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. |
| Molecular Weight | 389.4 |
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 | Risk of teratogenicity; avoid use unless maternal benefit outweighs risk. |
| 2nd trimester | Fetal harm possible; limited data. |
| 3rd trimester | Avoid near term due to neonatal myelosuppression. |
Clinical note
Comprehensive clinical and safety monograph for MUTAMYCIN (MUTAMYCIN).
| Placental transfer | Crosses placenta; documented fetotoxicity and teratogenicity in animals. |
| Breastfeeding | Excreted in breast milk; potential for severe adverse reactions in nursing infants. Discontinue breastfeeding during therapy and for at least 7 days after last dose. |
| Lactation Rating | L5 (Contraindicated) |
■ 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 |
Hypersensitivity to mitomycinThrombocytopeniaCoagulation disordersActive bleeding
| Precautions | Myelosuppression, hemolytic uremic syndrome, renal toxicity, pulmonary toxicity (interstitial pneumonitis), extravasation risk (severe tissue necrosis), secondary malignancies (leukemia). |
| Food/Dietary | No specific food interactions are known. However, patients should maintain adequate hydration and nutrition. Avoid grapefruit juice if also receiving other interacting drugs. There is no restriction on eating grapefruit or other fruits. |
Loading safety data…
| 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 | 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. |
| Clinical Pearls | Mutamycin (mitomycin) is an alkylating agent used in combination chemotherapy for upper GI and anal cancers. It requires dilution and is given IV; avoid extravasation as it is a vesicant. Do not administer if absolute neutrophil count <1500/mm³ or platelets <100,000/mm³. Pulmonary toxicity (interstitial pneumonitis) is a rare but serious adverse effect; monitor for dyspnea, cough, and fever. Cumulative dose >60 mg/m² increases risk of hemolytic uremic syndrome (HUS). |
| Patient Advice | This medication can cause nausea, vomiting, and loss of appetite; antiemetics may be prescribed. · Report any signs of infection (fever, chills, sore throat) or unusual bleeding/bruising immediately. · Avoid sun exposure and use sunscreen; this drug may cause photosensitivity. · Do not receive live vaccines during treatment. · Use effective contraception during and for at least 6 months after treatment. · Notify your doctor if you experience shortness of breath, cough, or chest pain. |