Mitomycin (Topical)

Overview

Mitomycin boosts success rates for eye-related procedures by inhibiting specific DNA reactions responsible for wound healing. Derived from the bacterium Streptomyces casepitosus, its antimetabolite qualities prevents recurrence rates for pterygium surgery, reduces the formation of scar tissue from glaucoma filtration surgery and reduces the likelihood of visual haze from Photorefractive keratectomy, or Lasik, surgery.

In addition to its ability to increase desirable post-surgery results, Mitomycin can also be used as an effective treatment for allergic conjunctivitis. This inflammatory condition commonly results in redness, liquid discharge, photophobia and sensations of foreign objects in the eyes.

Topical application of Mitomycin has shown to reduce, but not eliminate, these symptoms. Due to the complex nature of this medication, application for non-surgical treatments must be performed in a clinical setting.

Ultimately, Mitomycin supports surgical and non-invasive procedures used to restore and safeguard eyesight.

According to clinical studies reported in a variety of medical journals, topical application of Mitomycin reduced IOP, or intraocular pressure, by 3 mmHg when used in glaucoma filtration surgery. These findings are impressive, however, the reduction of intraocular pressure is greater in studies with historical control. In these studies, patients experienced a 5 mmHg reduction after 12 months.

While Mitomycin is an effective medication to prevent complications from ocular surgeries, its exact absorption pharmacokinetics is unknown to clinicians. When applied to treatment areas, the active compounds are cleared past ophthalmic tissue. Once absorbed into the body, systemic clearing is performed by the liver. However, the rate of clearance varies based on liver metabolism and pathway degradation.

Conditions Treated

  • Glaucoma filtering surgery
  • Refractive surgery
  • Pterygium surgery
  • Ocular surface tumors
  • Allergic conjunctivitis
  • Dacryocystorhinostomy (DCR)
  • Squint surgeries
  • Photorefractive keratectomy
  • Esophageal/Tracheal stenosis application

Type Of Medicine

  • Antimetabolites

Side Effects

While Mitomycin successfully produces desirable effects in the majority of patients, this powerful topical drug may also cause a variety of unsavory side effects. The most common negative side effects include redness in or around the treated eye and eye pain. Due to its complex biological activity, Mitomycin side effects also include blurred vision, change in vision clarity or perception, as well as generalized eye irritation and/or inflammation.

Visual disturbances aren't uncommon following any eye-related procedure. Mitomycin may exasperate such effects. The most common includes random flashes of light or sparks within your field of vision. Other visual abnormalities include blocked vision, which looks like a veil or curtain is blocking a portion of your field of vision. Floating spots, or squiggly lines, have also been reported after Mitomycin application.

It's important to note that some side effects related to Mitomycin aren't serious, and don't require assistance by your doctor. These typically include headache, excessive eye watering and non-obstructive inflammation. However, there are more serious side effects that should immediately be discussed and evaluated by a physician.

The more common serious side effects include reopening of the surgical wound, which can result in potentially permanent damage. While light sensitivity isn't uncommon following invasive eye procedures, if light sensitivity becomes severe, you should immediately discuss this side effect with your doctor. Other serious side effects include throbbing pain in or around your eyes as well as an uncontrolled raising of your upper eyelid.

The rarest of side effects are also the most detrimental. Mitomycin is reported to produce such severe effects, such as blindness or severe vision loss. Following application, it's possible to experience obstruction in your lacrimal drainage system or sclera ulceration.

Because eye-related disturbances can be difficult to navigate, it's imperative to remain vigilant during the healing phase. While side effects may not be caused by Mitomycin, but rather from the actual procedure, any symptom that's uncomfortable or worrisome must be discussed with your physician. Failure to do so can cause permanent vision loss or result in severe complications.

Dosage

Due to the severe nature of Mitomycin, administration and dosing is done by a licensed physician. This topical medication requires precise mixing and application, which makes it inappropriate for patient-directed application.

Mitomycin is intended specifically for surgical site application, and is not designed for intraocular use. To ensure proper dosage, Mitomycin comes in a complete kit. This kit includes everything needed to safeguard preparation, dosage limits and application.

