Histerzin 5 mg/5 ml (Oral Solution)

Indications

• Potent long-acting antihistamine with additional anti-emetic and sedative/calming effects.
• Indicated in symptomatic treatment of allergic conditions of the respiratory tract and skin.
• Sensitization reactions to drug or foreign proteins, anaphylactic reactions.
• For sedation, allergic rhinitis, urticaria and insomnia.
• As an adjunct in pre-operative sedation in surgery and obstetrics.
• As a paediatric sedative

Pharmacology

• Blocks postsynaptic mesolimbic dopaminergic receptors in the brain
• Exhibits strong α-adrenergic blocking effect
• Depresses the release of hypothalamic and hypophyseal hormones
• Competes with histamine for the H1-receptor
• Reduces stimuli to the brainstem reticular system
• Well absorbed from the gastrointestinal tract

Dosage & Administration

• Initial dose one 25 mg tablet at night for adults
• May be increased to two or three 25 mg tablets at night if necessary for adults
• No specific dosage recommendations for the elderly
• Children may be treated more conveniently by the elixir containing 5 mg/5 ml
• Children of 2-5 years: 5-15 mg as an antihistamine in allergy
• Children of 5-10 years: 10-25 mg as an antihistamine in allergy
• Children of 2-5 years: 15-20 mg as a sedative
• Children of 5-10 years: 20-25 mg as a sedative

Interaction

• Histerzin may enhance the action of any anticholinergic agent, tricyclic antidepressant, sedative or hypnotic
• Alcohol should be avoided during drug treatment
• May interfere with immunologic urine pregnancy tests to produce false-positive or false-negative results
• Should be discontinued at least 72 hours before the start of skin tests using allergen extracts as it may inhibit the cutaneous histamine response thus producing false-negative results

Contraindications

• Contraindicated for use in children less than two years of age
• Hypersensitivity to promethazine or to any of the excipients
• Should not be used in patients who are in a coma or suffering from CNS depression of any cause
• Must not be given to neonates or premature infants
• Should be avoided in patients who have been taking monoamine oxidase inhibitors within the previous 14 days

Side Effects

• Neuroleptic Malignant Syndrome
• Anticholinergic effects and confusion
• Somnolence
• Dizziness
• Headaches
• Extrapyramidal effects including muscle spasm, tic-like movements of the head and face
• Allergic reactions including urticaria, rash, pruritus, and anaphylaxis
• Photosensitivity reaction
• Anorexia
• Epigastric discomfort
• Dry mouth
• Blurred vision
• Blood dyscrasias including hemolytic anemia, agranulocytosis
• Urinary retention
• Infants, newborns and premature are susceptible to the anticholinergic effects of promethazine
• Paradoxical hyperexcitability, restlessness, nightmares, disorientation
• Palpitations
• Arrhythmias
• Hypotension
• Jaundice
• Tiredness

Pregnancy & Lactation

• Epidemiological evidence for the safety of promethazine in pregnancy
• Animal studies have shown no hazard
• Not recommended in the two weeks prior to delivery in view of the risk of irritability and excitement in the neonate
• Prolonged neurological disturbances in the infant when given in high doses during late pregnancy
• Excreted in breastmilk
• Risks of neonatal irritability and excitement

Precautions & Warnings

• Avoid in children and adolescents with signs and symptoms suggestive of Reye’s syndrome
• May thicken or dry lung secretions and impair expectoration
• Use with caution in patients with asthma, bronchitis, or bronchiectasis
• Use with care in patients with severe coronary artery disease
• Use with care in patients with narrow angle glaucoma
• Use with care in patients with epilepsy
• Use with care in patients with hepatic insufficiency
• Use with care in patients with renal insufficiency
• Caution should be exercised in patients with bladder neck obstruction
• Caution should be exercised in patients with pyloro-duodenal obstruction

Overdose Effects

• Symptoms of severe overdose are variable
• Characterised in children by various combinations of excitation, ataxia, incoordination, athetosis, and hallucinations
• Adults may become drowsy and lapse into coma
• Convulsions may occur in both adults and children
• Tachycardia may develop
• Cardiorespiratory depression is uncommon
• Induce vomiting with ipecacuanha despite the antiemetic effect of promethazine
• Gastric lavage may be used
• Convulsions should be treated with diazepam or other suitable anticonvulsant

Therapeutic Class

• Anti-emetic drugs
• Miscellaneous sedatives & hypnotics
• Sedating Anti-histamine

Storage Conditions

• Protect from light
• Do not use later than the date of expiry
• Keep all medicines out of the reach of children
• To be dispensed only on the prescription of a registered physician

Related Brands

• Allphen 5 mg/5 ml (Oral Solution) - medimet-pharmaceuticals-ltd
• Flumin 5 mg/5 ml (Oral Solution) - cosmic-pharma-ltd
• Histaphen 5 mg/5 ml (Oral Solution) - seema-pharmaceuticals-ltd