For most people, sildenafil should not be taken more than once in 24 hours. Taking it every day without medical advice can increase the risk of side effects such as headache, flushing, indigestion, nasal congestion, dizziness, and changes in vision. Higher exposure may also increase the likelihood or severity of adverse effects.

If you need ED treatment frequently, speak with a doctor about a suitable treatment schedule. Depending on your circumstances, a healthcare professional may consider a different sildenafil dose or another ED treatment designed for more regular use. Do not increase the dose because the medication seems less effective.

It is particularly important to seek medical advice before using sildenafil if you have heart or blood-pressure problems, significant liver or kidney disease, or take medicines such as nitrates for chest pain. Sildenafil should not be combined with nitrates because the combination can cause a dangerous drop in blood pressure. It should also not be combined with other PDE5 inhibitors or other ED medicines unless specifically directed by a healthcare professional.