Melphalan

Key facts

• Melphalan is a cytotoxic (alkylating) chemotherapy drug used mainly for multiple myeloma, and at high intravenous doses as conditioning before a stem-cell transplant.
• It is given as tablets or an intravenous infusion in cycles planned by a cancer specialist, timed around your blood counts.
• Its most important risk is severe bone marrow suppression, low white cells, red cells and platelets, which requires regular blood tests; it also raises the long-term risk of secondary cancers such as leukemia.
• Seek urgent care for fever, unusual bleeding or bruising, or severe breathlessness.

What melphalan treats

Melphalan treats multiple myeloma, a cancer of plasma cells in the bone marrow, and some ovarian cancers. It is also used as high-dose conditioning chemotherapy before an autologous stem-cell transplant. It is a cytotoxic drug reserved for cancer treatment, not a general anti-inflammatory or pain medicine.

How melphalan works

Melphalan is an alkylating agent that attaches chemical groups to DNA and cross-links the two strands, so cells cannot copy their genetic material or divide. Cancer cells divide faster than most normal cells and are hit hardest, but healthy fast-dividing tissue such as bone marrow is damaged too.

Before you take it

• Do not take melphalan during pregnancy; it can seriously harm a developing baby, and effective contraception is required during treatment and for a period afterward, for patients and partners.
• Tell your care team about any infection, low blood counts, or recent or planned vaccination; live vaccines should be avoided during treatment.
• Blood counts are checked before every dose, and treatment may be delayed or the dose reduced if counts are too low.
• Kidney function affects dosing, since part of melphalan's clearance depends on the kidneys.

Side effects

Common effects include nausea, vomiting, loss of appetite, fatigue, mouth sores and hair thinning.

Stop and seek urgent medical care for:

• Fever or chills, which can signal infection from low white blood cells.
• Unusual bleeding, bruising, or blood in urine or stool, which can signal low platelets.
• Severe shortness of breath or chest pain.

Safety essentials

• Melphalan suppresses bone marrow function; regular blood counts throughout treatment are mandatory to catch dangerously low counts early.
• It raises the lifetime risk of secondary cancers, including leukemia, particularly with prolonged or high-dose use.
• Avoid pregnancy during treatment; effective contraception is required for both patients and partners.

This page is educational and does not replace advice from a doctor or pharmacist who knows your health history.