Suhagra 25 mg contains sildenafil, and it can cause side effects even though 25 mg is a relatively low dose. Common side effects Usually mild and temporary: Headache Facial flushing/warmth Dizziness Indigestion or stomach upset Nausea Stuffy nose Blurred or altered vision Less common Suhagra 25 mg important Seek urgent medical attention for: Chest pain Fainting or severe dizziness Sudden loss/decrease of vision or hearing An erection lasting more than 4 hours Very important: Sildenafil should not be taken with nitrate medicines used for chest pain (such as nitroglycerin), because the combination can cause a dangerous drop in blood pressure. It can also interact with some blood-pressure medicines. If you tell me your age, whether you take any regular medicines, and whether you have BP/heart problems, I can tell you what specific precautions apply to you.