Patients taking nitrates to try to treat their heart disease are not eligible for Fildena XXX because this medication contains sildenafil citrate, which disrupts blood circulation. Such a combination is extremely harmful and causes sudden, severe drops in blood vessel pressure. For precautionary reasons, anyone prescribed Fildena XXX due to a history of cardiac problems, stroke, or arrhythmia should always speak with their doctor. Above everything, safety comes first.