- Have received chloramphenicol, cisplatin, clioquinol, dapsone, diphenylhydantoin, disulfiram, ethionamide, glutethimide, gold, hydralazine, isoniazid, metronidazole, pyridoxine, sodium cyanate, thalidomide, vincristine, or zalcitabine within 30 days of study entry. In certain cases, patients taking these drugs may still be eligible.