Usage
Chlorpheniramine Maleate + Sulphacetamide is primarily used for the treatment of bacterial ocular infections accompanied by allergic manifestations.
- Pharmacological Classification: This combination comprises a first-generation antihistamine (chlorpheniramine maleate) and a sulfonamide antibiotic (sulphacetamide).
- Mechanism of Action: Chlorpheniramine provides relief from allergy symptoms by blocking the action of histamine at H1 receptors. Sulphacetamide exerts its antibacterial effect by inhibiting bacterial folic acid synthesis, impeding bacterial growth and proliferation.
Alternate Names
While this exact combination may not have a universally recognized alternate name, the individual components are sometimes referred to as:
- Chlorpheniramine Maleate: Chlorphenamine, Dexchlorpheniramine
- Sulphacetamide: Sulfacetamide Sodium
Brand names vary depending on the manufacturer and region. Some examples (from provided sources) are: Bleph, Cetamide, Klaron, Borosulfa, Chloranicol-S, Zinbro-S, among others.
How It Works
- Pharmacodynamics (Chlorpheniramine): Competes with histamine for H1-receptor sites, reducing allergic symptoms like itching, redness, and swelling. It has sedative properties due to its ability to cross the blood-brain barrier.
- Pharmacokinetics (Chlorpheniramine): Well-absorbed orally. Metabolized in the liver, primarily via CYP450 enzymes. Excreted renally.
- Pharmacodynamics (Sulphacetamide): Inhibits dihydropteroate synthase, a bacterial enzyme crucial for folic acid synthesis, thereby hindering bacterial growth.
- Pharmacokinetics (Sulphacetamide): For ophthalmic use, primarily exerts local effects. Systemically absorbed sulphacetamide can undergo hepatic metabolism. It is cleared mainly through renal excretion.
- Mode of Action: The combination works through distinct mechanisms: Chlorpheniramine acts as a histamine H1-receptor antagonist. Sulphacetamide exerts its antibacterial effect via competitive inhibition of dihydropteroate synthase, thus interfering with bacterial folic acid synthesis.
Dosage
Standard Dosage
Adults:
- Ophthalmic Solution: 1-3 drops in the affected eye(s) every 2-3 hours initially, tapering the frequency as the condition improves.
- Ophthalmic Ointment: A small amount (approximately 1/2 inch ribbon) applied to the conjunctival sac(s) every 3-4 hours and at bedtime, reducing frequency with improvement.
- Oral (Chlorpheniramine component): 4 mg every 4-6 hours, not exceeding 24 mg/day. Extended-release formulations are also available (8-12 mg every 8-12 hours).
Children:
- Ophthalmic: Sulphacetamide ophthalmic preparations are generally safe for children above two months of age. The dosage is similar to that of adults, but always refer to specific product guidelines or consult a pediatrician for precise recommendations.
- Oral (Chlorpheniramine component): Safety and efficacy not established for children under 2 years old. Children aged 2 to 6 years can be given 1 mg every 4-6 hours, not to exceed 6 mg/day. Children aged 6-12 years: 2 mg every 4-6 hours, not to exceed 12 mg/day. Children over 12: Adult doses apply.
Special Cases:
- Elderly Patients: Start with lower chlorpheniramine doses (e.g., 4 mg once or twice daily, or 8 mg at bedtime for sustained-release) due to increased sensitivity to anticholinergic effects. Monitor for confusion, dry mouth, constipation. Sulphacetamide dosage adjustment is typically not necessary.
- Patients with Renal Impairment: Chlorpheniramine dose adjustments may be needed. Sulphacetamide dosage adjustments are not usually needed, unless severe renal impairment exists. Monitor kidney function.
- Patients with Hepatic Dysfunction: Exercise caution with chlorpheniramine; dose reduction might be necessary. Closely monitor liver function.
Clinical Use Cases Clinical use cases primarily involve ocular infections with an allergic component. The combination is not typically used for systemic conditions requiring the listed clinical settings.
Dosage Adjustments Adjustments are made based on age, renal or hepatic function, and response to therapy.
