So I take drugs. So what? I am part of a self-medication nation. It’s just that rather than asking my doctor or pharmacist for prescription drugs, I swap them with other people. Nothing illegal; I’m tal king about painkillers, sleeping pills and the odd Viagra (just for kicks). And there are more and more of us dishing out our own drugs to each other. Sharing prescription drugs is as commonplace as swapping books or DVDs. Meet the pharmafriends.

Mary-Rose, 32, is a publishing executive and a single mother of a daughter, aged 7. She regularly gives her friends Coproxamol, a strong painkiller which had been prescribed for her endometriosis, a painful womb condition. Until recently, she also gave her friends Flixonase, an extra-strong nasal spray for her asthma, eczema and hayfever - but it is now available in pharmacies. In return, she gets sleeping pills. No money changes hands. “I don’t have a problem sharing prescription drugs with my friends,” she says. She lives on a leafy North London street where there are no drug dens. All the drugs, locked safely in a drawer in her flat, are obtained legally.

“I get regular prescriptions for my ongoing conditions. My endometriosis means an annual operation and monthly painkillers. Basically, I never throw anything out; you never know when it might come in handy,” she says.

I do the same. My friends and I regularly swap pills. Most of the drugs we are talking about are prescription-only, though some are available illegally online. Ritalin, prescribed for attention deficit hyperactivity disorder, is speed, so if I wanted to speed up I could score some Ritalin from a colleague with ADHD, although I never have. If I want to slow down, I use diazepam, obtained from my mother who is scared of flying. I saved some dihydrocodeine from a nasty dental episode some years ago. They knock you right out. I haven’t given those to anyone yet; they’re very strong. But it’s a different matter when it comes to tranquillisers and painkillers. Why do we do it? Well, we have all become increasingly expert about our health, with the internet an incredible resource for finding out what’s wrong and how to help ourselves. With more and more of us adept at self-diagnosis, self-medicating is the next obvious step. It’s quicker and easier than trying to get an appointment from a GP low on time and sympathy. Pharmafriends are there for you outside surgery hours: they do home visits; they don’t judge; and there are no charges.

Simon, a super-busy, 26-year-old marketing executive, regularly swaps prescription drugs because, he says, he finds it hard to get time off work to see his GP. But it’s not just about doctors. It’s about being fully equipped for our increasingly hectic lives. If I am lying in bed at night stressed about work the next day, I need to get to sleep. I don’t have hours to meditate on my problems and pursue a chemical-free path. I want a sleeping pill. And I want it now.

“I’ve got a career to manage and a child to raise,” says Mary-Rose. “I also want to have a life. I know my body better than my doctor and if I want to take something to get an early night, that’s up to me.”

Richard Vautrey, a Leeds GP and member of the British Medical Association’s GP committee, is aware that this behaviour is increasingly widespread. “It’s not just young people. We often come across patients who borrow medications from friends or relatives and share their own.” But the practice is dangerous, he says (see panel above). “Your medication may be inappropriate for someone else. You might have an undiagnosed allergy or experience dangerous interactions with other drugs. The farther drugs get from the proper source the more diluted, and potentially dangerous, the health message becomes.”

He rejects the argument that people are being driven to drug-swapping by long waits for doctors’ appointments. “You can usually see your doctor the same day. There’s no excuse for not consulting a doctor.”

But even if you see a doctor, some pharma-friends aren’t convinced that they always know best. “I do research to make sure I know the latest treatments for allergies,” says Mary-Rose. “Often I know more than my GP. A girl in my office had eczema that her NHS doctor couldn’t treat and I cured her with an ointment called Protopic that I got from a private doctor. I’ve taken my medications for years. I know they’re safe. I am responsible; I wouldn’t sell them and I give them only to trusted friends.”

We are not talking about potentially lethal cocaine or heroin here. These are rigorously tested, State-supplied medications. The most swapped drugs (painkillers, sleeping pills and Viagra) are among the most commonly prescribed.

I wouldn’t go as far as some American college students apparently do. A recent report in The New England Journal of Medicine claimed that antidepressants are prescribed to half of the students seen at campus health centres. It seems they are faking symptoms for prescriptions that they believe will give them a competitive edge. Another study, published in The Journal of American College Health, claimed that 14 per cent of students at one college reported borrowing or buying prescription stimulants from each other.

I rarely swap something that I, or the person I am swapping with, has not been previously prescribed. Simon doesn’t either. “I don’t do heavy drugs like Prozac,” he says. “Nothing can go really wrong with simple painkillers such as Cocodamol. I’ve swapped with my sister, my best friend and a couple of close work colleagues. We are all careful not to take or swap anything that’s out of date or damaged.”