Since you are elderly and have a kidney problem, your doctor will prescribe a low dose of Valtoval 500 Tablet. You must drink plenty of water regularly during the day while taking Valtoval 500 Tablet. This will help to reduce the side effects that can affect the kidney or nervous system. Your doctor will closely monitor you for signs of any side effects which may include feeling confused, agitated or unusually sleepy, or drowsy. If you develop any of these effects contact your doctor immediately.