Study of Valproic Acid (VPA) vs Placebo to Shorten Time of Indwelling Pleural Catheter

Baseline Fluid Collection: Before receiving the study drug or the placebo, pleural fluid will be drained from your catheter to be compared to fluid collected later in the study. Study Groups: You will be randomly assigned (as in the flip of a coin) to 1 of 2 study groups. Group 1 will take a placebo 3 times a day for 10 weeks while an indwelling pleural catheter drains pleural fluid. If you are in Group 2, you will take VPA 3 times a day for a total of 10 weeks while an indwelling pleural catheter drains pleural fluid. Study Drug Administration: Within 48 hours of collection of baseline fluid, all study participants will take either placebo or VPA capsules 3 times a day by mouth with food. If you tolerate the starting dose well and the study doctor thinks it is in your best interest, your dose level will be doubled. You may be contacted at a later time by telephone to discuss how you are doing with the medicine. If your doctor feels your dose should be doubled, he/she will talk to you about it at this time. Neither you nor the study staff will know if you are receiving the study drug or the placebo. However, if needed for your safety, the study staff will be able to find out what you are receiving. You will be given a pill diary to record the time you take each dose. You will need to bring the diary with you to every clinic visit. The fluid drained from the catheter will be collected and studied to see if the how the VPA is working and how it may affect the time you will need to have an indwelling pleural catheter. You will also be asked to keep a daily diary of drainage with the date and amount of fluid drained each day at home. You will bring the drained fluid from the day before to each clinic visit to give to the research team. You will be given special containers to store the drained fluid. You will only save fluid from the day before each clinic visit. On the other days you will write down the amount of drained fluid that was collected, then you can throw away the fluid. You must bring the daily drainage diary to each clinic visit. Study Visits: At Weeks 2, 6, and 10 while you are receiving the study drug: * You will have a complete physical exam including weight and vital signs and a medical history. * You will complete the same questionnaires that you completed at screening. * Your performance status will be recorded. * Blood (about 2 tablespoons) will be drawn for routine tests. * You will have a chest X-ray to check the status of the disease. At Week 10 only, you will have a computed tomography (CT) scan of the chest to check the status of the disease. Length of Study: You will be taken off study after the indwelling pleural catheter has been removed. You will no longer be able to take part in this study if the disease gets worse, if intolerable side effects occur, or if you are unable to follow study directions. Your active participation in this study will be over after Week 10. Follow-Up Medical Record Review: After the 10 week visit the study personnel will continue to review your medical record to learn when the indwelling pleural catheter was removed. Your medical record information will continue to be reviewed for up to 5 years. This is an investigational study. VPA is FDA approved and commercially available for the treatment of epileptic seizures and mania in bipolar disorder. VPA use in patients using pleural catheters is for research purposes only. Up to 76 patients will take part in this study. All will be enrolled at MD Anderson.