Usage
Chloramphenicol + Sulphacetamide is primarily prescribed for the treatment of superficial bacterial eye infections, such as conjunctivitis (pink eye) and blepharitis. Its pharmacological classification is antibiotic. The combination works by inhibiting bacterial protein synthesis (chloramphenicol) and interfering with bacterial folic acid synthesis (sulphacetamide), thereby halting bacterial growth.
Alternate Names
While the generic name is Chloramphenicol + Sulphacetamide, brand names may vary depending on the region. Some examples include Chloramphenicol and Sulfacetamide ophthalmic, Chloroptic-S, and others. It is often referred to simply as Chloramphenicol-Sulfacetamide.
How It Works
Pharmacodynamics: Chloramphenicol acts by binding to the 50S ribosomal subunit of bacteria, preventing protein synthesis and leading to bacteriostatic action. Sulphacetamide, a sulfonamide, competes with para-aminobenzoic acid (PABA) in the folic acid synthesis pathway, which is essential for bacterial growth. The combination exhibits broad-spectrum activity against various gram-positive and gram-negative ocular pathogens.
Pharmacokinetics: When administered topically as eye drops or ointment, Chloramphenicol + Sulphacetamide achieves high concentrations in ocular tissues. Systemic absorption is minimal, reducing the risk of systemic side effects. Chloramphenicol is metabolized by the liver, while sulfacetamide is primarily excreted unchanged in the urine. Some hepatic metabolism of sulfacetamide also occurs.
Mode of Action: Chloramphenicol targets the bacterial ribosome, specifically the 50S subunit. This binding interferes with peptide bond formation and inhibits protein synthesis. Sulphacetamide disrupts folic acid synthesis by mimicking PABA. Folic acid is essential for bacterial cell division and DNA replication.
Elimination Pathways: The primary elimination pathway for chloramphenicol is hepatic metabolism, while sulfacetamide is mostly excreted unchanged by the kidneys.
Dosage
Standard Dosage
Adults: Instill 1-2 drops of solution or apply a small amount (about 1/2 inch ribbon) of ointment into the affected eye(s) every 2-3 hours initially, then every 3-4 hours. For ointment, application at bedtime is also advised.
Children (≥2 months): Similar to adult dosing. Instill 1-2 drops of solution or apply a small amount (about 1/2 inch ribbon) of ointment into the affected eye(s) every 2-3 hours initially, then every 3-4 hours.
Special Cases:
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Elderly Patients: No specific dosage adjustments are typically necessary unless renal or hepatic impairment is present.
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Patients with Renal Impairment: Caution should be exercised, and dosage adjustment may be required for moderate to severe renal impairment due to the renal excretion of sulfacetamide.
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Patients with Hepatic Dysfunction: Use with caution in patients with severe hepatic impairment due to the metabolism of chloramphenicol and sulfacetamide. Dosage adjustments may be necessary.
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Patients with Comorbid Conditions: Careful monitoring is recommended for patients with a history of blood dyscrasias or bone marrow suppression, particularly with prolonged use.
Clinical Use Cases
The dosage for clinical use cases like intubation, surgical procedures, mechanical ventilation, ICU use, and emergency situations typically mirrors the standard adult dosage. However, the frequency of administration may be increased in some cases depending on the severity of infection and as directed by a healthcare professional.
Dosage Adjustments
Dosage adjustments should be made on a patient-specific basis and are based on renal function, hepatic function, and other relevant comorbidities. Close monitoring for adverse effects is essential.
Side Effects
Common Side Effects:
- Transient burning or stinging upon instillation
- Temporary blurred vision (particularly with ointment)
- Eye irritation or redness
Rare but Serious Side Effects:
- Bone marrow suppression (primarily with systemic chloramphenicol)
- Aplastic anemia (primarily with systemic chloramphenicol)
- Gray baby syndrome (in neonates with systemic chloramphenicol exposure)
- Stevens-Johnson syndrome
- Toxic epidermal necrolysis
- Severe allergic reactions (anaphylaxis), angioedema
Long-Term Effects:
- Potential for antibiotic resistance with prolonged use
- Secondary fungal infections
Adverse Drug Reactions (ADR):
- Severe allergic reactions (anaphylaxis)
- Angioedema
- Blood dyscrasias
Contraindications
- Hypersensitivity to chloramphenicol, sulphonamides, or any component of the formulation
- History of blood dyscrasias, especially with chloramphenicol
Drug Interactions
- Concurrent use with other topical ophthalmic medications should be approached cautiously. Allow sufficient time between applications if multiple ophthalmic medications are prescribed.
