Before taking Prevacid SoluTab (lansoprazole), you should know that liver or kidney disease may impact the effectiveness of this drug. Tell your doctor if you have liver or kidney disease prior to taking this drug. If you have a condition called phenylketonuria (PKU), you may not be able to take this drug because it contains phenylalanine, which can make PKU worse. PKU is a genetic disorder in which your body accumulates too much phenylalanine. You also need to know that this drug belongs to the drug class known as proton pump inhibitors. Recently, the US Food and Drug Administration (FDA) issued a warning that use of this class of drug may increase the risk for hip, wrist, and spine fractures.