Standard)
Schedule 3 - Pharmacist Only Medicine.
Summary Table of Changes
