There are no studies showing that tadalafil becomes less effective the more you take it. However, patients are required to follow the doctor’s instructions to ensure the safety of the medication. Tadalafil is a selective reversible inhibitor of cyclic guanosine monophosphate-specific phosphodiesterase 5 and is one of the most commonly used medications for erectile dysfunction in men. It is taken 1 hour before intercourse. Taking the drug, during intercourse, men can maintain a better erection hardness when sexually stimulated. If there is no sexual stimulation, the medication may not be able to act effectively. There are no studies that show that tadalafil becomes less effective the more you take it. However, it is clear that tadalafil can enhance the antihypertensive effects of nitrates. If a patient has recently taken nitrates, taking tadalafil may result in a decrease in blood pressure, among other things, and may be harmful to the patient. In addition, if the patient has a history of heart disease, it is important to follow the doctor’s instructions for medication, and not to use the medication at your own discretion, so as not to cause a dangerous event to occur.