Chlorantine-M (Chlorpheniramine): Uses, Side Effects, and Warnings

1. Disclaimer

We do not guarantee the accuracy, currency or completeness of information regarding medications or medical products, and official sources should be verified before making any decisions. By using this blog, you agree to assume personal responsibility for relying on the information provided.

This content is intended for educational and professional reference only and does not replace official prescribing information, regulatory approvals, or clinical judgment of qualified healthcare professionals.

2. Summary

Chlorantine-M is a brand of chlorpheniramine maleate, a first-generation H1-antihistamine (alkylamine class) used for the symptomatic relief of allergic conditions. While sometimes described in older promotional materials as having “minimum sedation,” contemporary pharmacological evidence confirms that sedation and anticholinergic effects are expected, though they may be less pronounced than with some other first-generation antihistamines. The drug provides effective relief of histamine-mediated symptoms but is not disease-modifying and not indicated for asthma control.

3. Brand Name

Chlorantine-M

4. Category

• Pharmacological class: First-generation H1-receptor antagonist (alkylamine derivative)
• Therapeutic class: Antihistamine / Antiallergic agent

5. Active Ingredient

Chlorpheniramine maleate

6. Pharmaceutical Form & Strength

Oral tablets

• Strength: 4 mg chlorpheniramine maleate per tablet
• Typical pack size: 20 tablets (market-specific)

7. Manufacturer & Marketing Authorization Holder

Misr Company for Pharmaceutical Industries S.A.E. (MISR) Cairo, Egypt

Note: Current marketing authorization status and package insert should be verified with the Egyptian Drug Authority (EDA).

8. Mechanism of Action

Chlorpheniramine is an inverse agonist at histamine H1 receptors, competitively inhibiting histamine-mediated effects such as vasodilation, increased capillary permeability, itching, and sneezing. It readily crosses the blood–brain barrier, resulting in central nervous system (CNS) effects, including sedation. It also exhibits anticholinergic (antimuscarinic) activity, contributing to both therapeutic effects and adverse reactions.

9. Spectrum of Activity

Limited to histamine-mediated (Type I hypersensitivity) allergic symptoms. It has no antimicrobial, antiviral, or anti-inflammatory spectrum beyond H1-receptor blockade.

10. Pharmacokinetics

• Absorption: Well absorbed orally; bioavailability reduced by first-pass hepatic metabolism
• Onset of action: ~30 minutes
• Peak plasma levels: 2–6 hours
• Distribution: Widely distributed; crosses the blood–brain barrier and placenta; ~70% protein bound
• Metabolism: Extensive hepatic metabolism, mainly via CYP2D6
• Elimination half-life: Approximately 20–24 hours (high inter-individual variability)
• Excretion: Primarily renal (metabolites and small amounts unchanged)

11. Indications

Evidence-based indications include symptomatic relief of:

• Allergic rhinitis (hay fever)
• Urticaria
• Allergic conjunctivitis
• Pruritus of allergic origin (including insect bites and stings)
• Atopic dermatitis and eczema (adjunctive, symptomatic relief)

Not indicated for the treatment or control of asthma or acute asthmatic attacks.

12. Administration

• Route: Oral
• Typical adult dose: 4 mg every 4–6 hours as needed
• Maximum daily dose: Up to 24 mg/day (depending on labeling and clinical judgment)

Exact dosing should follow the current official product leaflet.

13. Method of Preparation

Not applicable (ready-to-use tablet; no reconstitution required).

14. Contraindications

• Hypersensitivity to chlorpheniramine or formulation components
• Narrow-angle glaucoma
• Urinary retention, bladder neck obstruction, or symptomatic prostatic hypertrophy
• Pyloroduodenal or peptic ulcer obstruction
• Concomitant use with, or within 14 days of, MAO inhibitors
• Newborns and premature infants

15. Warnings & Precautions

• Sedation and impaired alertness are common; caution with driving or operating machinery
• Anticholinergic effects (dry mouth, constipation, urinary retention), especially in elderly patients
• Use with caution in patients with asthma or chronic bronchitis (may thicken secretions)
• Increased risk of confusion, falls, and cognitive impairment in older adults
• Avoid alcohol and other CNS depressants

16. Drug Interactions

• MAO inhibitors: Prolonged and intensified anticholinergic and CNS effects (contraindicated)
• CNS depressants: Additive sedation (alcohol, opioids, benzodiazepines, sedative hypnotics)
• Anticholinergic drugs: Increased anticholinergic burden (e.g., TCAs)
• CYP2D6 inhibitors (e.g., fluoxetine, paroxetine): May increase chlorpheniramine exposure

17. Side Effects

Common:

• Drowsiness, dizziness
• Dry mouth, nose, or throat
• Blurred vision

Less common:

• Gastrointestinal discomfort, constipation
• Urinary retention

Rare/serious:

• Confusion (especially elderly)
• Paradoxical excitation (children)
• Arrhythmias or seizures (mainly in overdose)

18. Use in Special Populations

• Pregnancy: Use only if benefit outweighs risk; avoid routine use, especially late pregnancy
• Lactation: Excreted in breast milk; may cause infant sedation or irritability—generally avoid
• Pediatrics: Not recommended in infants; careful dosing and monitoring in children
• Elderly: Use with caution or avoid due to high anticholinergic and sedative risk
• Hepatic/Renal impairment: Caution advised; dose adjustment may be required

19. Storage Conditions

• Store below 30°C, protected from moisture and light.
• Keep out of reach of children.

20. Additional Sections

Clinical Consideration:

Although effective, first-generation antihistamines like chlorpheniramine are increasingly replaced by second-generation agents due to improved safety profiles. Chlorantine-M remains in use in some markets due to availability and cost.

21. Frequently Asked Questions (FAQ)

Q1: Does Chlorantine-M really cause minimal sedation? A: Sedation is common. Claims of “minimum sedation” are based on outdated comparisons and should not be relied upon clinically.

Q2: Can it be used for asthma? A: No. It does not treat asthma and should not be used during acute attacks.

Q3: How long does one dose last? A: Symptomatic relief usually lasts 4–6 hours with immediate-release tablets.

22. References

1. AHFS Drug Information – Antihistamines
2. Lexicomp Drug Monograph: Chlorpheniramine
3. DrugBank: Chlorpheniramine Maleate
4. DailyMed (NIH): Chlorpheniramine labeling
5. Martindale: The Complete Drug Reference
6. Manufacturer historical leaflet (Misr Pharmaceuticals – product-specific, unverified)