Question

The popular drug Viagra treats erectile dysfunction in males (we will learn this when we do reproduction!). Viagra is a cGMP phosphodiesterase (PDE) inhibitor. While it specifically targets the isoform of cGMP PDE that is present in the male reproductive organs, if taken in high doses, it can affect vision. Which type of vision would Viagra be more likely to affect?

1) light/color vision
2) dark vision

Answer 1

Viagra, a cGMP phosphodiesterase inhibitor, is more likely to affect light/color vision if taken in high doses. Option 1 is answer.

Step-by-step explanation:

Mechanism of Viagra:

Viagra inhibits the phosphodiesterase enzyme responsible for breaking down cyclic guanosine monophosphate (cGMP), a molecule involved in vasodilation. In the male reproductive organs, this leads to increased blood flow, treating erectile dysfunction.

Vision Effects:

Viagra's inhibition of cGMP PDE can also affect the PDE isoform present in the retina, impacting vision. High doses may lead to altered light/color vision, commonly known as "blue vision" or cyanopsia. This occurs due to changes in the perception of the color spectrum.

Option 1 is answer.