The hydrochloride salt of a methylhydrazine derivative with antineoplastic and mutagenic activities. Although the exact mode of cytotoxicity has not been elucidated, procarbazine, after metabolic activation, appears to inhibit the trans-methylation of methionine into transfer RNA (t-RNA), thereby preventing protein synthesis and consequently DNA and RNA synthesis. This agent may also undergo auto-oxidation, resulting in the formation of cytotoxic free radicals which damage DNA through an alkylation reaction. or A drug that is used to treat advanced Hodgkin lymphoma and is being studied in the treatment of other types of cancer. Procarbazine hydrochloride blocks cells from making proteins and damages DNA. It may kill cancer cells. It is a type of antineoplastic agent and a type of alkylating agent. Also called Matulane.