If Fildena 50 contains sildenafil 50 mg, it should generally be stopped and medically reviewed if: You develop sudden vision loss or significant hearing loss. D DailyMed +1 You get an erection lasting more than 4 hours — seek emergency treatment rather than waiting for it to resolve. D DailyMed You develop chest pain, fainting, severe dizziness, or a serious allergic reaction. N nhs.uk You are prescribed nitrates (such as nitroglycerin/isosorbide) or riociguat; sildenafil should not be used with these medicines. D DailyMed Your doctor determines that ***** activity is unsafe because of your cardiovascular condition. D DailyMed There isn't a fixed number of days or weeks after which Fildena 50 must automatically be discontinued. For ED, sildenafil is normally taken only when needed, not more than once daily. N nhs.uk If you mean “How long can I safely use Fildena 50 regularly?”, tell me how often you're taking it (e.g., daily, 2–3 times/week), and I can explain.