Mitomycin is a potent antineoplastic antibiotic derived from *Streptomyces caespitosus*. It functions as a bioreductive alkylating agent, requiring intracellular enzymatic activation to form DNA cross-links, leading to inhibition of DNA synthesis and cell death. It is a key component in the treatment of various solid tumors, particularly in the Indian context for cancers like anal, bladder, and gastric cancers, where it is often used in combination regimens or as an intravesical agent.
Adult: **IV:** Varies by protocol. Common regimens: 10-20 mg/m² as a single dose every 6-8 weeks, OR 2 mg/m²/day for 5 days every 6 weeks. **Intravesical:** 20-40 mg in 20-40 mL of sterile water instilled into the bladder once weekly for 8 weeks, then monthly for up to 1 year. Dose must be individualized based on BSA, hematological parameters, and regimen.
Note: **IV Use:** Reconstitute 10mg vial with 10-40mL of Sterile Water for Injection. Administer as a slow IV push or short infusion (over 5-20 minutes). **MUST** be given through a free-flowing IV line to avoid extravasation. **Intravesical Use:** Instill via urethral catheter into empty bladder, retain for 1-2 hours. Patient should rotate position every 15 minutes. Avoid concurrent systemic absorption by ensuring no urinary tract trauma.
Mitomycin is a prodrug that undergoes enzymatic bioreduction (primarily in hypoxic tumor cells) to generate reactive intermediates. These intermediates alkylate DNA, forming covalent cross-links primarily between the N2 position of guanine residues on complementary DNA strands. This cross-linking inhibits DNA synthesis and transcription, leading to single-strand breaks and ultimately, cell cycle arrest and apoptosis.
Pregnancy: **FDA Pregnancy Category D.** Can cause fetal harm. Avoid in pregnancy, especially first trimester. If used, patient must be informed of potential risk. Effective contraception required.
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) | Risk of disseminated infection due to immunosuppression. Contraindicated. | Major |
| Cimetidine | May inhibit hepatic microsomal enzymes, potentially increasing Mitomycin toxicity. Monitor closely. | 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). Additive myelosuppression. | Major |