Sulfachlor

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Sulfachlor

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Medically reviewed

Marina Burgos

Last updated on 10/01/2026

This page provides general, reference-level information compiled from official medical sources. It is not a substitute for professional medical advice, diagnosis, or treatment. For decisions about your health, please consult a qualified healthcare professional.

Overview of Sulfachlor

Quick Facts

Property Description
Active Ingredient(s) Chloramphenicol, Sulfacetamide
Form(s) Ophthalmic solution (Eye Drop), Ophthalmic ointment
Pharmacological Class Ophthalmic Anti-infective, Combination Antibiotic
Common Use Bacterial eye infections
Origin Synthetic

What Type of Ophthalmic Medicine is Sulfachlor?

Sulfachlor is a prescription-only combination antibiotic preparation classified as an ophthalmic anti-infective, designed specifically for topical application to the eye. This antibacterial agent is supplied in two principal dosage forms: a liquid ophthalmic solution (eye drop) or an ophthalmic ointment, ensuring the medicine is administered directly at the site of infection. As a combination product, its identity is defined by the inclusion of two distinct active pharmaceutical ingredients intended to act synergistically.

Composition: The Dual Action of Chloramphenicol and Sulfacetamide

The therapeutic foundation of Sulfachlor lies in the synergistic presence of its two active ingredients: Chloramphenicol and Sulfacetamide. Chloramphenicol is classified as an Amphenicol-class Antibacterial, while Sulfacetamide belongs to the Sulfonamide Antibacterial class. The strategic combination of these two agents from different pharmacological classes is clinically recognized for enhancing the spectrum of organisms targeted, a distinguishing feature compared to single-agent formulations. Both active ingredients are synthetic in origin and are combined into an appropriate base/vehicle (aqueous or oil) for effective topical delivery.

General Purpose and Benefit

The general purpose of Sulfachlor is to combat the microbial proliferation responsible for common bacterial eye infections, such as conjunctivitis and keratitis. By employing two different methods of cellular attack—inhibiting bacterial protein production and blocking the synthesis of essential bacterial metabolites—the preparation delivers a potent bacteriostatic effect. This dual-action strategy ensures that the pathogens causing the bacterial eye infections are prevented from multiplying, thereby clearing the condition and providing relief from the inflammation and discomfort caused by the uncontrolled growth of the microbes. Combination therapy containing Chloramphenicol has been extensively studied in treating bacterial eye diseases, supporting its use as a targeted anti-infective.

Regulatory References

  1. NIH Clinical Trials

What side effects are possible with Sulfachlor?

Possible Side Effects and Safety Information

The safety profile of this ophthalmic combination medicine is officially documented based on the characteristics of its active components, Chloramphenicol and Sulfacetamide. The information is derived from official government regulatory sources such as the FDA and EMA-aligned prescribing documents.

Localized and Frequency-Classified Reactions

The most frequently reported adverse reactions are localized effects pertaining to the Eye Disorders System-Organ Class. These commonly include transient local irritation, stinging, burning, and conjunctival hyperemia (redness) upon application. Less frequently, secondary infections or general hypersensitivity reactions (e.g., allergic reactions) may occur.

Documented Serious Systemic Risks

Official labeling documents that the medicine's active ingredients are associated with rare but serious systemic risks, although these are infrequently observed following topical ophthalmic use. The most critical safety characteristic is the potential for severe Blood and Lymphatic System Disorders. These include Aplastic Anemia (an irreversible, potentially fatal condition associated with Chloramphenicol) and other severe blood dyscrasias like Agranulocytosis (Sulfacetamide). Sulfonamides are also linked, rarely, to severe cutaneous reactions, such as Stevens-Johnson Syndrome (SJS) and Toxic Epidermal Necrolysis (TEN), and Fulminant Hepatic Necrosis.

