mitomycin: clinical use

Prescribing considerations

• Restrict use to clinicians experienced in cytotoxic therapy and confirm that the product is suitable for the intended route.
• Before intravesical administration, exclude bladder perforation and assess active cystitis; use atraumatic, low-pressure catheterisation.
• Systemic toxicity may be delayed and cumulative, particularly myelosuppression. Consider previous cytotoxic treatment, radiotherapy, general condition and organ function.
• Treat new unexplained pulmonary symptoms, haemolysis or renal dysfunction as potential serious mitomycin toxicity.
• Mitomycin is hazardous to staff and the environment; use appropriate cytotoxic preparation, handling and disposal procedures.

Contraindications and cautions

• Hypersensitivity and breastfeeding apply to both selected products.
• Systemic Mitocin is contraindicated with pancytopenia, isolated leucopenia or thrombocytopenia, haemorrhagic diathesis, acute infection and renal impairment.
• Bladder-wall perforation contraindicates intravesical use. Cystitis is contraindicated for Mitomycin medac and described as a relative contraindication for Mitocin.

Monitoring

• For systemic therapy, check full blood count, renal and liver function before treatment; assess pulmonary function where underlying lung dysfunction is suspected.
• Monitor blood counts and renal function regularly during systemic treatment, recognising that marrow suppression may be delayed.
• Investigate haemolysis, thrombocytopenia and renal deterioration for microangiopathic haemolysis or haemolytic uraemic syndrome.
• After intravesical treatment, investigate severe or persistent pelvic or abdominal pain for extravasation, perforation, fistula or abscess.

Clinical pharmacology

Mitomycin is a bioreductively activated cytotoxic antibiotic. DNA alkylation and cross-linking inhibit DNA synthesis; peroxide-radical formation may contribute to DNA damage and organ toxicity. Intravesical absorption is low but systemic effects remain possible.

Formulation and product differences

• Mitomycin medac is an intravesical-only powder-and-solvent presentation supplied with an instillation system.
• Mitocin is a powder that may be prepared for intravenous injection, intravenous infusion or intravesical use.
• The products differ in their renal and hepatic impairment wording and in whether cystitis is an absolute or relative contraindication; consult the selected SmPC.

Injection

Route: Parenteral

Strengths: 20 mg