This is an interesting story on several points. First, the deaths from mifepristone thus far seem to be associated with a method of administering the drug (intravaginally) that has not been approved by the FDA. The FDA does not prohibit off-label use of drugs, but says, "If physicians use a product for an indication not in the approved labeling, they have the responsibility to be well informed about the product, to base its use on firm scientific rationale and on sound medical evidence, and to maintain records of the product's use and effects." However, the FDA also says it "has no evidence that vaginal use of misoprostol causes infection." Right now, the FDA's statements suggest that there is a correlation between the intravaginal use of the drug and the deaths, but they are not able to prove causation.
So, what information led prescribers to use the drug intra-vaginally? Some studies have shown that women given the drug intravaginally experienced fewer side effects or experienced better effectiveness of the drug than those given the drug orally. Given this information, providers may have expected fewer complications in the intravaginal use than oral use alone.
Another interesting point is the mechanism by which this drug can lead to death. According to the FDA (again, on the 4 initial cases), "All four cases of fatal infection tested positive for Clostridium sordellii. In addition, FDA tested drug from manufacturing lots of mifepristone and misoprostol and found no contamination with Clostridium sordellii." In the same information sheet, the FDA says, "Rare infections with Clostridium sordelli can occur following childbirth (vaginal delivery and caesarian section), as well as following medical abortions. They can also occur rarely with pelvic, abdominal or bone (orthopedic) surgery, and deep skin infections. The bacteria may also be present in women’s intestinal and rectal areas and cause no symptoms whatsoever, not producing any toxins. This is called 'colonization' and is not known to be a health problem. It is unclear exactly what factors cause the bacteria to produce the toxins in women." Essentially, the FDA is saying that each woman tested positive for the bacteria, infection can occur either with medical abortion, vaginal birth, or c-section, and it's not proven that intravaginal use was the cause. It seems that we need a bit more information on what exactly is going on in these cases. With better understanding of how the toxin is produced and individual risk factors, providers should be able to make better decisions with their patients.
The third point that I've seen little discussion of is how dangerous this drug is compared to surgical abortion or childbirth, or compared to other drugs. The FDA states, "Reports of fatal sepsis in women undergoing medical abortion are very rare (approximately 1 in 100,000)." This table from the 2005 Health, United States report lists the 2002 maternal mortality rate as 7.6 per 100,000 live births. This would suggest that of 100,000 women who either have medical abortion or a live birth, live birth is more deadly to women, although more information is likely needed. Information on mortality rates for other prescription drugs was not readily available, but would be interesting to compare.
One thing I didn't know until I started looking into this is that mifepristone has been looked at as a treatment for endometriosis and several cancers and is currently being investigated for use in other conditions, including whether it improves the outcome of electroconvulsive therapy in patients with major depressive disorder, how it might affect prostate cancer, and effects on uterine leiomyomas. Meanwhile, bills have been introduced in the House (HR1079) and Senate (SB511) to have the FDA's approval of the drug withdrawn.
Some resources:
Technorati Tags: abortion; drug safety; mifepristone; RU-486
MeSH Tags: Clostridium sordelli; Mifepristone
No comments:
Post a Comment