CARMUSTINE OBVIUS Powder and solvent for solution for infusion Ref.[6549] Active ingredients: Carmustine

Source: European Medicines Agency (EU)  Revision Year: 2018  Publisher: Obvius Investment B.V. De, Cuserstraat 93, 1081 CN, Amsterdam, The Netherlands

Pharmacodynamic properties

Pharmacotherapeutic group: Antineoplastic agents, alkylating agents, nitrosoureas
ATC code: L01AD01

Mechanism of action

Carmustine is a cell-cycle phase nonspecific antineoplastic agent of the nitrosourea type, which exerts tumor cytotoxicity via multiple mechanisms. As an alkylating agent, it can alkylate reactive sites on nucleoproteins, thus interfering with DNA and RNA synthesis and DNA repair. It is able to form interstrand crosslinks in DNA, which prevents DNA replication and transcription. In addition, carmustine is known to carbamoylate lysine residues on proteins causing irreversible inactivation of enzymes including glutathione reductase. The carbamoylating activity of carmustine is generally considered less significant than the alkylating activity in its action on tumors, but carbamoylation may serve to inhibit DNA repair.

Pharmacodynamic effects

The antineoplastic and toxic activities of carmustine may be due to its metabolites. Carmustine and related nitrosoureas are unstable in aqueous solutions and degrade spontaneously to reactive intermediates that are capable of alkylation and carbamoylation. The alkylating intermediates are believed to be responsible for the antitumor effect of carmustine. However, opinion is divided over the role of the carbamoylating intermediates as mediators of the biological effects of the nitrosoureas. On one hand, their carbamoylating activity was reported to contribute to the cytotoxic properties of their parent drugs by inhibiting DNA repair enzymes. On the other hand, it has been speculated that the carbamoylating species may mediate some of toxic effects of carmustine.

Carmustine crosses the blood-brain barrier readily because of its lipophilic nature.

Paediatric population

Carmustine Obvius should not be used in children and adolescents due to high risk of pulmonary toxicity.

Pharmacokinetic properties

Distribution

Intravenously administered carmustine is rapidly degraded, with no substance intact detectable after 15 minutes. Because of the good lipid solubility and the lack of ionisation at the physiological pH, carmustine is very well transferred through the blood-brain barrier. Levels of radioactivity in the cerebrospinal fluid are at least 50% higher than those measured concurrently in plasma. The kinetic of carmustine in humans is characterised by a two-chamber model. After the intravenous infusion over 1 hour, the carmustine-plasma level drops in a biphasic manner. The half-life α is 1-4 minutes and the half-life β is 18-69 minutes.

Biotransformation

It is presumed that the metabolites of carmustine cause its antineoplastic and toxic activity.

Elimination

Approximately 60-70% of a total dose is excreted in the urine in 96 hours and about 10% as respiratory CO2. The fate of the remainder is undetermined.

Preclinical safety data

Carmustine was embryotoxic and teratogenic in rats and embryotoxic in rabbits at dose levels equivalent to the human dose. Carmustine affected the fertility of male rats at doses higher than the human dose. Carmustine, at clinically relevant dose levels, was carcinogenic in rats and mice.

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