The invention provides methods for increasing the activity of an inhibitory RNA (RNAi) in a subject requiring administering one or more poly-ADP-ribose polymerase (PARP) inhibitors and/or one or more PARG activators to the subject. The invention also provides methods for increasing the activity of an inhibitory RNA in a cell or cell population requiring contacting a cell or cell population with one or more PARP inhibitors and/or one or more PARG activators. The invention further provides compositions and kits containing one or more PARP inhibitors and/or one or more PARG activators.