Accidental intramuscular injection of mechlorethamine.

A 55-year-old man with chronic, active diffuse psoriasis was accidentally given 30 mg of mechlorethmine deep into the buttock muscles. About 5 hours after the intramuscular (IM) mechlorethamine injection, 1/6 M sodium thiosulfate was infused around the intramuscular site. Although systemic responses to the mechlorethamine developed, the expected muscular and adjacent skin destruction did not occur. Instead, IM mechlorethamine induced only minimal local tenderness.