MUTAMYCIN
Clinical safety rating: caution
Comprehensive clinical and safety monograph for MUTAMYCIN (MUTAMYCIN).
Cross-links DNA strands, inhibiting DNA synthesis and function.
| Metabolism | Hepatic via CYP450 enzymes, primarily CYP2C9 and CYP3A4. |
| Excretion | Primarily hepatic metabolism; approximately 10-30% excreted unchanged in urine; small amount in bile. |
| Half-life | Terminal half-life: 30-60 minutes; clinically, rapid clearance necessitates IV bolus administration. |
| Protein binding | Approximately 80-90% bound to plasma proteins, weakly bound. |
| Volume of Distribution | Approximately 0.3-0.6 L/kg; suggests distribution extracellularly with limited tissue penetration except in bladder. |
| Bioavailability | IV: 100%; intravesical: minimal systemic absorption (<1%). |
| Onset of Action | IV: 1-2 weeks (delayed myelosuppression); intravesical: 1-2 hours. |
| Duration of Action | Myelosuppression lasts 3-4 weeks; intravesical effects last 24-48 hours. |
20 mg/m² intravenously every 6 to 8 weeks, as a single bolus dose.
| Dosage form | INJECTABLE |
| Renal impairment | No specific dose adjustment recommended; use with caution in renal impairment. |
| Liver impairment | No specific dose adjustment recommended; use with caution in hepatic impairment. |
| Pediatric use | Safety and efficacy not established; no standard pediatric dosing available. |
| Geriatric use | No specific dose adjustment recommended; monitor for increased toxicity due to potential age-related organ dysfunction. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for MUTAMYCIN (MUTAMYCIN).
| Breastfeeding | Contraindicated during breastfeeding. Mitomycin is excreted in human milk; M/P ratio not determined. Potential for severe adverse reactions in nursing infants (bone marrow suppression, carcinogenesis). |
| Teratogenic Risk | FDA Pregnancy Category D. First trimester: high risk of malformations (neural tube, skeletal, visceral). Second/third trimester: increased risk of intrauterine growth restriction (IUGR), oligohydramnios, premature labor, and fetal death due to mutagenic and cytotoxic effects. |
| Fetal Monitoring |
■ FDA Black Box Warning
Bone marrow suppression (myelosuppression) is common, severe, and potentially fatal. Hemolytic uremic syndrome (HUS) with microangiopathic hemolytic anemia, thrombocytopenia, and renal failure may occur. Use with caution in patients with renal impairment.
| Serious Effects |
Absolute: Hypersensitivity to mitomycin, thrombocytopenia or coagulation disorders (risk of bleeding). Relative: Renal impairment (CrCl < 30 mL/min), active infection, hepatic impairment.
| Precautions | Myelosuppression, hemolytic uremic syndrome, renal toxicity, pulmonary toxicity (interstitial pneumonitis), extravasation risk (severe tissue necrosis), secondary malignancies (leukemia). |
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| Monitor complete blood count (CBC) with differential weekly; renal function (serum creatinine, BUN) and hepatic function (AST, ALT, bilirubin) every cycle; fetal ultrasound for growth and amniotic fluid volume every 4 weeks; assess for signs of hemolytic uremic syndrome (HUS) and pulmonary edema. |
| Fertility Effects | Gonadal toxicity common: amenorrhea, oligospermia, azoospermia; risk of permanent infertility, especially in prepubertal patients; consider fertility preservation consultation prior to treatment. |