Vidalista 80 mg contains tadalafil, a PDE-5 inhibitor used to treat erectile dysfunction. Like any medication, it can cause allergic reactions, although they are considered uncommon. Possible signs of an allergic reaction may include: Skin rash, itching, or hives Swelling of the lips, face, tongue, or throat Difficulty breathing or swallowing Severe dizziness or fainting A severe allergic reaction (such as swelling of the throat or trouble breathing) requires urgent medical attention. More common side effects of tadalafil are not allergies Vidalista 80 mg may include: Headache Flushing Indigestion Nasal congestion Back pain or muscle aches Dizziness Vidalista 80 mg is a high-strength tadalafil dose, and higher doses may increase the chance of side effects. It should be used only with medical guidance, especially if you have heart conditions, low blood pressure, or take other medicines. If you have previously had an allergic reaction to tadalafil or any ingredient in the tablet, avoid using it and consult a healthcare professional.