Penegra 50 mg contains sildenafil, a medicine commonly prescribed for erectile dysfunction (ED). For first-time users, buying the medicine safely is just as important as understanding how it works. Before purchasing Penegra 50 mg, consult a qualified healthcare professional. Sildenafil is not suitable for everyone, particularly people taking nitrate medicines such as nitroglycerin, because the combination can cause a dangerous drop in blood pressure. Tell your doctor about heart conditions, blood-pressure problems, and all prescription medicines, over-the-counter products, and supplements you use.