February 20, 2007
Women's lives are being put at risk because drug companies don't include them in drugs trials. This means potential side-effects are not exposed until the drugs hit the shelves, and by then it's too late, says Dr ANITA HOLDCROFT, a consultant anaesthetist at Imperial College London and Chelsea and Westminster Hospital.
She recently voiced her concerns in the Journal Of The Royal Society Of Medicine.
For too long there has been a dangerous sex divide in the world of medicine. While we talk about the achievements of feminism, there is one significant area where women are still second-class citizens - and it puts thousands of women's lives at risk.
It all comes down to the way new treatments are developed.
Most drugs are tested predominantly on men, and then results are applied to both sexes. But men and women can react very differently to drugs - and side-effects are twice as common in women as in men.
This huge oversight, although claimed to be intended to 'protect' women from potential drug reactions, can end up harming and even killing them.
In the U.S., eight out of ten new drugs were withdrawn from the market in 2005 because of side-effects in women, and while we don't have this information in the UK, it's fair to assume the same is happening here.
Scientists in the U.S. also estimate that tens of thousands of patients every year suffer harm or die from unreliable diagnostic tests for conditions such as heart disease, or because they are given drugs that don't work for them.
A UK Medical Research Council-funded study found that only 16 per cent of people who take part in statins trials are women.
I see the problem at first hand in my job as an anaesthetist. I give many new painkillers to women without evidence that they work for them. This is despite the fact that analgesics is one area where we know men and women react very differently to treatments.
We know women need less morphine than men to achieve the same level of pain relief, for example, but generally women need more pain relief after surgery than men because they recover from anaesthetics more quickly. Yet this knowledge is borne out of experience rather than tried and tested research.
There are also gender differences in irritable bowel syndrome. Women tend to experience more constipation than men, but women often take more drugs to relieve IBS - are these symptoms related to the drugs and side-effects of these drugs, or the condition itself? We don't know, but suspect gender has a role.
America has got much better at testing drugs on women since the U.S. National Institutes of Health issued a guideline in 1994 for the study and evaluation of gender differences in clinical trials.
This ensured that the safety and effectiveness of drugs would be adequately investigated in the full range of patients who would use the drug. Before this, women had been excluded from most studies.
But the fact that so many drugs are still withdrawn once they hit the shelves because of side-effects in women suggests that still not enough women are being included. It's frightening.
I wish we knew exactly how many women attended trials in the UK, but unfortunately this is another black hole - this data is not available, which is further evidence of Ethics Committees and drug companies not thinking it is important to analyse the way the different genders react to drugs when testing them.
We only know the total numbers of both sexes that take part in trials.
The Northwick Park Hospital trial is a classic example of women being excluded. Amid all the furore about the horrific side-effects the men experienced in the trial, no one commented on the fact that only men were involved. Women might have reacted completely differently to the drug.
So why are pharmaceutical companies so bad at involving women in clinical trials? The simple answer is that it costs more.
This is because when women are included, they throw up different results from men - which is precisely the reason we need them - and this means the trials last longer.
There are also more hormonal fluctuations to be taken into account with women. And drug companies worry about women suing them if things go wrong and they react badly to the drugs.
If only men are tested they will get more positive, and, crucially, faster results. Drug companies want to get their products on the market as quickly as possible and this is the best way to do it.
But it's short-sighted - they already spend millions developing drugs, and involving women in more trials would be money well spent, especially if not doing it means their drugs are dumped and all that money is wasted, as we know is happening in America.
A big issue in testing drugs on women is the risk that they might be pregnant or fall pregnant during a trial, and the drugs might affect the baby.
But this can be avoided if women of reproductive age are on oral contraception and it should not be used as an excuse for not including them.
Another impediment is that it tends to be harder for women to spare the time to attend trials because of child-care issues.
The UK Research Ethics Committee, a Department of Health body which has to approve clinical trials before they go ahead, should remove such barriers to women being included in clinical trials (without, obviously, putting their health at risk) and drug companies should be made responsible for making it easier for women to attend.
It's not just women who are excluded: many drugs are not researched in children either - they just get a reduced dose of the adult drug - something which is of great concern to paediatric specialists.
But new regulations state that clinicians must report any problems when drugs are administered, which is giving us a lot of much-needed data. The same should apply to gender effects.
The National Institute for Clinical Excellence has a responsibility here, too. It has no gender-based guidelines for pain relief or any other drug treatments, which is a grave oversight.
Not only do we need more research into drug treatments, we need basic scientific research to learn more about the physical differences between men and women - right down to the composition of their cells, which affect what chemicals the cells produce and the way different drugs react to them.
The failure to do this research is also putting women's lives at risk. Coronary artery disease is a good example. Much more money is spent on researching this condition in men, yet, of the women who are at risk from heart disease, more die.
Doctors often misdiagnose heart attacks in women because the symptoms are different from those men experience and not enough is known about them.
In women the pain is not restricted to the chest - symptoms can include nausea, breathlessness and an upset stomach and medics often assume they are suffering from gastro-intestinal problems rather than chest problems. This mistake can be life-threatening.
Medical students are taught about these differences, but mistakes are still being made. Also, because women tend to report pain more often than men, doctors are often guilty of not taking their complaints as seriously.
About 50 years ago, if women had headaches, they would be advised to have hysterectomies - but men would never have been encouraged to have their manhood removed in the same circumstances. Fortunately, this horrendous sexism no longer exists.
Similarly, women in pain were often diagnosed as being hysterical in the Fifties, and no one would make that diagnosis now.
We have got much better at understanding the differences between men and women, but we still have a long way to go if we are to give all our patients, whatever their gender, the best treatment available.