Side Effects
Common Side Effects:
- Chlorpheniramine: Drowsiness, dizziness, dry mouth, blurred vision, constipation, nausea.
- Sulphacetamide (ophthalmic): Local irritation, stinging, burning, itching.
Rare but Serious Side Effects:
- Chlorpheniramine: Allergic reactions, confusion, difficulty urinating, irregular heartbeat, seizures.
- Sulphacetamide: Severe allergic reactions, Stevens-Johnson syndrome (rare).
Long-Term Effects: Generally not applicable for short-term ophthalmic use. Long term oral Chlorpheniramine may result in tolerance.
Contraindications
- Chlorpheniramine: Hypersensitivity, narrow-angle glaucoma, urinary retention, pyloroduodenal obstruction, acute asthma attack, MAOI use (within 14 days).
- Sulphacetamide: Sulfa allergy.
Drug Interactions
- Chlorpheniramine: Other CNS depressants (alcohol, sedatives, opioids), MAOIs, tricyclic antidepressants can potentiate sedative effects. Some antifungals, antibiotics (e.g., erythromycin, quinolones) may increase chlorpheniramine levels.
- Sulphacetamide: Silver-containing preparations (e.g., silver nitrate) are incompatible.
Pregnancy and Breastfeeding
- Chlorpheniramine: Not recommended during pregnancy, particularly the third trimester. Small, occasional doses may be acceptable during breastfeeding, but monitor the infant for drowsiness.
- Sulphacetamide (ophthalmic): Generally considered safe for both, however consult with a specialist regarding use.
Drug Profile Summary
- Mechanism of Action: Chlorpheniramine: H1-receptor antagonist; Sulphacetamide: Dihydropteroate synthase inhibitor.
- Side Effects: Drowsiness, dry mouth (chlorpheniramine); local irritation (sulphacetamide).
- Contraindications: Hypersensitivity, glaucoma, urinary retention (chlorpheniramine); sulfa allergy (sulphacetamide).
- Drug Interactions: CNS depressants, MAOIs (chlorpheniramine). Silver preparations (Sulphacetamide).
- Pregnancy & Breastfeeding: Consult specialist; monitor for adverse effects.
- Dosage: See detailed sections above.
- Monitoring Parameters: Observe eye for signs of infection resolution or adverse effects. Monitor for sedation, anticholinergic effects with chlorpheniramine.
Popular Combinations
Sulfacetamide is often combined with other antibiotics like neomycin and bacitracin for broader spectrum coverage.
Precautions
- Monitor for allergic reactions.
- Caution in patients with glaucoma, prostatic hypertrophy, asthma.
- Avoid alcohol with chlorpheniramine.
FAQs (Frequently Asked Questions)
Q1: What is the recommended dosage for Chlorpheniramine Maleate + Sulphacetamide?
A: See detailed dosage guidelines above. Dosages are adjusted based on age, formulation (solution or ointment), and the severity of the condition.
Q2: Can Chlorpheniramine Maleate + Sulphacetamide be used during pregnancy or breastfeeding?
A: Pregnant and breastfeeding women should consult a healthcare professional before using this combination.
Q3: What are the common side effects?
A: Common side effects include drowsiness, dry mouth, blurred vision, and local eye irritation.
Q4: What are the contraindications?
A: Contraindications include hypersensitivity to either component, glaucoma, urinary retention, and sulfa allergy.
Q5: Are there any drug interactions I should be aware of?
A: Yes, interactions can occur with CNS depressants, MAOIs, some antibiotics, and antifungals. Always check for potential interactions.
Q6: How does sulphacetamide work against bacterial infections?
A: Sulphacetamide inhibits bacterial folic acid synthesis, which is essential for bacterial growth.
Q7: Can this combination be used in children?
A: The ophthalmic preparation is generally safe for children above two months of age. The oral use of chlorpheniramine requires careful dosing adjustments based on age.
Q8: What should I do if a patient experiences an allergic reaction?
A: Discontinue use immediately and seek medical attention.
Q9: Can this be used for other allergic conditions besides eye infections?
A: This specific combination targets ocular infections. Oral chlorpheniramine can be used for other allergic conditions but the combination product is for ophthalmic use only.
