<qa>  What is the name of the medication that may alter ZD1839 pharmacokinetics- Patients must not take the following medications that may alter ZD1839 pharmacokinetics while enrolled in this trial: phenytoin, carbamazapine, phenobarbitol, rifampicin, and St. Johns Wort, oxcarbazepine, rifapentine, modafinil, and griseofulvin 