Safety Patterns and Restrictions

Prolonged use of topical anti-bacterial agents may lead to the overgrowth of non-susceptible organisms, including fungi, and is also associated with the potential for Optic atrophy or Optic neuritis. Safety constraints specify that the medicine is contraindicated in individuals with a known personal or family history of blood dyscrasias, including aplastic anaemia. Furthermore, safety for use in pregnant or lactating women has not been established, and use in infants requires particular caution.

Overdose and Emergency Response

Overdose and When to Seek Help

Overdose information for this combination ophthalmic preparation is based on the documented systemic toxicities associated with its active components, Chloramphenicol and Sulfacetamide. Systemic overexposure, such as from accidental ingestion, may lead to severe or life-threatening manifestations, and official regulatory guidance mandates immediate emergency action.

Overdose Presentation and Risk Regulator-Mandated Action
Chloramphenicol Toxicity: Symptoms including abdominal distension, vomiting, irregular respiration, pallid cyanosis, and vasomotor collapse (Grey Syndrome) are documented systemic risks. Fatalities, and rare but severe blood disorders like aplastic anemia, have been reported. Seek immediate medical attention and contact a Poison Control Centre following accidental ingestion of any amount. Management is strictly symptomatic and supportive.
Sulfacetamide Toxicity: Overdosage carries the potential for signs such as nausea, vomiting, hematuria, and crystalluria, which involves the precipitation of sulfa crystals that can cause renal shutdown. Fatalities from severe hypersensitivity reactions (e.g., Stevens-Johnson syndrome) have rarely occurred. For severe systemic effects, urgent hospital treatment may be required. For local overexposure, immediately flush the affected eye(s) with water for at least 15 minutes, and seek an ophthalmological examination if symptoms persist.

Specific population risks are documented for neonates and infants, who are particularly susceptible to the severe, potentially fatal Grey Syndrome from Chloramphenicol systemic absorption. Due to the severe outcomes associated with the components, medical help must be sought immediately whenever an overdose or accidental over-application is suspected.

Therapeutic Uses of Sulfachlor

What Sulfachlor Treats: Main Uses and Benefits

The therapeutic use of Sulfachlor is based on its anti-infective properties. The medication is commonly used for managing acute bacterial infections of the eye, including common conditions like bacterial conjunctivitis and certain instances of keratitis. The primary benefit involves providing anti-infective support, which helps address the microbial cause of the condition.

The medication is relevant for easing symptoms that interfere with daily functioning. It helps address symptom clusters that may become intense or disruptive, such as pronounced eye redness, soreness, itching, and purulent discharge that may lead to crusted eyelids. This supportive relief assists with maintaining functional stability and helps patients cope more steadily with these difficult manifestations.

Additionally, the medication may be applied to assist with managing the risk of bacterial colonization following minor ocular injury or during post-surgical care.

Quick Fact: Symptom and Contextual Management
Symptom Clusters: Addresses symptoms related to inflammatory or irritative states, including redness, soreness, itching, and discharge.
Contextual Use: May be applied in clinical settings that involve acute or unstable symptom patterns, such as when short-term symptomatic assistance is needed.

Regulatory References

  1. National Institutes of Health (NIH) overview

Eligibility and Restrictions for Use

Who Can and Cannot Use Sulfachlor?

Eligibility for Sulfachlor (Chloramphenicol/Sulfacetamide ophthalmic) is strictly defined by regulatory documents, focusing on populations for whom use is contraindicated or restricted.


Absolute Contraindications

Use is absolutely prohibited for individuals with a documented hypersensitivity or allergy to Chloramphenicol, Sulfacetamide, or any antibiotic in the sulfa drug class. The medicine is also strictly contraindicated in patients with a personal or family history of blood dyscrasias, including aplastic anaemia, or previous myelosuppression from Chloramphenicol. Patients diagnosed with Acute Porphyria must also not use this medicine.


