Mechlorethamine, also known as nitrogen mustard, is a chemotherapy drug with a varied history of availability in the United States. While the injectable form is no longer available, a topical gel formulation is still used for a specific type of cancer. Understanding this difference is crucial for patients and medical professionals.
The Discontinuation of Injectable Mechlorethamine (Mustargen)
The injectable version of mechlorethamine, marketed as Mustargen, was used for decades to treat various cancers, including Hodgkin's and non-Hodgkin's lymphomas, and certain leukemias. However, due to the development of newer treatments and declining demand, the manufacturer discontinued Mustargen in 2018. This decision was based on low market demand, not safety concerns. Resources like MedlinePlus and the Veterans Affairs Health Library no longer provide updated information on this discontinued formulation.
The Availability of Topical Mechlorethamine Gel (Valchlor)
Despite the injectable form's discontinuation, mechlorethamine is still available in the US as a topical gel called Valchlor. Approved by the FDA in 2013, Valchlor is specifically indicated for treating early-stage mycosis fungoides-type cutaneous T-cell lymphoma (MF-CTCL) in patients who have already received other skin therapies. Valchlor is applied directly to the skin to target localized lesions and has minimal systemic absorption, which helps reduce widespread chemotherapy side effects. It is exclusively available through specialty pharmacies.
How Mechlorethamine Works
As an alkylating agent, mechlorethamine damages cancer cell DNA, preventing growth and division. The topical gel delivers this effect directly to affected skin cells in MF-CTCL.
Differences Between the Discontinued Injectable (Mustargen) and Available Topical (Valchlor)
| Feature | Mustargen (Injectable) | Valchlor (Topical Gel) |
|---|---|---|
| Availability in US | Discontinued since 2018 | Currently available |
| Indication | Hodgkin's lymphoma, non-Hodgkin's lymphoma, leukemia, etc. | Early-stage mycosis fungoides-type CTCL |
| Formulation | Intravenous or intracavitary injection | Topical gel applied to the skin |
| Availability Route | Was available through standard pharmacy channels | Available only through specialty pharmacies |
| Side Effects | Systemic: nausea, vomiting, bone marrow suppression, hair loss | Localized: skin irritation, dermatitis, itching, blistering |
| Systemic Absorption | Designed for systemic absorption | Minimally absorbed systemically |
Important Considerations for Topical Mechlorethamine (Valchlor)
Safe handling and application of Valchlor are crucial. Caregivers should use disposable nitrile gloves, and hands must be washed thoroughly after use. The gel is flammable and should not be used near heat or open flames until dry. It is applied once daily to dry skin, waiting at least 30 minutes after washing before applying and at least 4 hours after applying before washing the treated area. Valchlor requires refrigeration. It is for external use only; contact with eyes, nose, or mouth necessitates immediate rinsing and medical attention.
Alternatives for Systemic Treatment
For conditions previously treated with injectable mechlorethamine, alternative systemic chemotherapy drugs like cyclophosphamide or chlorambucil are available. An oncologist can determine the best current treatment plan for a specific condition.
Conclusion: Navigating Mechlorethamine's Availability
So, is mechlorethamine available in the US? Yes, but only as the topical gel Valchlor for early-stage mycosis fungoides-type CTCL. The injectable form, Mustargen, is discontinued. Patients and healthcare providers should consult with a qualified professional for guidance on Valchlor use or alternative treatments.
