If you’re keen on taking a little blue pill to help you set on your bedroom eyes, you should be prepared for this literally coming true. It’s well documented that Viagra,  the trade name of a drug called sildenafil, can make you see the world in a shade of blue, besides other more dramatic side effects.

If you’re among the 30 million men who have taken Viagra since it was released in 1998, this information might save you from a panic attack. So, read on to find out more about how the drug affects your vision. They call it the blue pill for a reason…

Smurfs everywhere!

Originally, Viagra was researched as a drug meant to lower blood pressure because it relaxes the walls of the blood vessels, making them larger and decreasing resistance to the flow of blood. So, sildenafil is actually pretty great for those suffering from hypertension as a quick fix in critical situations. Of course, you’ll have to live with a pesky erection for the next 12 hours — but also a blue-tinted vision, among other things.

Many Viagra users report cyanopsia, a form of chromatopsia in which a person has an abnormal color perception — in this case, unexpected blue sensations. That is, everything is seen through a bluish tent.

At a basic level, the drug works its magic by relaxing the penis muscles. It does this by inhibiting an enzyme called phosphodiesterase 5. However, Viagra inadvertently also inhibits phosphodiesterase 6, which is very similar to phosphodiesterase 5, but with far more different and unexpected effects — it overly sensitizes rod cells in the retina.

These rod cells are most effective at picking up blue, so your vision becomes dominated by a blue tint.

Dr. Michael F. Marmor, a professor of ophthalmology at Stanford University in Palo Alto, Ca, says blue vision becomes a more frequent side effect when someone takes high doses or abuses the drug, but it typically fades as the drug wears off. 

“You should probably avoid driving since the blue aura may be distracting,” Marmor says, cautioning you shouldn’t perform other activities when taking Viagra — stick to what it’s meant for.

In some extreme cases, people have reported losing their sense of color vision altogether. Heating engineer John Pettigrew, 58, father of two, took pills bought on the Internet after one year of abstinence.

“I admit I ignored the advice on the packet. I was having too much fun. But I’d give up all the sex in the world to be able to see a red letterbox again. I have been seeing the world in blue for more than a fortnight now and it’s doing my head in. At least I’m a Chelsea fan,” said John, a resident of Brighton, East Sussex.

If you think you can live with blue vision, you might consider hearing about the other side effects. Studies have shown that sildenafil causes hearing loss and harms the sperm, destroying its ability to fertilize an egg.