Opsutan Tablet is a prescription medicine used to treat pulmonary arterial hypertension (high pressure in the blood vessels that carry blood from the heart to the lungs). It even helps to improve your quality of life, exercising ability and delay in disease progression. Opsutan Tablet is given alone or in combination with some other medicines. It should be taken with or without food. This medicine should be used regularly to get the most benefit from it. The dose and how often you take it depends on what you are taking it for. Your doctor will decide how much you need to improve your symptoms. You should take this medicine for as long as it is prescribed for you. The most common side effects of this medicine include headache, swelling of the legs and ankles(edema), and inflammation of the airways. If these bother you or appear serious, let your doctor know. There may be ways of reducing or preventing them. Some serious side effects which mean your doctor should know immediately include Anemia (low number of red blood cells) and abnormal liver function such as nausea, vomiting, dark urine, fever, and dark urine. Your doctor might check you for blood tests to check for anemia and liver function. Before taking this medicine, let your doctor know if you have liver dysfunctioning. Inform your doctor if you are pregnant or breastfeeding. Your doctor should also know about all other medicines you are taking as many of these may make this medicine less effective or change the way it works. You must avoid driving if this medicine makes you feel dizzy.