A patient will begin taking sildenafil (Viagra) for penile erectile dysfunction (ED). What is the nurse's priority teaching point about this drug?

Question

A) He will have an erection exactly 1 hour after taking the drug.
B) The drug should not be taken with a penile implant or any anatomic penile obstruction.
C) Avoid drinking grapefruit juice for 2 days before and after taking the drug.
D) It is important to know the cause of ED because sildenafil does not treat all causes.

Answer 1

C
Feedback:
Patients who are using sildenafil need to be advised to avoid drinking grapefruit juice while using the drug. Grapefruit juice can cause a decrease in the metabolism of the PDE5 inhibitor, leading to increased serum levels and a risk of toxicity. They need to know that it takes 48 hours for grapefruit juice to be processed by the body, so they need to avoid it for several days before and after taking the drug. The patient should be screened for penile implants, anatomic penile obstruction, and the cause of ED before the drug is prescribed. Sildenafil has a median onset of 27 minutes and duration of 4 hours so the patient may have an erection as early as 27 minutes after taking it.