Fildena 25 mg, which contains sildenafil, is used to treat erectile dysfunction (ED). While allergic reactions to sildenafil are rare, they can occur. Some potential allergic reactions and adverse effects include:

Rashes: Some individuals might develop skin rashes or hives as an allergic reaction to Fildena 25 mg.

Swelling: Rarely, allergic reactions might cause swelling of the face, lips, tongue, or throat, which can be serious and require immediate medical attention.

Itching: Itching or a feeling of tightness in the skin could also be a sign of an allergic reaction.

Difficulty Breathing: In severe cases, an allergic reaction might lead to difficulty breathing, which is a medical emergency.

Other Symptoms: Other possible reactions could include dizziness, headache, or gastrointestinal issues, though these are more common side effects rather than allergic reactions.

If you experience any symptoms that you suspect might be related to an allergic reaction, such as rash, itching, swelling, or difficulty breathing, it's important to seek medical attention immediately. Always consult with a healthcare provider before starting any new medication to ensure it’s safe for you and to discuss any potential allergic reactions or interactions with other medications you may be taking.