dactinomycin: clinical use

Prescribing considerations

• Restrict preparation and administration to staff experienced with cytotoxic chemotherapy and hazardous-drug handling.
• Toxicity may emerge after treatment and peak later, requiring continued clinical observation.
• Use in infants under 12 months only when benefit outweighs the greater toxicity risk; older adults may have increased myelosuppression.
• Review previous or concurrent radiotherapy carefully because dactinomycin potentiates radiation toxicity.
• Treat suspected extravasation immediately and arrange close follow-up because tissue injury can progress.

Contraindications and cautions

• Hypersensitivity to dactinomycin or an excipient
• Active varicella or herpes zoster infection
• Breastfeeding

Monitoring

• Full blood count, including white-cell and platelet counts
• Liver and kidney function
• Mucositis, diarrhoea and other gastrointestinal toxicity
• Infusion site during and after administration
• Features of infection, bleeding and hepatic veno-occlusive disease

Clinical pharmacology

Dactinomycin binds DNA and inhibits DNA-dependent RNA synthesis. It is minimally metabolised, concentrates in nucleated cells and does not appear to cross the blood–brain barrier appreciably.

Formulation and product differences

• The selected UK product is a yellow-orange lyophilised powder containing mannitol and no preservative.
• Reconstitute only with preservative-free Water for Injections; solutions containing benzyl alcohol or parabens can cause precipitation.
• The reconstituted solution should be clear and gold-coloured, and unused product must be discarded.

Injection

Route: Parenteral

Strengths: 500 micrograms