MEDICAL MATTERS:There is no magic bullet to cure forgetfulness, writes MUIRIS HOUSTON
TAKING THE contraceptive pill on a regular basis is the key to its success. What to do when you occasionally forget to take it is equally important. And the pill is one of those drugs that is especially sensitive to the effects of an interaction with other medication a woman may be taking while on the pill.
When prescribing the pill for the first time, a doctor has a mental checklist of issues to discuss with the patient. Most of us have a “spiel” that covers these in a logical and hopefully easily understood way. But in recent months that spiel has changed following a reassessment of scientific evidence.
A 2005 study by nurses at the University of Michigan found that two-thirds of women had missed one or more pills during the previous three months. In separate research almost 20 per cent of European women between the ages of 16 and 30 reported missing one or more pills per menstrual cycle. And those who reported missing pills were more than three times as likely to experience an unintended pregnancy as women who took the oral contraceptive consistently.
In the Michigan study the three most common reasons for missing a pill were “away from home”, “forgot” and “no new pack”. Health problems such as nausea and vomiting accounted for only 2.5 per cent of missed pills.
I suspect part of the reason for the unintended pregnancies was the slightly complicated routine that needed to be followed when a pill was missed. But now that has changed for the better.
The UK Faculty of Sexual and Reproductive Healthcare has revised its missed pill advice. Basically, if you miss one pill, there is no need to take extra precautions. If you miss two pills then additional precautions are needed for seven days.
And rather than start a pill on the first day of the menstrual cycle, if it is reasonably certain a woman isn’t pregnant, then the pill can be started on any day of the menstrual cycle, with one caveat: if the contraceptive is started after day five of the cycle then additional precautions are needed for the first seven days.
In the event of vomiting or diarrhoea, the advice is straightforward: if you vomit within two hours of taking the pill, then it is unlikely to be absorbed by the body. Take another pill that day as soon as you feel well enough. However, if you continue to be sick and cannot take a replacement that day, then the missed pill routine kicks in.
If you have very severe diarrhoea that continues for more than 24 hours, this may make the pill less effective. Keep taking your pill at the normal time, but treat each day that you have severe diarrhoea as if you had missed a pill and again follow the missed pill instructions.
Another element of the old “spiel” that has become simpler is what to do when you are prescribed antibiotics while taking the pill.
In the past there were concerns that antibiotics reduced the pill’s effectiveness by interfering with the bacteria in the gut that help to recycle part of the combined pill.
This recycling converts inactive forms of the hormone into active elements essential to ensuring the pill’s effectiveness.
Now the World Health Organisation and other experts have re-examined the research and have concluded the evidence does not support an interaction between the pill and most everyday antibiotics.
However, the liver is the source of another interaction between the pill and other drugs. Drugs used to treat TB, epilepsy and the complementary therapy St John’s Wort may make the pill less effective.
Called enzyme-inducers, these drugs increase the activity of a family of enzymes in the liver called cytochrome P450. In doing so, they directly interfere with the amount of active contraceptive pill circulating around the body.
Meanwhile, there is no magic bullet to cure human forgetfulness. But at least the ground rules for women dealing with forgetting the pill have been reassuringly simplified.
