Melphalan

Melphalan In Dogs & Cats: Uses, Dosage and Side Effects

Overview

• Forms inter- and intrastrand cross-links with DNA, resulting in inhibition of DNA synthesis and function

Uses of Melphalan

• Treatment of multiple myeloma.
• May also be used as a substitute for cyclophosphamide in the treatment of canine lymphoma and in some rescue protocols for lymphoma.
• Treatment of some solid tumours (e.g. ovarian carcinoma, osteosarcoma, pulmonary and mammary neoplasia).
• Take care in dosing small dogs using their body surface area as there is a risk of overdose due to the tablet sizes (tablets should not be split).
• Give tablets on an empty stomach.

Dose of Melphalan in Dogs and Cats

Dogs:

Myeloma:

• 2 mg/m2 p.o. q24h for 1–2 weeks then reduce to 2–4 mg/m2 p.o. q48h.
• Or 0.1 mg/kg p.o. q24h for 10 days then 0.05 mg/kg p.o. q24–48h thereafter.
• Or 7 mg/m2/day (rounded to the nearest whole 2 mg tablet) for 5 consecutive days every 21 days.
• Often used with prednisolone, see specialist texts for regimes.

Lymphoma:

• 20 mg/m2 q14d.

Adjunctive treatment of ovarian carcinoma, lymphoreticular neoplasms, osteosarcoma, mammary/pulmonary neoplasia:

• 2–4 mg/m2 p.o. q48h.

Cats:

Chronic lymphocytic leukaemia:

• 2 mg/m2 p.o. q48h, with or without prednisolone.

Multiple myeloma:

• 0.1 mg/kg p.o. q24h for 14 days then q48h until improvement or leucopenia is detected.
• Cats already with leucopenia and anaemia should be treated q72h.
• Often used with prednisolone, see specialist texts for regimes.

Side Effects of Melphalan in Dogs and Cats

• Myelosuppression is dose-limiting toxicity with leucopenia and thrombocytopenia; the effect may be prolonged and cumulative.
• GI adverse reactions include anorexia, nausea and vomiting.
• Pulmonary infiltrates or fibrosis can also occur.
• Oral ulceration is seen in humans.

Contraindications of Melphalan in Dogs and Cats

• Bone marrow suppression, concurrent infection and impaired renal function.

Some Notes:

• Cimetidine decreases the oral bioavailability of melphalan.
• Steroids enhance the antitumour effects of melphalan.
• In humans, ciclosporin enhances the risk of renal toxicity.