mitomycin (ophthalmic)

Action and Spectrum

Actions and Spectrum: 

mitomycin (ophthalmic) is an ophthalmic medication used in eye surgeries, primarily for treating certain eye conditions. It is commonly used to prevent excessive scarring and fibrosis after glaucoma and pterygium excision surgery.  

Action:  

mitomycin belongs to a class of drugs known as antineoplastic antibiotics. It exerts its effects by inhibiting the synthesis of DNA (deoxyribonucleic acid) in healthy and abnormal cells. DNA is essential for cell division and replication, and by interfering with its synthesis, mitomycin can impede the proliferation of cells. This property is particularly beneficial in eye surgeries to avert the formation of excessive scar tissue. 

Spectrum of Use: 

• Glaucoma Surgery: mitomycin is commonly used in glaucoma surgery, particularly in trabeculectomy. Trabeculectomy is a surgical procedure that creates a new drainage channel in the eye to reduce intraocular pressure. The application of mitomycin during this surgery helps prevent scar tissue formation around the drainage site, which could otherwise block the outflow of aqueous humor and reduce the effectiveness of the surgery. 
• Pterygium Excision Surgery: A pterygium is a growth of conjunctival tissue that generally extends onto the cornea, potentially affecting vision and causing discomfort. In pterygium excision surgery, the pterygium is removed, and mitomycin is applied to the affected area to inhibit the regrowth of the abnormal tissue and minimize the chances of recurrence. 

Drug Interaction

Adverse Reaction

Frequency not defined 

Wound dehiscence 

Endophthalmitis 

Inflammation 

Blebitis 

Hyphema 

retinal hemorrhage 

choroidal detachment 

Black Box Warning

Black Box Warning: 

None 

Contraindication / Caution

Contraindication/Caution: 

Contraindication 

• Hypersensitivity or Allergy: Individuals with known hypersensitivity or allergy to mitomycin or its components should not use this medication. Allergic reactions can vary from mild skin irritations to severe systemic reactions, and in such cases, alternative treatments should be considered. 
• Pregnancy and Breastfeeding: mitomycin’s safety during pregnancy and breastfeeding has not been established. Due to its potential teratogenic (harmful to the fetus) and toxic effects, it should be avoided in pregnant and breastfeeding individuals unless the potential benefits outweigh the risks. Pregnant or breastfeeding individuals should discuss the risks and benefits with their healthcare provider before using mitomycin. 
• Active Eye Infections: mitomycin should not be used in patients with active eye infections. Applying mitomycin to an infected eye can worsen the infection and lead to severe complications. 
• Severe Dry Eye: Individuals with severe dry eye or ocular surface disease may be at increased risk of experiencing adverse effects when using mitomycin. The medication’s use in such cases should be carefully evaluated and monitored by an ophthalmologist. 
• Corneal Epithelial Defects: mitomycin should be used cautiously in patients with corneal epithelial defects, as it may slow the healing process and lead to complications. 
• Uncontrolled Glaucoma: Patients with uncontrolled glaucoma may be at risk of further complications when using mitomycin during glaucoma surgery. The medication’s use should be carefully considered, and alternative treatments may be considered. 
• Children: mitomycin is not typically recommended for children due to this population’s lack of sufficient safety and efficacy data. 

