Acute and subacute toxicities

The most common acute side effect associated with intrathecal chemotherapy alone is seizures. Up to 5% of nonirradiated patients with ALL treated with frequent doses of intrathecal chemotherapy will have at least one seizure during therapy.[12] Higher rates of seizure were observed with consolidation regimens that included 12 courses of intermediate-dose IV methotrexate (1 g/m2) given every 2 weeks with intrathecal chemotherapy.[29] Intrathecal and high-dose IV methotrexate have also been associated with a stroke-like syndrome, which, in most cases, appears to be reversible.[30]

Patients with ALL who develop seizures during the course of treatment and who receive anticonvulsant therapy should not receive phenobarbital or phenytoin as anticonvulsant treatment, as these drugs may increase the clearance of some chemotherapeutic drugs and adversely affect treatment outcome.[31]