Histacin (Chlorpheniramine Maleate): A Sedating Antihistamine

Histacin contains Chlorpheniramine Maleate, an alkylamine antihistamine. It is a potent histamine H1-receptor blocking agent used to treat various allergic conditions. It generally causes less sedation than some other antihistamines, like promethazine. Histacin is indicated for conditions such as urticaria, sensitivity reactions, angioneurotic edema, and the common cold. It is a sedating antihistamine.

How Histacin Works (Pharmacology)

Chlorpheniramine Maleate works by blocking histamine receptors:

• H1-receptor Blocker: It acts as a potent and competitive antagonist of the histamine H1-receptor.
• Blocks Histamine Effects: By blocking these receptors, it prevents histamine—a compound involved in allergic reactions—from causing its effects, such as itching, swelling, and sneezing.

Key Indications & Benefits

Histacin is indicated for the following conditions:

• Urticaria (hives) and other sensitivity reactions.
• Angioneurotic edema.
• Vasomotor rhinitis.
• Symptoms of the common cold, such as cough.
• Motion sickness.
• Other allergic conditions.

Dosage & Administration

The dosage of Histacin varies by age. Always consult a registered physician for specific dosage instructions.

• Adults: 4 mg every 4-6 hours. The maximum daily dose is 24 mg.
• Children 6-12 years: 2 mg every 4-6 hours. The maximum daily dose is 12 mg.
• Children 2-5 years: 1 mg every 4-6 hours. The maximum daily dose is 6 mg.
• Children 1-2 years: 1 mg twice daily.
• Children under 1 year: Use is not recommended.

Important Considerations & Warnings

It is crucial to discuss your full medical history with your doctor before taking Histacin.

Contraindications:

• Hypersensitivity to Chlorpheniramine.
• Newborn or premature infants.

Side Effects:

• Common: Drowsiness, dizziness, muscular weakness, and gastrointestinal upset.
• Overdose: Can lead to CNS depression or stimulation, blurred vision, dizziness, hypotension, and in children, atropine-like signs and symptoms.

Pregnancy & Lactation:

• Pregnancy: This drug should not be used in pregnant women, especially during the first trimester.
• Lactation: It should not be used in lactating mothers.

Precautions & Warnings:

• Underlying Conditions: Use with caution in patients with glaucoma and prostatic hypertrophy.
• Daily Activities: Caution should be taken when driving vehicles or operating machinery due to potential drowsiness and dizziness.

Drug Interactions:

• Incompatible with: Calcium chloride, kanamycin sulfate, noradrenaline acid tartrate, pentobarbital sodium, and meglumine adipiodone.

Overdose Effects

• Symptoms: CNS depression (sedation, apnea, cardiovascular collapse), or CNS stimulation (insomnia, tremors, convulsions). Other symptoms can include tinnitus, blurred vision, and dizziness.
• Children: More likely to show stimulation and atropine-like symptoms, such as dry mouth and dilated pupils.

Storage Conditions

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