- Systemic antibiotics may interact with chloramphenicol if significant systemic absorption occurs.
- Potential interactions may occur with drugs metabolized by CYP450 enzymes.
- Alcohol should be avoided due to potential interactions.
Pregnancy and Breastfeeding
Pregnancy: Topical ophthalmic Chloramphenicol + Sulphacetamide is generally considered safe during pregnancy, although systemic absorption is minimal. However, systemic chloramphenicol should be avoided, particularly near term, due to the risk of gray baby syndrome.
Breastfeeding: Topical use is generally considered acceptable during breastfeeding, but caution is advisable if there is a family history of blood dyscrasias. Monitor the infant for gastrointestinal disturbances, adequate breastfeeding, and, if deemed necessary, complete blood count.
Drug Profile Summary
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Mechanism of Action: Chloramphenicol inhibits bacterial protein synthesis, while sulphacetamide interferes with bacterial folic acid synthesis.
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Side Effects: Common: Transient burning, stinging, blurred vision, eye irritation. Serious: Bone marrow suppression, aplastic anemia (systemic use), Gray baby syndrome (neonates with systemic use), Stevens-Johnson syndrome, Toxic epidermal necrolysis.
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Contraindications: Hypersensitivity to components, history of blood dyscrasias.
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Drug Interactions: Other topical ophthalmic medications, systemic antibiotics.
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Pregnancy & Breastfeeding: Topical use generally considered safe; systemic chloramphenicol should be avoided.
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Dosage: Adults and children ≥2 months: 1-2 drops/ 1/2 inch ribbon of ointment every 2-3 hours initially, then every 3-4 hours.
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Monitoring Parameters: Monitor for signs of infection resolution, ocular irritation, and any systemic side effects, especially in prolonged use.
Popular Combinations
Chloramphenicol + Sulphacetamide is itself a combination product. It’s not commonly combined with other medications in a single formulation.
Precautions
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General Precautions: Pre-screening for allergies and prior hypersensitivity reactions is necessary. Assess renal and hepatic function, particularly in patients with pre-existing conditions.
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Specific Populations: Exercise caution in pregnant and breastfeeding women. Use in neonates and infants requires careful consideration of potential systemic absorption and monitoring for adverse events. Geriatric patients may require dosage adjustments based on organ function.
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Lifestyle Considerations: Contact lenses should be avoided during treatment.
FAQs (Frequently Asked Questions)
Q1: What is the recommended dosage for Chloramphenicol + Sulphacetamide?
A: For adults and children ≥2 months, the typical dosage is 1-2 drops of solution or a small amount (1/2 inch ribbon) of ointment applied to the affected eye every 2-3 hours initially, and every 3-4 hours thereafter. Ointment application at bedtime is also recommended.
Q2: What are the most common side effects?
A: Burning or stinging upon instillation, temporary blurred vision, and mild eye irritation or redness are common side effects.
Q3: Can Chloramphenicol + Sulphacetamide be used during pregnancy?
A: Topical ocular administration is generally considered safe during pregnancy. Systemic chloramphenicol should be avoided, especially near term.
Q4: Is it safe to breastfeed while using this medication?
A: Topical use is generally acceptable during breastfeeding, but caution is warranted if a family history of blood dyscrasias exists. Closely monitor the infant for any unusual symptoms.
Q5: How long does treatment typically last?
A: Treatment duration is typically 5-7 days for uncomplicated infections, but it may extend to 10 days in more severe cases. Always follow the prescribed duration even if symptoms improve earlier.
A: Contact lenses should not be worn during treatment with Chloramphenicol + Sulphacetamide.
Q7: What should I do if my symptoms worsen or don’t improve?
A: Consult a healthcare professional if symptoms worsen, do not improve after several days of treatment, or if new symptoms develop.
Q8: Are there any serious side effects I should be aware of?
A: While rare with topical use, serious side effects can include bone marrow suppression, aplastic anemia, and severe allergic reactions. Immediately report any signs of these reactions to a healthcare professional.
Q9: How should Chloramphenicol + Sulphacetamide be stored?
A: Store as directed on the product packaging. Typically, it should be stored at room temperature and protected from light. Discard any remaining medication after the treatment course is completed.
