‘Many drugs not tested on women’Comment on this story
London - For two years, 37-year-old Janice Price (not her real name) has struggled with a dilemma. She wants to start a family with her husband, Paul, but charity worker Janice has suffered from depression for a decade and is worried about evidence linking the side-effects of depression drugs with harm to mother and baby.
Recent studies of mothers taking anti-depressants indicate they may have a significantly higher risk of the potentially lethal blood-pressure condition, pre-eclampsia, and of going into premature labour.
Their babies may suffer problems with their IQ and growth, other reports suggest. And Harvard researchers recently linked the drugs to a much greater risk of miscarriage and autism, too.
Janice, who lives in Brighton, West Sussex, says she dare not stop taking anti-depressants, because when she has tried in the past she has plummeted into the depths of psychiatric illness. “Trying to get pregnant while on these drugs, with all the reported risks, just seems too frightening,” she says. “I’d like some reassurance.”
No one can tell Janice the real risks, because the drugs were not tested for safety on pregnant women before being approved for use.
Fears over the safety of antidepressants for pregnant women have been raised only after the drugs were approved for use - and only when researchers around the world noticed abnormal patterns of illness among mothers and babies, and then found unusually high proportions of the women had taken anti-depressants while pregnant.
Retrospective research can raise questions about a drug’s safety, but it does not provide the same level of sound scientific proof as clinical trials of a drug before it is approved. In properly controlled clinical trials, scientists can account for variables - such as women’s weight, diet, lifestyle, pre-existing health and any other drugs they take - so they can pin harmful side-effects on to the treatment.
But many pills most commonly used daily by women - such as painkillers and heart drugs - were never tested on females, pregnant or otherwise, before being put on the market.
Instead, they were tested for safety on men - because males don’t have fluctuating monthly hormonal cycles that may alter the drug’s actions, making them simpler test subjects. It avoids complicating trial results, which could affect getting that drug on to the market quickly.
Mounting evidence shows women’s bodies can react far differently than men’s to the same widely prescribed drugs. At least one million people a year in Britain are admitted to hospital for treatment after severe adverse reactions to prescription medicines.
Most recently a Dutch study found that women were four times more likely than men to suffer side effects to diuretics - commonly prescribed blood pressure pills.
These range from nausea and confusion to coma and even death, but this study is the first to suggest women face a much greater danger.
Researchers at Erasmus Medical Centre in Rotterdam analysed 7,000 patients admitted to hospital after reacting to their medicines.
They studied the types of drugs involved and the ratio between the sexes. The biggest difference was in commonly used cardiovascular drugs, which accounted for one in three admissions. Researchers found that with one of these drugs - diuretics - women are four times more likely to experience side-effects.
The most common reaction was a sharp drop in sodium levels, caused when too much gets flushed out in water through the kidneys.
The Dutch study supports earlier research. In 2001, New Zealand scientists found women were 70 percent more likely to suffer reactions to drugs for skin conditions.
With the commonly used blood-thinning drug, warfarin, the problems with excess bleeding are significantly more common in women, while anti-histamines for allergies are another case in point, says Dr Peter Dewland, an independent pharmaceutical consultant.
“Antihistamines, particularly the older types, are processed much more slowly in women, so tend to make women feel more sleepy than men.
“Also, the newer classes of antipsychotic drugs - used for mental problems such as schizophrenia, bipolar disorder, severe anxiety and depression - have a significantly increased chance of side-effects in women. They are known to cause metabolic syndrome (increased body weight and diabetic problems), and dangerous heartbeat irregularities.”
“Women are about twice as likely to suffer side-effects from prescribed drugs as men,” says Dr Anita Holdcroft, a consultant anaesthetist at Imperial College London.
This may be because the drugs are not tested on women or because of different female biology: lack of research means we can’t be sure.
Dr Holdcroft arrived at his figure by studying the latest official figures on reported side-effects, released earlier this year by the official drugs watchdog, the Medicines and Healthcare Products Regulatory Agency (MHRA).
Harmful side-effects are reported to the agency by doctors and patients. Of course, men also react badly to drugs. But the fact that they report only half as many bad side-effects indicates women’s problems differ widely in their scale and nature.
