Tazzle 20 mg contains tadalafil, a PDE5 inhibitor used for erectile dysfunction (ED). Whether it is safe for someone with heart rhythm issues (arrhythmias) depends on several factors.  Key Considerations for Heart Rhythm Issues Underlying heart condition Men with serious arrhythmias, unstable angina, or recent heart attack should not take tadalafil without a cardiologist’s approval. Tadalafil affects Tazzle 20 mg vessels and can lower blood pressure slightly, which may worsen some arrhythmias. Medications Nitrates (nitroglycerin, isosorbide mononitrate/dinitrate) – absolutely contraindicated with tadalafil due to dangerous drops in blood pressure. Certain antiarrhythmic drugs (like amiodarone, sotalol, flecainide) may interact indirectly, increasing risk of dizziness or hypotension. Dose considerations 20 mg is a standard on-demand dose. For people with heart rhythm issues, a lower starting dose (10 mg) may be safer. Always start under doctor supervision.