Silditop 100 contains sildenafil citrate 100 mg, a medicine used for erectile dysfunction (ED). Self-medication should be avoided by people who may have a higher risk of serious side effects or drug interactions. People who should not self-medicate with Silditop 100 include: Anyone taking nitrate medicines for chest pain (such as nitroglycerin or isosorbide) — the combination can cause a dangerous drop in blood pressure. People using riociguat (a medicine for certain types of pulmonary hypertension), because it can also cause excessive blood-pressure lowering with sildenafil. People with serious or unstable heart conditions, especially if a Silditop 100 has advised avoiding sexual activity. Those with recent heart attack, stroke, or significant cardiovascular problems who have not been medically assessed. People with very low blood pressure or uncontrolled blood pressure problems. People with severe liver disease or severe kidney impairment, as sildenafil levels can be higher and dose adjustments may be needed. People with certain eye conditions (such as rare inherited retinal disorders) or a history of certain serious vision problems. Anyone already taking other ED medicines (such as tadalafil, vardenafil, or other sildenafil products) unless specifically directed by a doctor. Extra caution is needed if you take alpha-blockers for prostate problems or blood pressure, multiple blood-pressure medicines, or medicines that affect sildenafil metabolism.