Restricted and Conditional Use

Use is highly restricted in certain age and physiological groups. It is contraindicated in neonates and preterm infants due to the risk of Gray Baby Syndrome. It is not recommended during the last month of pregnancy or while breastfeeding due to documented risks to the newborn. Children under 2 years of age require a specific medical prescription and oversight. Use in patients with known Hepatic or Renal impairment is conditional. Generally, the medicine is approved for use in adults and children aged 2 years and over provided no contraindications are present.

What should I know about interactions with other medicines?

Interaction scope

Medicinal product categories with documented interactions:

  • Drugs liable to depress bone marrow function (additive toxicity)
  • Anticoagulants (e.g., Dicumarol)
  • Anticonvulsants (e.g., Phenytoin)
  • Immunosuppressants (e.g., Cyclosporine)
  • Antidiabetic agents (Sulfonylureas)
  • Live-attenuated vaccines (Typhoid)
  • Silver preparations

Interaction-related restrictions: Co-administration with other medicines that depress bone marrow function must be avoided. Sulfacetamide preparations are officially incompatible with silver preparations.

Resulting interaction structure

Official interaction statements:

  • Metabolic Interaction: The Chloramphenicol component may inhibit the clearance of specific co-administered drugs, resulting in an officially documented increase in their plasma concentrations. This effect is relevant for agents such as Phenytoin, Dicumarol, Cyclosporine, and Sulfonylureas.
  • Pharmacodynamic Toxicity: An additive risk is documented if co-administered with other medicines that are liable to depress bone marrow function, warranting avoidance of this combination. The use of Chloramphenicol may also reduce the expected immunological response to the oral, live attenuated Typhoid vaccine.
  • Efficacy Reduction: The antibacterial action of the Sulfacetamide component is officially documented to be reduced by the presence of para-aminobenzoic acid (PABA).
  • Population-Specific Caution: A regulatory caution exists for use in neonates and infants, based on the risk of systemic accumulation of Chloramphenicol due to this population’s limited metabolic clearance capacity.

Connection to the overall interaction profile (2–4 sentences): The regulatory interaction profile for Sulfachlor is primarily defined by Pharmacokinetic Metabolic Clearance Inhibition and Additive Pharmacodynamic Toxicity related to the Chloramphenicol component. Further regulatory constraints include Substance Incompatibility of Sulfacetamide with silver preparations and an officially documented efficacy reduction from PABA.

Mechanism of Action

How Sulfachlor Works: Molecular Action and Bacteriostatic Effect

Sulfachlor achieves its effect through two distinct, complementary mechanisms that functionally arrest the growth and multiplication of susceptible bacteria at the site of administration. This combination strategy achieves a broad bacteriostatic effect through the simultaneous targeting of two essential bacterial life processes.

Dual Blockade of Bacterial Synthesis Pathways

The medicine targets two critical biosynthetic pathways required for bacterial viability. The Sulfacetamide component acts as a competitive inhibitor of the bacterial enzyme Dihydropteroate Synthase (DHPS). This action impedes the biosynthesis of essential folic acid by the pathogen, thereby depriving the cell of the necessary precursors for creating new DNA and RNA. Concurrently, the Chloramphenicol component binds to the bacterial 50S ribosomal subunit to inhibit peptidyl transferase, immediately arresting protein synthesis and the formation of essential enzymes and structural elements.

Resulting Bacteriostatic Cascade

The combined inhibition of both genetic material precursor synthesis and protein production arrests critical function in the bacterial cell. This dual blockade ensures a rapid and sustained cessation of bacterial growth and proliferation (bacteriostasis). The resulting physiological effect is the cessation of proliferation of the pathogen population, allowing the host's natural immune system to interact with the remaining, non-replicating microbes, leading to the resolution of infection-driven processes in the affected tissue.

Dosage and Administration Information

Instruction Map: How to use Sulfachlor

Administration Scope

Sulfachlor, a combination ophthalmic anti-infective, is strictly limited to topical administration to the eye, delivered as either an ophthalmic solution or an ophthalmic ointment. It is not approved for any other route, including injection.


