Ibenzmethyzine Other names: Procarbazine

Procarbazine, a methylhydrazine derivative, is a cytostatic agent with weak MAO inhibitor properties. Its exact mode of action on tumour cells is unknown. It may be effective in patients who have become resistant to radiation therapy and other cytostatic agents.

Children

Procarbazine in combination with other anti-tumour agents has been investigated in uncontrolled studies in children with brain tumours. Favourable partial responses, complete responses and survival rates have been documented. Paediatric data from randomised controlled clinical studies are limited.

Absorption

Procarbazine is readily absorbed from the gastrointestinal tract.

Distribution

Peak plasma levels are reached at 0.5-1 hour after oral administration. Procarbazine quickly equilibrates between the blood and cerebrospinal fluid (CSF). Peak CSF levels are achieved 30-90 minutes after oral administration.

Biotransformation

Procarbazine is rapidly metabolised, the primary circulating metabolite is the azo derivative while the major urinary metabolite has been shown to be N-isopropyl-terephthalamic acid.

Elimination

A plasma half-life of about 10 minutes has been reported.

Approximately 5% of procarbazine is excreted unchanged in the urine. The remainder is oxidised to N-isopropylterephthalamic acid and excreted in the urine, up to about 70% of a dose being excreted in 24 hours. Some of the drug is excreted as carbon dioxide and methane via the lungs.

Non-clinical data reveal no special hazard for humans based on conventional studies of safety pharmacology, repeated dose toxicity, genotoxicity, carcinogenic potential, toxicity to reproduction, other that already included in other sections of the summary.