Taking Fildena 100mg is safe and does not affect sperm counts. However, you should consult your doctor if you are pregnant or breastfeeding, or if you have a medical condition. As a precaution, avoid drinking grapefruit juice and consuming alcoholic beverages. These can interact with the drug and activate unfavorable side effects. As with any prescription medication, Fildena 100mg takes approximately half an hour to take effect. The effects last up to four hours. For the best results, you should take the drug as prescribed by your doctor. It's safe for men with erectile dysfunction, but you should follow the instructions carefully.