Acne drug may harm pregnancy
by Honor Whiteman
It is well established that the acne medication isotretinoin can
cause severe harm to a developing foetus, which is why pregnancy
prevention guidelines are in place for its use. A new study, however,
suggests many women are not adhering to such guidelines.
Up to half of Canadian women using isotretinoin do not adhere to the
current pregnancy prevention guidelines, suggests a new study.
Published in CMAJ, the study suggests up to 50 percent of women in
Canada taking isotretinoin do not comply with the country's current
guidelines for use of the drug, resulting in birth defects, miscarriages
and pregnancy terminations.
Isotretinoin
belongs to a class of drugs known as retinoids, and it is prescribed for
severe recalcitrant nodular acne that has not responded to other
treatments. The drug works by reducing the production of certain
compounds that are known to contribute to acne.
Isotretinoin is known to increase the risk for pregnancy loss, birth
defects - including craniofacial and heart defects - and death shortly
after birth. As such, the US Food and Drug Administration (FDA) launched
the iPledge program, which aims to reduce fetal exposure to isotretinoin.
The FDA require that only prescribers and pharmacists registered to
the program are permitted to prescribe and dispense the drug.
Additionally, all patients must be registered to iPledge and complete an
informed consent form before using isotretinoin. Women of reproductive
age must have two negative pregnancy tests before they can be prescribed
isotretinoin under the iPledge program, as well as undertake a pregnancy
test each month of drug use and use two forms of contraception, which
should be recorded by their healthcare provider on a monthly basis.
Canadian guidelines
While Canada - where the new study was conducted - has not adopted a
program that is the exact equivalent to iPledge, there is a program in
place that "requires informed written consent, two pregnancy tests with
negative results before starting isotretinoin and two reliable forms of
contraception during treatment," according to the authors.
But is this program effective? This is what lead author Dr. David
Henry, senior scientist at the Institute for Clinical Evaluative
Sciences (ICES), Canada, set out to investigate.
He and his team analyzed the health records for 59,271 women aged
12-48 years who were taking isotretinoin between 1996 and 2011. The
women were from four provinces of Canada: British Columbia,
Saskatchewan, Manitoba and Ontario.
During the 15-year study period, the researchers identified 1,473
pregnancies among the women, of which 118 (8%) resulted in live births.
A total of 11 (9%) of these live births involved congenital
abnormalities, according to the authors.
Medically induced abortion ended 1,041 of the pregnancies, while 290
were spontaneous losses.
The team identified a pregnancy rate of around four to six
pregnancies per 1,000 women who used isotretinoin for a 3-month period.
25-30 percent of women did not fill birth control prescriptions
Overall, the researchers found that between 30-50 percent of women
using isotretinoin did not adhere to current guidelines.
Only around 25-30 percent of women using isotretinoin filled birth
control prescriptions while using the drug, despite guidelines stating
that they must use at least two reliable forms of contraception during
this time. According to the researchers, their findings indicate a poor
performance of the pregnancy prevention guidelines for isotretinoin use.
"Poor adherence with the Canadian pregnancy prevention guidelines
means that Canada, inadvertently, is using pregnancy termination rather
than pregnancy prevention to manage fetal risk from isotretinoin," says
Dr. Henry.
The team says the findings support previous research suggesting that
inadequate use of contraception is a leading reason for pregnancy during
isotretinoin use.
"US studies have shown that the impact of the iPledge program also
appears to have been modest in terms of increased uptake of oral
contraceptives and reduced numbers of exposed pregnancies," say the
authors, adding:
"It is clear from this experience and from studies in Europe that
modifying contraceptive behavior in this setting is difficult.
Nevertheless, medical practitioners and patients must be constantly
reminded of the risks of isotretinoin to the fetus and must adhere to
the policy that mandates effective contraceptive measures."
-MNT
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