Caution 

• Proper Administration: mitomycin should only be administered by trained ophthalmic surgeons experienced in using the medication during eye surgeries. The correct dosage and application technique should be followed to ensure optimal results and minimize the risk of complications. 
• Dosing: mitomycin is a powerful medication, and its concentration and exposure time should be considered to avoid excessive effects on the eye tissues. Overexposure or incorrect dosing can lead to complications such as delayed wound healing, corneal thinning, and other serious adverse effects. 
• Eye Surface Health: The ophthalmologist should carefully assess the health of the eye surface and cornea before using mitomycin. Patients with pre-existing ocular surface disease or corneal epithelial defects may be at increased risk of complications when using this medication. 
• Wound Leakage: mitomycin should not be used if there is a significant risk of wound leakage after surgery. The medication can leak into the anterior chamber and cause adverse effects on intraocular structures. 
• Infections: The risk of infection may increase with the use of mitomycin. Proper aseptic techniques should be followed during surgery to minimize the risk of post-operative infections. 
• Intraocular Pressure: mitomycin can reduce intraocular pressure (IOP) after surgery. Ophthalmologists should monitor IOP closely during the post-operative period to ensure it does not drop to dangerously low levels. 
• Healing Delay: mitomycin can delay the healing process of the surgical site. Ophthalmologists should carefully assess the benefits and risks of using mitomycin in each case, especially in patients with a history of slow wound healing. 
• Systemic Effects: While mitomycin (ophthalmic) is mainly applied locally during eye surgery, there is a potential for systemic absorption, especially if it leaks into the bloodstream. Patients with a history of significant systemic reactions to mitomycin or other medications should be closely monitored. 
• Pregnancy and Breastfeeding: As mentioned earlier, mitomycin’s safety during pregnancy condition and breastfeeding has not been established. It should be avoided in pregnant and breastfeeding individuals unless the potential benefits outweigh the risks. 
• Children: The safety and efficacy of mitomycin (ophthalmic) in children have not been extensively studied. Its use in pediatric patients should be carefully considered, and alternative treatments may sometimes be preferred. 

Pregnancy / Lactation

Pregnancy consideration:  

US FDA pregnancy category: Not assigned 

Lactation:   

Excreted into human milk: Not known. 

Pregnancy category: 

• Category A: well-controlled and Satisfactory studies show no risk to the fetus in the first or later trimester. 
• Category B: there was no evidence of risk to the fetus in animal studies, and there were not enough studies on pregnant women. 
• Category C: there was evidence of risk of adverse effects in animal reproduction studies, and no adequate evidence in human studies must take care of potential risks in pregnant women.    
• Category D: adequate data with sufficient evidence of human fetal risk from various platforms, but despite the potential risk, and used only in emergency cases for potential benefits.    
• Category X: Drugs listed in this category outweigh the risks over benefits. Hence these categories of drugs need to be avoided by pregnant women.    
• Category N: There is no data available for the drug under this category. 

Pharmacology

Pharmacology: 

mitomycin (ophthalmic) is an antineoplastic antibiotic with potent pharmacological properties used in ophthalmic surgery. Its action mechanism involves inhibiting DNA synthesis by cross-linking strands, both in healthy and abnormal cells. This interference disrupts the replication and division of cells, mainly fibroblasts responsible for collagen formation.

In ophthalmic surgery, mitomycin is employed to prevent excessive scarring and fibrosis that can occur after procedures like trabeculectomy for glaucoma or pterygium excision surgery. Applying mitomycin topically to the surgical site reduces fibroblast proliferation and inhibits scar tissue formation. 

Pharmacodynamics: 

Mechanism of action: The mechanism of action of mitomycin (ophthalmic) involves its role as an antineoplastic antibiotic that inhibits the synthesis of DNA in both healthy and abnormal cells. In the context of ophthalmic surgery, mitomycin prevents excessive scarring and fibrosis that can occur after specific eye procedures. 

• Inhibition of DNA Synthesis: mitomycin belongs to a class of drugs known as alkylating agents. When applied locally to the eye during surgery, mitomycin enters the cells and becomes activated. It forms covalent bonds with the DNA strands in the cell’s nucleus. 
• DNA Cross-Linking: Once bound to the DNA, mitomycin forms cross-links between the strands of the DNA double helix. These cross-links prevent the DNA from unwinding and inhibit its ability to replicate and divide during cell division. 
• Cell Cycle Arrest: By interfering with DNA replication and cell division, mitomycin induces cell cycle arrest. This means that cells cannot progress through their normal life cycle and cannot proliferate as they usually would. 
• Inhibition of Fibroblast Proliferation: Fibroblasts are cells responsible for producing collagen, which is the main component of scar tissue. During ophthalmic surgery, fibroblasts can become active and contribute to scar tissue formation at the surgical site. mitomycin’s inhibition of fibroblast proliferation helps to reduce the formation of excessive scar tissue, known as fibrosis. 
• Reduction of Scarring: By inhibiting the proliferation of fibroblasts and reducing the formation of scar tissue, mitomycin helps to prevent excessive scarring and fibrosis at the surgical site. This is particularly beneficial in procedures like trabeculectomy for glaucoma or pterygium excision surgery. 

