Histal Syrup - (2mg/5ml) contains Chlorpheniramine Maleate BP 2 mg per 5 ml. It is manufactured by Opsonin Pharma Limited in Bangladesh.

Indications:

Histal Syrup is a sedating antihistamine primarily used for the symptomatic relief of various allergic conditions, including:

• Allergic Rhinitis: Hay fever (seasonal allergic rhinitis) and perennial allergic rhinitis (year-round allergies), characterized by sneezing, runny nose, and watery eyes.
• Allergic Conjunctivitis: Inflammation of the conjunctiva (eye membrane) due to allergens, causing itching and redness.
• Urticaria (Hives) and Angioedema: Skin reactions characterized by itchy welts or swelling beneath the skin.
• Pruritic Skin Disorders: Conditions involving intense itching, such as eczema, atopic dermatitis, and insect bites.
• Vasomotor Rhinitis: Non-allergic rhinitis with symptoms similar to allergies.
• Cough and Common Cold Symptoms: Can help alleviate sneezing, runny nose, and watery eyes associated with colds.
• Motion Sickness: Can help prevent or relieve nausea and vomiting associated with motion.
• As an adjunct in the emergency treatment of anaphylactic reactions (severe allergic reactions), once acute symptoms have been managed.

Pharmacology:

Chlorpheniramine Maleate is a first-generation alkylamine antihistamine. It works by competitively blocking histamine H1-receptors on effector cells in the gastrointestinal tract, blood vessels, and respiratory tract. By blocking these receptors, it prevents the action of histamine, a chemical mediator released during allergic reactions, thereby reducing allergic symptoms like itching, sneezing, and swelling. It also has weak anticholinergic (drying) effects, which can help with runny nose and watery eyes, and moderate sedative properties.

Dosage and Administration (Oral):

Histal Syrup can be taken by adults and children. Always follow the dosage instructions given by your physician or as provided on the product leaflet. It can be taken with or without food.

• Adults and Children (12 years and above): 10 ml (2 teaspoonfuls) every 4-6 hours. The maximum daily dose is 24 mg (60 ml or 12 teaspoonfuls) in 24 hours.
• Children 6-11 years: 5 ml (1 teaspoonful) every 4-6 hours. The maximum daily dose is 12 mg (30 ml or 6 teaspoonfuls) in 24 hours.
• Children 2-5 years: 2.5 ml (½ teaspoonful) every 4-6 hours. The maximum daily dose is 6 mg (15 ml or 3 teaspoonfuls) in 24 hours.
• Children 1-2 years: 2.5 ml (½ teaspoonful) twice daily.
• Children under 1 year: The use of Chlorpheniramine Maleate is generally not recommended without strict medical supervision.

Contraindications:

Histal Syrup is contraindicated in:

• Patients with known hypersensitivity to Chlorpheniramine Maleate or any other component of the syrup.
• Newborn or premature infants.
• Patients experiencing an acute asthmatic attack.
• Patients with narrow-angle glaucoma.
• Patients with prostatic hypertrophy (enlarged prostate) causing urinary retention.
• Patients with stenosing peptic ulcer or pyloroduodenal obstruction.
• Concurrent use with Monoamine Oxidase Inhibitors (MAOIs) or within 14 days of stopping MAOIs.

Side Effects:

Common side effects of Histal Syrup include:

• Drowsiness/Sedation (most common, especially with higher doses or in sensitive individuals).
• Dizziness, lightheadedness.
• Dryness of mouth, nose, and throat.
• Gastrointestinal upset (e.g., nausea, vomiting, abdominal pain, constipation, or diarrhea).
• Blurred vision.
• Headache.
• Nervousness, restlessness, or insomnia (paradoxical excitation, particularly in children).
• Difficulty with urination.

Precautions and Warnings:

• CNS Depression: May cause significant drowsiness. Patients should avoid driving or operating hazardous machinery until they know how the medication affects them.
• Alcohol: Concomitant consumption of alcohol or other central nervous system (CNS) depressants (e.g., sedatives, tranquilizers, opioids) should be avoided as it can enhance drowsiness.
• Underlying Conditions: Use with caution in patients with glaucoma, prostatic hypertrophy, urinary retention, epilepsy, hyperthyroidism, cardiovascular disease, or liver disease.
• Children and Elderly: Children, especially young ones, and elderly patients may be more susceptible to side effects, including paradoxical excitement or increased drowsiness/confusion, respectively.
• Allergy Testing: Antihistamines should be discontinued several days before allergy skin tests, as they can interfere with the results.

Pregnancy and Lactation:

• Pregnancy: The safety of chlorpheniramine during pregnancy has not been definitively established. It is generally not recommended, especially during the first trimester, unless clearly indicated by a physician after a careful risk-benefit assessment.
• Lactation: Chlorpheniramine is excreted in small amounts in breast milk. Due to the potential for adverse effects (e.g., sedation) in the infant, it is generally recommended to avoid breastfeeding while taking this medication, or to consult a doctor.

Drug Interactions:

• CNS Depressants: Enhanced sedative effect when taken with alcohol, hypnotics, sedatives, tranquilizers, anxiolytics, and opioid analgesics.
• Monoamine Oxidase Inhibitors (MAOIs): MAOIs can prolong and intensify the anticholinergic and CNS depressant effects of antihistamines. Concurrent use is contraindicated.
• Anticholinergic Drugs: Concurrent use with other anticholinergic medications (e.g., some antidepressants, antipsychotics) may lead to increased anticholinergic side effects such as dry mouth, blurred vision, and urinary retention.
• Certain antibiotics (e.g., Kanamycin sulfate) or other agents (e.g., Calcium chloride, Noradrenaline acid tartrate, Pentobarbital sodium, Meglumine adipiodone): Chlorpheniramine maleate has been reported to be incompatible with these in some contexts, but this mostly refers to parenteral (injection) formulations.

Storage Conditions:

Store in a cool (below 25°C) and dry place, protected from light. Keep out of the reach of children.

Note: This information is for general knowledge and informational purposes only and does not substitute professional medical advice. Always consult your doctor or pharmacist for specific instructions and guidance regarding your medication.