Mechlorethamine extravasation

The antidote of choice for mechlorethamine extravasations is sodium thiosulfate. This agent binds alkylating agents, resulting in neutralization to inactive compounds that are then excreted. Sodium thiosulfate also may be effective for high-concentration cisplatin or dacarbazine extravasations. 

Anthracycline, mechlorethamine, and vinca alkaloid extravasations typically cause immediate pain. 

Pharmacokinetics Mechlorethamine is very unstable, and solutions must be made up just prior to administration. Mechlorethamine is also a powerful vesicant (blistering agent), and is administered only IV, because it can cause severe tissue damage if extravasation occurs. Because of its reactivity, hardly any drug is excreted. 

Local reactions to extravasation of mechlorethamine into the subcutaneous tissue result in a severe, brawny, tender induration that may persist for a long time. If the local reaction is unusually severe, a slough may result. If it is obvious that extravasation has occurred, the involved area should be promptly infiltrated with a sterile isotonic solution of sodium thiosulfate (167 mM) an ice compress then should be applied intermittently for 6 to 12 hours. Thiosulfate reacts avidly with nitrogen mustard and thereby protects tissue constituents. 

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