The pre-measured vials contain 0.2 mg of Mitomycin and Mannitol. The concentration of these two compounds is at a 1:2 ratio. Before application, the medication must be reconstituted. To accomplish this, 1mL of Sterile Water is injected into the vial. The practitioner then shakes the vial to dissolve the ingredients. This process can take several minutes.

Once the solution is fully dissolved, specialized sponges are saturated based upon instructions provided by the manufacturer. The soaked sponge is then applied directly to the treatment area for two minutes. Sponges are secured by surgical forceps and then removed after 120 seconds.

Interactions

There aren't any known drug interactions when Mitomycin is appropriately applied. This being noted, it's important to avoid eye drops or any other medicine delivered directly to the eyes without consent from your physician.

Warnings

The most notable warning when taking Mitomycin is its application site. Because this medication is a cytotoxic agent, it's imperative that its application is reserved only for the topical use of surgical sites.

As mentioned earlier, if Mitomycin is used intraocularly, severe reactions occur. This includes cellular death, which can lead to retinal and corneal infarction. Other severe reactions when used in this manner include ciliary body atrophy and complete blindness.

The potency of Mitomycin requires precise application time limits. Failure to adhere to the two-minute application duration can result in serious side effects. Perhaps the most severe side effects is thinning or perforation of the cornea. Should the solution accidentally come in contact with certain eye components, such as the corneal endothelium, the cytotoxic nature of Mitomycin will cause permanent cell death.

While Mitomycin is generally considered safe when used according to the established best practices, there is substantial evidence this medicine can be detrimental during pregnancy.

Officially categorized as 'œX,' use of Mitomycin while pregnant is not recommended as the potential benefits do not outweigh the risk of adverse reactions. Although it's not established whether or not the medicine can be passed through breast milk, breastfeeding mothers should discuss the possibility or risk with their physician.

While still debated, studies have shown Mitomycin may be dangerous when taken while pregnant, or when conception occurs during treatment. The most notable risk is serious fetal harm. If a patient is attempting to become pregnant around treatment dates, Mitomycin therapy may not be recommended.

According to clinical trials, Mitomycin treatments have been connected with an increased risk and/or instance of post-surgery hypotony. This situation is when a cataract is removed. While rare, this situation results in a non-healing or continuously leaking wound. When this occurs, it's possible to experience internal fistulas.

When used in phakic patients, the use of Mitomycin has been attributed to an increased instance rate of cataract formation and lenticular alteration. Patients who have had a negative interaction with Mitomycin in the past shouldn't continue to use this medication.

Storage

Because Mitomycin will be administered in a clinical setting, storage is under the supervision of medical professionals. As a general rule, Mitomycin should be stored in a dry location with temperates no lower than 68 degrees Fahrenheit, and no higher than 77 degrees Fahrenheit.

Due to the serious nature of the medication, storage and handling procedures must align with the established guidelines for all anti-cancer drugs. Disposal of used kits and sponges must align with chemotherapy disposal guidelines.

Summary

Since its introduction as a ophthalmic agent in 1969, the use of Mitomycin has transformed the success and viability of ocular-related procedures. Much like any other medication within this class, its positive potential isn't without negative possibilities.

Whether used to prevent scar tissue formation from glaucoma filtration surgeries, or to reduce the symptoms of allergic conjunctivitis, Mitomycin is a powerful tool in the arsenal of vision restoration.

Prior to administering this medication, it's important to communicate several key points. The most important of these is to discuss pregnancy. If a patient is currently pregnant, or may become pregnant during the treatment, the use of Mitomycin isn't recommended. The same is true if a patient is breastfeeding.

Although the risk of serious side effects is very real, so is the potential of Mitomycin. Whenever issues arise within the eyes, extreme care must be taken in both the procedure and administration of medications. While Mitomycin has the potential to directly cause complications, with proper administration, it's possible to avoid exasperating an already serious situation.

In summary, Mitomycin offers a myriad of benefits designed to protect vision by inhibiting unsavory surgical side effects. With proper administration, and appropriate post-surgical care, this medication is powerful option for eye-related procedures.