Pentoxia 400 mg ER Tablet 10's is used to treat pain in the legs due to insufficient blood flow (intermittent claudication). It also reduces cramping, numbness, or weakness in the legs on walking in such patients. It works by decreasing the viscosity (thickness) of blood, allowing it to pass more easily through the blood vessels, especially in the small blood vessels of the hands and feet. It can also increase the distance you can walk without pain since it improves your legs blood circulation. It is recommended in patients whose pain has not improved even after lifestyle changes like quitting smoking and doing regular exercise. In some cases, it may cause side effects such as nausea, vomiting, diarrhoea, headache, lightheadedness, sleep problems, intrahepatic cholestasis (removal of bile from the liver is blocked), abdomen pain, constipation, and urine discolouration.