Taking two Fildena Professional pills simultaneously increases the likelihood of experiencing side effects. Fildena Professional contains sildenafil citrate, which is used to treat erectile dysfunction. Common side effects of sildenafil citrate include headache, flushing, dizziness, nasal congestion, nausea, and visual changes. However, the severity and frequency of these side effects can vary from person to person. It’s important to consult with a healthcare professional before increasing the dosage of any medication, as they can provide guidance on the appropriate dosage and monitor for any adverse effects.