Standardized Dosing and Frequency

The regimen involves instilling one to two drops of the ophthalmic solution or applying a small ribbon (approx 1/2 inch) of the ointment into the affected eye(s). Administration often requires a high initial frequency; the solution is typically applied every two to three hours during waking hours, or up to six times daily for severe cases. For the ointment, application is usually directed every three to four hours and at bedtime.


Course Duration and Adjustment

The total treatment course is short-term, typically lasting seven to ten days. A key element of the administration protocol is the tapering logic: the dosing frequency may be reduced (the time interval increased) as the condition shows clinical response. Treatment must be continued for the full prescribed duration or for an additional two days after visible symptoms have disappeared to comply with the established protocol.


Procedural and Population Rules

To comply with sterility requirements, the applicator tip of the container must not touch the eye, eyelid, or any other surface. Patients are instructed to remove contact lenses prior to administration and must not re-insert them throughout the treatment period. Use is established for pediatric patients two months of age and older, following the adult dosing regimens.

Recent Clinical Evidence

Sulfachlor: Recent Clinical Evidence

Evidence for Use in Acute Bacterial Eye Infections

Research has included extensive clinical studies and peer-reviewed systematic reviews to explore the use of this medicine in the context of common bacterial eye diseases, such as bacterial conjunctivitis and specific forms of keratitis. The active ingredients were observed in studies examining acute conditions characterized by fluctuating or episodic manifestations.

The research examined key outcomes related to microbial proliferation control (a physiological measurement) and monitored patient-reported outcomes describing changes in symptoms like eye redness, soreness, and discharge. The findings describe patterns observed in the studies regarding microbial clearance following administration, and this research examined study populations in clinical settings where conditions associated with acute or disruptive episodes were studied.

Evidence for Contextual Use

The medicine was evaluated in specific clinical situations relating to the potential reduction of bacterial colonization risk after minor ocular injury or during post-surgical care. Studies focusing on these scenarios reported findings describe patterns observed in the studies regarding the preparation’s use as a short-term intervention.

Research Gaps and Limitations

Certainty remains low regarding the full scope of outcomes. Long-term effects are not fully established as observation periods were limited to the acute phase. Data for certain groups remain insufficient, with subgroup findings uncertain for specific patient populations such as very young children or the frail elderly. Additionally, comparative evidence is lacking to fully detail its performance against all alternative single-agent ophthalmic antibiotics in high-level summaries.

Key Studies & References

  1. Topical antibiotics for acute bacterial conjunctivitis: a systematic review
  2. Chloramphenicol Resurrected: A Journey from Antibiotic Resistance in Eye Infections to Biofilm and Ocular Microbiota
  3. Sulfacetamide Sodium Ophthalmic Solution, USP - DailyMed (FDA Labeling)

Frequently Asked Questions (FAQ)

Common questions about Sulfachlor (FAQ)

Q: Can Sulfachlor be used for conditions not listed in the main uses?

Official regulatory documents specify the approved conditions for which Sulfachlor is indicated, primarily specific bacterial eye infections. The product has only been formally reviewed and approved by regulatory agencies for these labeled uses. This means that official product information does not cover use for any conditions that are not explicitly defined in the regulatory indication section.

Q: How quickly should I expect to see an effect from Sulfachlor?

Official prescribing information indicates that the dosage frequency may be reduced as the eye condition begins to show a clinical response. The medicine is designed to rapidly stop the growth of bacteria (a bacteriostatic effect) at the site of administration. However, official documents do not typically provide a specific timeline (e.g., hours or days) for when an individual patient should expect to notice symptom improvement.

Q: How long does Sulfachlor typically stay in your system?

Official documents address the pharmacokinetics of the active ingredients. For Chloramphenicol, one of the active ingredients, the half-life (the time it takes for half the drug to be cleared) is generally short in adults with normal organ function. This indicates that the drug is usually processed and cleared from the body relatively quickly after topical administration.

