Mitomycin is a potent antineoplastic antibiotic derived from *Streptomyces caespitosus*. It functions as a bioreductive alkylating agent, requiring intracellular enzymatic activation to form cross-links in DNA, leading to inhibition of DNA synthesis and cell death. It is a key component in the management of various solid tumors and is uniquely used in ophthalmology for glaucoma surgery.
Adult: **IV:** 10-20 mg/m² as a single dose every 6-8 weeks. Commonly 10 mg/m². Dose is part of a combination regimen. **Intravesical:** 20-40 mg in 20-40 mL sterile water instilled into the bladder weekly for 8 weeks, then monthly for up to 1 year. **Ophthalmic (Surgery):** 0.2-0.4 mg/mL solution applied via soaked sponge for 2-5 minutes, followed by copious irrigation.
Note: **IV Route:** Reconstitute with Sterile Water for Injection. Administer as a slow IV push or short infusion (5-10 minutes) through a **freely flowing IV line**. **EXTRAVASATION HAZARD:** Must be administered by personnel trained in handling vesicants. **Intravesical:** Patient should restrict fluids prior, instil drug, retain for 1-2 hours, reposition every 15 minutes, then void.
Mitomycin is a prodrug that requires enzymatic bioreduction (via NADPH-cytochrome c reductase, DT-diaphorase) in hypoxic tumor cells to generate reactive intermediates. These intermediates act as bifunctional or trifunctional alkylating agents, forming covalent cross-links primarily between the N-2 positions of adjacent guanine residues on complementary strands of DNA. This inhibits DNA synthesis and transcription, leading to single-strand breaks and cell cycle arrest, predominantly in the late G1 and S phases.
Pregnancy: **FDA Pregnancy Category D.** There is positive evidence of human fetal risk based on adverse reaction data from investigational or marketing experience. Mitomycin is teratogenic and embryotoxic. Contraindicated in pregnancy. Effective contraception required during and for at least 6 months after therapy.
Driving: May cause fatigue, malaise, or dizziness. Patients should be cautioned about operating machinery or driving if affected.
| Other Myelosuppressive Agents (e.g., Doxorubicin, Cyclophosphamide) | Additive bone marrow toxicity. Increased risk of severe leukopenia/thrombocytopenia. | Major |
| Live Vaccines (e.g., MMR, Varicella, Yellow Fever) | Risk of disseminated infection due to immunosuppression. Vaccination contraindicated. | Major |
| Cimetidine | May inhibit hepatic microsomal enzymes, potentially increasing Mitomycin toxicity. | Moderate |
| Vitamin K Antagonists (Warfarin) | Increased risk of bleeding due to thrombocytopenia and possible interference with coagulation. | Moderate |
| Radiotherapy | Enhanced toxicity in irradiated fields (recall phenomenon). Increased risk of pulmonary toxicity. | Major |