Pfizer continues to promote conjugated equine estrogen drugs based on flawed, antiquated science



Science has given us medical miracles and technology is light years ahead of what existed when the FDA approved Wyeth’s patent for Premarin, formulated from the urine of pregnant mares, in 1942.

In reflecting back on the years since that fateful event, cutting-edge technology and drug innovations have been pivotal in deepening our understanding of disease as well as ailments that accompany the progression of aging.

Improved diagnostic accuracy though the use of CT scans, magnetic resonance imaging and positron emission tomography, recombinant DNA technology, stem cell research, new drug technology, targeted therapies for cancer, improved antibiotics, the list goes on.

Despite these advances, Pfizer continues to promote their conjugated equine estrogen drugs based on antiquated science – science that has since been proven to be flawed. Bad science if you will.

In fact, the findings of the WHI study was listed as one of the top ten medical advances of the decade in an article published in 2009; “The Top 10 Medical Advances of the Decade: From genome to hormones, doctors pick the top medical advances of the decade.” [1]

Why are these drugs still here 13 years after the fact? Why haven’t the FDA and other drug agencies around the world pulled these from the market?

Time and again the antagonistic effects of conjugated equine estrogens have proven to be potent carcinogens that give rise to a variety of cancers and other life-threatening diseases.

The FDA and other governing bodies such as the European Commission in the EU continue to endorse these drugs as safe therapies for women of menopausal and post-menopausal age despite the unequivocal dire warnings on the packaging cautioning women of substantial risks that should, in any dutiful context, prevent these drugs from being marketed.

And now Pfizer has another patent in Duavee (NA) and Duavive (Europe), actually five patents on this drug – a drug that incorporates the malignant conjugated equine estrogens with the SERM bazedoxifene.

Is this drug really new?

Not really, after all it contains technology from the 1940’s.

Innovative, effective and risk-free?

Hardly – there is scant data to suggest there will be no adverse reaction to the conjugated equine estrogens in the form of insidious cancers or the like.

Pfizer has readily admitted this as evidenced from the warnings on the innocuous little box that contains this venom. But that’s OK because the FDA says so.

Pfizer also has patent exclusivity to market these vile drugs at lucrative profits at least until 2017. [3][4]

More likely well beyond this date as there is no indication that an Abbreviated New Drug Application (ANDA) has been submitted for Duavee to serve as a competitive generic. Besides there is no generic version of conjugated equine estrogens (CEEs) which comprise the drug Premarin.

“Way back in May 1997, FDA ruled in the context of PREMARIN (conjugated estrogens) Tablets, that because PREMARIN ‘is not adequately characterized at this time, the active ingredients of Premarin cannot now be definitively identified,’ and that ‘[u]ntil the active ingredients are sufficiently defined, a synthetic generic version of Premarin cannot be approved.’ Instead, companies have generally pursued approval of 505(b)(2) NDAs – e.g., CENESTIN (synthetic conjugated estrogens,A) Tablets.”


On top of all of this the vast majority of the mares are now in China – the location Wyeth-Pfizer selected because of corporate greed. In a country with little to no animal welfare regulations or laws – a country where certainly the foals and spent mares will go directly to slaughter.

At least in North America some of them are spared the slaughter pipeline – none will have that extravagance in their new home. And how will they be slaughtered? I recoil thinking about it.

I have often asked myself this question: People loathe the practices of ivory, tiger bone, sea tortoise shell, bear bile, shark fin, rhino horn and other abhorrent harvesting practices. What makes the collection of pregnant mare’s urine any different or any less irrational when there are synthetic versions available that do not prey on the innocent?

It has often been said that it is easier to ignore the truth or resist change than face it because it is simply more comfortable and easier to do so. I guess that’s Pfizer’s motto.
[2] See also 1.

• See Premarin Side Effects at
• Learn more at Premstoppers
Donate to Premstoppers »

© The Horse Fund

3 thoughts on “Pfizer continues to promote conjugated equine estrogen drugs based on flawed, antiquated science”

  1. Premarin is the most horrific drug I have ever taken !!! That was 10 years ago !! Why is this drug still being used ?? STOP !! This is also extreme animal abuse !! I almost bled to death because of this HORRIBLE drug !!


  2. I will bet that if the number of prescriptions given to women from the time that this horse pee was put on the market for the treatment of hot flashes to 2015 this would match the number of elderly women living in nursing homes down through the years that developed Alzheimer’s and dementia. I don’t remember of so many cases of dementia when I was growing up as there are now. I don’t remember of anyone in my family that developed the disease nor did I know of anyone that had it. I worked in nursing homes at different times and each time it seemed like there was more cases of it. That is why there are now so many business’s that cater to the care of these people. I’m not counting cases of cancer but just Alzheimer’s and dementia.


  3. I’ve written my senator and secretary of agriculture. They way they treat these horses if horrific.


Leave a Comment

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s