Tadarise Pro 40 mg contains tadalafil, and headache is a well-known side effect of tadalafil. In clinical data for tadalafil 40 mg, headache occurred in about 42% of patients in one study. D DailyMed +1 A few important points: 40 mg is a relatively high tadalafil dose for erectile dysfunction; usual as-needed ED doses are 10–20 mg. Headache can be accompanied by flushing, dizziness, nasal congestion, or indigestion. Drinking plenty of water and avoiding excessive alcohol may help, but don't take another tadalafil dose to compensate. Do not combine tadalafil with nitrates (such as nitroglycerin/isosorbide) because of the risk of a dangerous drop in blood pressure. D DailyMed Seek urgent medical attention for severe chest pain, fainting, sudden vision/hearing loss, or an erection lasting over 4 hours. D DailyMed If you've already taken Tadarise Pro 40 mg and now have a headache, tell me when you took it, how severe the headache is (1–10), and whether you have dizziness or low blood pressure, and I can advise you what to do next.