Tadalista CT 20 mg (tadalafil 20 mg) should seek medical advice if they experience concerning side effects, have underlying health conditions, or take medicines that may interact with tadalafil. 1. Seek emergency medical care immediately Erection lasting 4 hours or longer, even if it is not painful. Chest pain, fainting, or severe difficulty breathing. Sudden loss or major change of vision or hearing. Severe allergic reaction, such as swelling of the face, tongue or throat, or difficulty breathing. If you develop chest pain after taking tadalafil, call emergency services and tell the medical team when you took it. Do not take nitrates such as nitroglycerin yourself. 2. Contact a doctor promptly Seek medical advice if you experience: Persistent or severe headache, dizziness, or back pain. Blurred vision, ringing in the ears, or reduced hearing. Repeated palpitations or unusual shortness of breath. Side effects that persist, worsen, or interfere with daily activities. MedlinePlus +1 3. Speak to a doctor before taking it if you: Have diabetes, heart disease, kidney or liver problems. Take medicines for high blood pressure or an enlarged prostate. Use nitrate medicines or riociguat. Have had a previous prolonged erection or sudden vision loss. Diabetes alone does not necessarily prevent tadalafil use, but related heart, blood-vessel and kidney complications can affect its safety.