Q: What happens if I miss a scheduled time for Sulfachlor?

Official patient guidance for ophthalmic preparations often addresses the handling of a missed scheduled time. General regulatory-aligned advice often describes using the dose as soon as it is remembered. If it is near the time for the next scheduled dose, regulatory guidance suggests skipping the missed one to avoid administering an excessive amount of medicine. It is typically advised not to double up a dose to make up for a missed one.

Q: Does Sulfachlor cause stomach issues or nausea?

The most frequently reported side effects for topical Sulfachlor are generally localized to the eye, such as temporary stinging, burning, or irritation. While some systemic absorption is possible, official lists of common side effects do not usually include gastrointestinal issues or nausea. These types of side effects are more commonly associated with the systemic (non-topical) forms of Chloramphenicol mentioned in some regulatory documents.

Q: Can Sulfachlor cause skin rashes or sensitivity to the sun?

Sulfachlor contains Sulfacetamide, which is part of the Sulfonamide class of medicines. This class is officially associated with the potential for severe skin reactions and general hypersensitivity. This is a rare, but serious, documented risk, and patients are advised to review the official safety warnings regarding skin issues.

Q: Is it common to feel tired while taking Sulfachlor?

Fatigue or unusual weakness is not listed as a common side effect of topical Sulfachlor. However, regulatory safety documents indicate that these symptoms can be associated with the rare but serious blood disorders (like aplastic anemia) linked to the Chloramphenicol component.

Q: Does Sulfachlor interact with common pain relievers like ibuprofen?

Official interaction statements identify specific drug classes that may pose a risk due to metabolic changes or additive toxicity, such as blood thinners. Non-listed common pain relievers are generally not listed as an official contraindication in these documents. Official guidance emphasizes the importance of providing a complete list of all medicines, including OTC pain relievers, when reviewing a treatment plan.

Q: Are there any known food or drink interactions with Sulfachlor?

Official interaction statements document that the antibacterial action of the Sulfacetamide component can be reduced by the presence of para-aminobenzoic acid (PABA). PABA is a substance that may be found in some cosmetics, sunscreens, and other topical products. There are generally no food or drink interactions specified in the official documents.

Q: Can I drink alcohol while using Sulfachlor?

Official patient information typically includes a specific statement regarding the use of alcohol. For the ophthalmic form of Sulfachlor, no interaction that reduces the effectiveness of the drug has been widely established in regulatory documents. The medicine's specific guidance should be reviewed for use with alcohol.

Q: What are the warnings about Sulfachlor and kidney problems?

Official prescribing documents state that the use of Sulfachlor is conditional in patients with known renal (kidney) impairment. This precaution exists due to the potential for the Chloramphenicol component to accumulate in the body when the ability to clear the medicine is limited.

Q: Can Sulfachlor affect blood thinners like warfarin?

Official interaction statements document that the Chloramphenicol component may inhibit the clearance of co-administered drugs, which could lead to an increase in their concentration in the body. This is a documented concern for blood thinning agents (anticoagulants), specifically referencing Dicumarol and other agents in that class.

Q: Why do I need a prescription for Sulfachlor?

Sulfachlor is classified by regulatory bodies as a Prescription Only Medicine (POM). This status ensures that the medicine is used under the supervision of a healthcare professional. This level of oversight is required due to the drug’s potential side effects, the need for accurate diagnosis of bacterial infection, and the importance of managing antimicrobial resistance.

Q: Are there specific tests I need before starting Sulfachlor?

Regulatory information indicates that for the systemic forms of the active ingredients, periodic laboratory testing may be required to monitor for side effects. However, for topical ophthalmic use, such monitoring tests are generally not required unless a patient has a pre-existing history of blood dyscrasias.

Q: Is Sulfachlor considered a 'strong' medicine?

