In order to treat erectile dysfunction sildenafil can not be taken for a long time, but for the treatment of pulmonary hypertension it can be taken for a long time until the symptoms subside and disappear before the drug can be properly discontinued. Sildenafil can be used for the treatment of erectile dysfunction and the treatment of pulmonary arterial hypertension, due to the use of sildenafil may occur dizziness, headache, insomnia, panic, palpitations, tachycardia, lower blood pressure, diarrhea and other adverse reactions, so if it is for the treatment of erectile dysfunction should not be taken regularly, so as not to increase the chances of adverse reactions. Patients with pulmonary arterial hypertension need to control the pressure of the pulmonary arteries, can only be taken for a long time, but the specific use of the need to be under the guidance of a doctor. Pulmonary arterial hypertension may appear dyspnea, chest tightness, fatigue, chronic fatigue, hoarseness, cough, chest pain, edema and other symptoms, in the long term, if these symptoms subside or even disappear, then you can consult a doctor to reduce or stop the treatment. Sildenafil is contraindicated in people who are allergic to sildenafil and those who are using nitrate drugs or guanylate cyclase stimulators, women, children and other people.