Tadalafil, the active ingredient in medications like Cialis, can cause a mild, transient decrease in blood pressure. It's important to note that this effect is generally modest and is more likely to occur in individuals who are already taking medications that affect blood pressure or nitrates. If you have low blood pressure or are taking medications for other health conditions, it's crucial to consult with your healthcare provider before using tadalafil. They can assess your specific health situation and determine whether tadalafil is a safe and appropriate option for you. Never self-prescribe or adjust medication without professional medical advice. Always follow your healthcare provider's guidance for the safest and most effective use of tadalafil.