Official documents describe the medicine's effect as a dual blockade because it targets two essential bacterial life processes simultaneously: inhibiting folic acid synthesis and arresting protein synthesis. This combination is described as achieving a potent bacteriostatic effect, meaning it stops the growth and multiplication of the bacteria.

Q: How effective is Sulfachlor compared to what the official documents say?

Research evidence supporting the medicine includes clinical studies that have examined key outcomes such as controlling microbial proliferation and measuring changes in patient-reported symptoms. The findings of these studies describe patterns observed regarding microbial clearance and changes in inflammation, soreness, and discharge in study populations.

Q: What is the risk of resistance developing with Sulfachlor?

Official regulatory warnings state that prolonged use of any topical anti-bacterial agent, including Sulfachlor, may lead to the overgrowth of non-susceptible organisms, such as fungi. This is a general caution associated with the use of antimicrobial medicines.

Q: Is it normal to feel a bit dizzy when first starting Sulfachlor?

The most common side effects of this ophthalmic medicine are temporary and localized to the eye. One such common effect is temporary blurring of vision immediately after administration. This visual change, while brief, may cause a feeling of unsteadiness, which can be perceived as dizziness.

Q: What is the function of the inactive ingredients in Sulfachlor?

Official product information for Sulfachlor lists both the active ingredients and the inactive ingredients (excipients). These inactive ingredients do not provide the therapeutic effect but are necessary for the medicine to function. Their purpose includes maintaining the product's stability, ensuring sterility, and giving the product its correct physical form (solution or ointment base).

Q: Does Sulfachlor contain gluten or common allergens?

The medicine is strictly contraindicated for anyone with a known allergy to its active ingredients (Chloramphenicol and Sulfacetamide) or any drug in the sulfa class. The official list of inactive ingredients (excipients) is published in regulatory documents, and the presence or absence of common allergens like gluten is based on that specific list.

Q: What is the difference in how Sulfachlor works compared to penicillin?

Official documents detail Sulfachlor’s mechanism as a dual-action agent that achieves its effect by inhibiting the synthesis of folic acid and simultaneously arresting protein synthesis in the bacterial cell. Regulatory documents focus solely on describing the specific way this medicine works.

Q: Can Sulfachlor affect your ability to drive or operate machinery?

As an ophthalmic medicine, a common side effect is the temporary blurring of vision immediately following application. Official patient information indicates that it is important to wait until vision clears before operating machinery or driving.

Q: Is Sulfachlor considered a 'scheduled' or controlled drug?

Sulfachlor is generally classified by regulatory bodies as a Prescription Only Medicine (POM), meaning it is not available over the counter. However, it is not typically classified as a scheduled or controlled drug, as those designations are usually reserved for medicines that have a recognized potential for misuse or addiction.

Q: Where can I find the official patient information leaflet for Sulfachlor?

The official Patient Information Leaflet (PIL) or its equivalent, the Summary of Product Characteristics (SmPC), is made publicly available by regulatory authorities. These documents can typically be found by searching government-run databases such as the FDA’s DailyMed or the UK’s GOV.UK website.

How should Sulfachlor be stored and disposed of?

Official Storage and Disposal Requirements

Official regulatory labeling for Sulfachlor specifies precise conditions necessary for maintaining the product's stability and sterility.

Storage Condition
Temperature: Store within the mandated range, generally between 2 C to 25 C (36 F to 77 F), and protect from freezing.
Protection: Keep the medicine out of the reach of children and store it protected from light.
Container: The container must be kept tightly closed to prevent contamination. Avoid touching the container tip to the eye or any surface.

Stability and Disposal: The product is typically limited to an in-use period (e.g., 30 days) once opened and must be discarded immediately if the solution changes color. Unused or expired Sulfachlor must be managed as pharmaceutical waste; do not dispose of it in household trash or down the drain, and consult a pharmacist for official disposal guidance.

Attention! Always consult to a doctor or pharmacist before using pills or medicines.

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