It may also be that women perceive side-effects differently than men - they may be more alert to their bodies’ responses - but again, this has not been investigated properly.
Even with the most common drugs, such as non-steroidal anti-inflammatory painkillers, “we do not know how they affect women differently, even though these drugs are potentially dangerous,” says Dr Holdcroft, who is a member of the Medical Women’s Foundation, the largest organisation of women doctors in the UK. “For example, we know from studies that the effects can be intensified by the use of contraceptive pills.” But often the reasons remain unknown.
“The basic science of pain research has involved only 8percent females. In tests of anti-inflammatory drugs, 90 percent have no data about sex differences,” says Dr Holdcroft.
There are no legal barriers to women participating in clinical trials, but practices in the pharmaceutical industry means they are often excluded.
This is particularly true when drugs are safety-tested in humans for the first time, with dosages gradually increased. “Women are more variable as research subjects. They have hormonal cycles and child-bearing, and their responses to drugs may change again after the menopause,” says Dr Holdcroft.
Drug researchers often avoid testing such variations because they complicate results - which is not what drug companies want.
As the first stage of clinical trials are aimed mainly at persuading regulators that a medicine is safe and effective enough to be licensed for profitable commercial use, drug company researchers focus on the more physically stable male sex.
A spokesman for the drug-makers’ representative organisation, the Association of the British Pharmaceutical Industry, says women are not excluded from clinical trials “unless it would be unethical to include them, as in the case of a male-specific disease such as prostate cancer,” he says.
“Careful consideration is given to whether a woman is of child-bearing potential or menopausal, as these would be specified in the inclusion and exclusion criteria for a trial. To restrict recruitment into clinical trials for a gender reason, without rationale, does not happen.”
However, independent pharmaceutical consultant Dr Dewland, who has been involved in running more than 100 human drug trials, says nearly all these studies have been on men - at the drug companies’ request.
“Because the effect on fertility on drug trial results has not been adequately studied, we tend to use males. Even if we find a drug affects male and female animals differently in lab tests, we may not look hard for those problems when we test the drug on humans,” he says.
“I was even asked to use men in a safety trial for a drug for helping women in labour. The pharmaceutical-industry client took some persuading to use women.”
But proper trials of all drugs should involve women, says Dr Dewland - women are generally smaller and weigh less than men, so may require different dosages or smaller pills.
And women’s bodies can absorb drugs differently and react to them in different ways.
“Often, drugs may bind differently to chemical receptors in women’s bodies,” he says. Chemical receptors are the points in the body that react with the drug and absorb it.
“Women also tend to have a higher proportion of body fat than men - and many drugs bond to fat molecules.” This means that a woman’s body may absorb a higher amount of a drug than a man, even when given the same dose.
They are likely to store more lipophilic medications, which dissolve better in fat than water, before releasing them into the bloodstream.
Even if they take the same dose of a lipophilic medicine as a man, women’s blood levels may be much higher, potentially raising side effect risks.
Women’s kidneys work more slowly than men’s, so chemicals stay in their systems longer. This may lead to excessive drug levels and increased risk of reactions.
Women’s stomachs are also less acidic than men’s, which may change the nature of drug reactions.
Serious ethical dilemmas must be tackled if women - particularly in pregnancy - are to be represented in drug trials.
Virginia Watson, president of the National Association of Women Pharmacists, says: “Women take medicine while pregnant, so the drugs are being used in an unauthorised way, because their effects haven’t been clinically tested.”
It would mean intentionally exposing mothers and babies to a new, possibly dangerous drug in a controlled trial with medical monitoring and support. How many pregnant women would go on a drug trial?
The alternative is to give the drug to millions of pregnant women, then try to monitor what happens.
The meeting of the Royal Pharmaceutical Society last year agreed to press the MHRA to ensure women are represented in all drug trials, and that information on differences in women’s and men’s reactions to drugs are studied and published.
In the meantime, women such as Janice Price will be worried.
“I’d love to try for a baby, but I can’t stop my antidepressants,” she says. “Without information about the side-effects, I’m stuck.” - Daily Mail
* Additional reporting: PAT HAGAN.