Captopril in Treating Patients With Non-Small Cell Lung Cancer or Limited-Stage Small Cell Lung Cancer That Has Been Previously Treated With Radiation Therapy With or Without Chemotherapy

RATIONALE: Captopril is a drug that may be able to decrease side effects caused by radiation therapy, and may improve the quality of life of patients with non-small cell lung cancer or limited-stage small cell lung cancer. PURPOSE: This randomized phase II trial is studying how well captopril works in decreasing side effects and improving the quality of life in patients who have received radiation therapy with or without chemotherapy for stage I, stage II, or stage IIIB non-small cell lung cancer or limited-stage small cell lung cancer.