Pharmacokinetics: 

Absorption 

mitomycin is intended to remain at the application site to exert its pharmacological effects locally when applied topically to the eye during surgery. The medication is not designed for significant systemic absorption. 

Distribution 

Due to its localized application, mitomycin remains primarily confined to the eye tissues at the surgical site. The medication’s distribution beyond the ocular tissues is minimal and does not reach high concentrations in other body tissues or organs. 

Metabolism 

mitomycin undergoes metabolic processes in the body, primarily in the liver, when administered systemically for cancer treatment. However, when used ophthalmically, there is limited systemic exposure; hence, the extent of metabolism is negligible. Most of the applied mitomycin likely remains unchanged at the site of administration. 

Elimination and Excretion 

The excretion of mitomycin following ophthalmic use is not a significant concern because it is not expected to be systemically absorbed in significant amounts. Any minimal systemic absorption that does occur is likely eliminated primarily through the kidneys and excreted in the urine. 

Adminstartion

Administration: 

Ophthalmic administration 

mitomycin (ophthalmic) is typically administered during certain eye surgeries to prevent excessive scarring and fibrosis. The administration of mitomycin must be performed by a qualified ophthalmologist with experience in using the medication.  

• Preparation: Before administering mitomycin, the ophthalmologist will ensure that the individual is a suitable candidate for the medication and that the surgery is indicated. The appropriate concentration and dosage of mitomycin will be determined based on the specific surgical procedure and the patient’s individual needs. 
• Surgical Procedure: mitomycin is commonly used during glaucoma surgery, particularly in trabeculectomy and pterygium excision surgery. The ophthalmologist will perform the surgical procedure as planned, and when the appropriate moment arises during the surgery, mitomycin will be applied. 
• Application: mitomycin is usually applied topically to the target area, which is the conjunctival or episcleral tissues in the case of glaucoma surgery or the excised area in pterygium excision surgery. The medication is often delivered in a solution or soaked onto a sterile or surgical cellulose sponge (e.g., Weck-Cel sponge) for precise application. 
• Exposure Time: The exposure time of mitomycin to the surgical site is critical. It is typically applied for a short duration (usually a few minutes) to minimize the risk of adverse effects and complications associated with prolonged exposure. 
• Rinsing: After the desired exposure time, the ophthalmologist will thoroughly rinse the surgical area with a balanced salt solution or another appropriate irrigating solution to remove any remaining mitomycin and prevent further contact with intraocular structures. 
• Post-operative Care: After administering mitomycin, the ophthalmologist will provide appropriate post-operative care instructions to the patient. This may include using prescribed eye drops, intraocular pressure monitoring, and regular follow-up visits to assess healing and manage potential complications. 

Patient Information Leaflet

Patient information leaflet 

Generic Name: mitomycin (ophthalmic) 

Why do we use mitomycin (ophthalmic)? 

mitomycin (ophthalmic) is primarily used in ophthalmic surgery to prevent excessive scarring and fibrosis after specific procedures. Its use is limited to the surgical setting and is not typically prescribed for regular eye conditions or as a standalone eye drop for treatment.  

• Glaucoma Surgery (Trabeculectomy): mitomycin is commonly used during trabeculectomy, a surgical procedure to treat glaucoma. In trabeculectomy, a new drainage channel is created in the eye to improve the outflow of aqueous humor and reduce intraocular pressure. mitomycin is applied to the surgical site to prevent excessive scarring around the drainage site, which could otherwise impede the flow of aqueous humor and decrease the effectiveness of the surgery. 
• Pterygium Excision Surgery: mitomycin is used in pterygium excision surgery, a procedure to remove a pterygium, a growth of conjunctival tissue extending onto the cornea. After removing the pterygium, mitomycin is applied to the affected area to inhibit the regrowth of the abnormal tissue and reduce the likelihood of pterygium recurrence.