Vidalista 20 contains tadalafil 20 mg, a medicine used for erectile dysfunction. It can affect blood pressure because tadalafil relaxes blood vessels, which may cause a temporary drop in blood pressure. Typical timing: Starts affecting blood pressure: usually within about 30–60 minutes after taking it. Greatest effect: often around 1–4 hours after the dose. How long the effect can last: tadalafil can remain active in the body for up to 36 hours, so mild blood-pressure effects may be possible during that period. The blood-pressure drop is usually small in healthy people, but it can be more significant if combined with: Nitrate medicines (such as nitroglycerin or isosorbide) — this combination can cause a dangerous blood-pressure fall. Alpha-blockers (some medicines for prostate problems or blood pressure). Multiple blood-pressure-lowering medicines. Heavy alcohol use or dehydration. Possible signs of low blood pressure include: Dizziness or lightheadedness Fainting Blurred vision Unusual weakness If you take Vidalista 20 and feel faint, have chest pain, or have a severe reaction, seek medical help. If you tell me your age, blood pressure readings, and any medicines you take (especially heart or BP medicines), I can help assess whether Vidalista 20 is likely to affect you more strongly.