Сytotoxic Drugs in Anesthetic Practice
Cytotoxic drugs used in the treatment of malignancy and as immunosuppressive drugs. All may cause nausea and vomiting and bone marrow suppression; most are teratogenic and require careful preparation by trained personnel. Extravasation of iv drugs may cause severe tissue necrosis. Some have side effects of particular anaesthetic/ICU relevance:
◗ alkylating agents (act by damaging DNA and impairing cell division): cyclophosphamide may prolong the effect of suxamethonium; busulfan may cause pulmonary fibrosis. Chlorambucil may rarely cause severe skin reactions.
◗ cytotoxic antibiotics: doxorubicin may cause cardiomyopathy; bleomycin may cause pulmonary fibrosis.
◗ antimetabolites: methotrexate may cause pneumonitis.
◗ vinca alkaloids: vincristine and vinblastine may cause autonomic and peripheral neuropathy.
◗ others: cisplatin may cause nephrotoxicity, ototoxicity and peripheral neuropathy; procarbazine has monoamine oxidase inhibitor effects; azathioprine may cause hepatic impairment, nephritis and rarely pneumonitis.
O2 therapy has been implicated in exacerbating the pulmonary fibrosis caused by cytotoxic drugs.
Specific guidelines (issued by the Committee on the Review of Medicines) exist for the handling of cytotoxic drugs. These include the necessity for trained staff to administer drugs, designated areas for drug reconstitution, protective clothing, eye protection, safe disposal of waste material and avoidance of handling cytotoxics by pregnant staff.
Accidental intrathecal (instead of intravenous) injection of vincristine during combination chemotherapy almost inevitably results in death; in the UK, anaesthetists have been involved in such errors. Totally incompatible intrathecal/intravenous connections have been developed as a result.
