Age: First brought to market in 1998. So 15.

Appearance: Little blue pill.

There's Viagra news? There is indeed.

What's up now? Guess.

The company's performing better? Nope.

Stockholders are experiencing unprecedented growth? Not exactly.

There has been a healthy rise in the share price? Guess again.

This is too hard. I give up. Viagra manufacturer Pfizer is about to lose its patent protection in the UK.

You mean the effects of the patent are wearing off? More or less. The patent expires on 21 June. Rival companies will then be free to sell generic versions of the drug – which is commonly used to treat erectile dysfunction – under its chemical name, sildenafil.

Can't these Pfizer guys just take another one? Another patent? No. Patents don't work like that. Once they're gone, they're gone.

So UK sales are about to flop? Perhaps. Estimates suggest as many as 20 manufacturers plan to unveil generic versions of sildenafil in the next few months, at prices more than 10 times lower than the current rate of around £10 a pill.

And without the patent, Pfizer won't be able to keep it up? Probably not, no. Sildenafil may soon be on shelves for as little as 85p a pill. Which is good news not just for users but for the taxpayer as well. The NHS spent around £40m on Viagra in 2012 and could be set to make major savings if doctors choose to prescribe a cheaper alternative.

How does Pfizer feel about all of this? Embarrassed and powerless? Not entirely. The drug is still making the company around $2bn a year and it plans to stay in on the action here in the UK by launching its own cut-price alternative, Sildenafil Pfizer, when the patent runs out. Plus, it still has another seven years until the patent wears off in America.

So they can keep going at it with US customers until 2020? Pretty much.

Do say: "Don't worry about it. It happens to most enormous pharmaceutical companies."

Don't say: "I just never thought it would happen to an enormous pharmaceutical company like me."