Fildena 25 mg (which contains Sildenafil, the same active ingredient as Viagra) is used to treat erectile dysfunction (ED) and is generally considered safe for most individuals. However, there are a few important restrictions and precautions to be aware of:

Heart Conditions: If you have heart disease, a history of heart attacks, or other cardiovascular conditions, you should consult with your doctor before taking Fildena. This medication can cause a temporary drop in blood pressure, which could be dangerous for people with heart issues.

Nitrate Medications: If you're taking any form of nitrate medications (commonly prescribed for chest pain or angina), you must not use Fildena. The combination can cause a severe and dangerous drop in blood pressure.

Low Blood Pressure: If you already have low blood pressure (hypotension), you should avoid using Fildena 25mg or take it only under a doctor's supervision. The medication can lower blood pressure even further.

Liver or Kidney Disease: If you have liver or kidney conditions, your doctor may need to adjust the dosage of Fildena or monitor you more closely.

Other Medications: If you are on medications for high blood pressure, antifungals, certain antibiotics, or protease inhibitors (used for HIV), you should talk to your doctor, as they may interact with Fildena.

Age Considerations: Older adults may be more sensitive to the effects of Fildena, especially those over 65 years old, so a dose adjustment may be needed.

Vision Issues: Sildenafil can cause rare vision problems or increase the risk of certain eye conditions like non-arteritic anterior ischemic optic neuropathy (NAION), so if you experience sudden vision loss or changes in vision, you should seek medical attention immediately.

Alcohol and Grapefruit: Drinking alcohol or consuming grapefruit while taking Fildena can increase the risk of side effects like dizziness or headaches, so moderation is advised.

It's essential to follow your doctor’s recommendations and get personalized advice based on your health status and any medications you're currently taking.