A client has been taking Viagra and is now experiencing angina. The physician has prescribed nitroglycerine PRN for the angina. Which of the following should the RN include in the discharge instructions?

Nitroglycerine and Viagra should be taken at the same time

Viagra is not effective when used in combination with nitroglycerine

Viagra should not be used within 24 hours of taking nitroglycerine

The effect of nitroglycerine is impaired by concurrent use of Viagra