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Beta-agonists and atrial fibrillation: Say what?

If I was comfortable administering a beta-blocker to an unborn 36-week-old infant, do you really think I worry about eating any meat product that saw a beta-agonist in its feed when it was alive?

I was reading an on-line food safety journal recently that was talking about animal agriculture’s concern that the proposed farm bill currently being discussed does not go far enough in funding to protect animal health from diseases such as foot and mouth disease and avian influenza that could destroy export markets.

I thought it was a fair article, but as often happens the comment section headed south of rational.

A writer named “Sue” asked if there was a bill banning unnecessary antibiotics and all beta-agonists in animals raised for food. Sue said we all know what is happening because of antibiotic misuse but not enough studies have been done in humans to know what side effects beta-agonists may have in people.

She postulated that maybe they are the cause of our atrial fibrillation epidemic (her words, not mind) and then asks if the company selling antibiotics also sells anticoagulants used to prevent complications from atrial fibrillation.

The only credit I will give Sue for intelligent thinking is that “she” knows people with atrial fibrillation can form blood clots from stagnant blood in the atrial chamber that can be fatal, and the treatment includes blood thinners.

I will get to what may be news to Sue about beta-agonists and humans and news you can use to defend the use of beta-agonists in just a bit, but first a quick review of beta-agonist use in animals.

We all know that at this time there is only one beta-agonist being sold in the U.S., and that is ractopamine. It is sold under the trade name Paylean for hogs and Optiflexx for cattle and turkeys.

We also know that the company currently selling the products is Elanco, located in Greenfield, Ind. Elanco is the animal health branch of Eli Lilly Pharmaceuticals, a very large company located 50 miles east of Greenfield in Indianapolis, Ind.

I do not know but would guess Eli Lilly has a few products used in atrial fibrillation.

“Sue” said after she raised the question of the possibility the same company making beta-agonists was making blood thinners, “Now there’s a business model.”

What “Sue” may not know is that Elanco will probably go its separate way from Eli Lilly very soon through an IPO.

We all know the use is to make a leaner meat and promote growth in the animals’ last days.

We know use is limited to 42 days and no withdrawal period is mandated because of the very short half-life of four hours. Use is limited to the last 42 days of life because it is ineffective in young animals, and it loses effectiveness somewhere around 42 days of use.

We also know that the Food & Drug Administration has established 50 parts per billion as the maximum residue limit (MRL) and that in 2012 the Codex Alimentarius Commission set ten parts per billion as the MRL.

We are well aware that the Food Safety & Inspection Service at USDA regularly tests meat, livers and kidneys for residue in food animals at the slaughter facilities, and that testing includes beta-agonist residues.

The Red Book is FSIS’s bible on residue testing. If one googles it one will soon learn that each year there may be one or two non-violative samples test positive, but almost never do they find beta-agonist residues in violation of FDA’s MRL.

The testing also includes looking for beta-agonists that are not legal in the U.S. but have sometimes been found in other country’s samples such as clembuterol and salbuterol that have much longer half-lives, meaning a trip to market may not be enough time to clear the meat and organs of residues high enough to potentially be toxic to humans.

So, now to what Sue and some readers may not know about beta-agonists and humans.

Sue said not enough testing has been done.

Well, Sue, health care providers have been prescribing beta-agonist for use in human medicine for probably over 45 years now. Forty-five years ago I graduated from medical school and we were using them then.

Those are millions of patients that have had beta-agonists enter their blood stream via inhalers, subcutaneous injections, intravenous infusions and pills.

The recipients range from the unborn child to the nursing home patient.

I think, in fact I know, we have a pretty good idea of the effects of beta-agonists in humans - a little faster heart rate, maybe a rise in blood pressure, maybe even a bit of reddened skin.

But atrial fibrillation would really be a rare result, and that would be most likely from a straight injection into the blood stream of the pure stuff, and not a pork chop being consumed with negligible, if any, beta-agonist residues.

Many of the readers may have a child with asthma, or maybe even suffer from that restrictive airway disease themselves. If so, they know albuterol is a quick acting beta-agonist usually administered by a hand-held inhaler during an acute asthma attack under the trade name of Proventil. Another example would be metaproterenal (Alupent). Clembuterol and salbuterol may be prescribed as longer acting inhaled drugs to prevent attacks.

What many do not know, certainly Sue must not, is that a beta-agonist called terbutaline (Brethine) has been given by the IV route for decades to stop premature labor. It is not even licensed for that use but is so safe and so successful that physicians have used it for decades.

It seems some women in premature labor had asthma attacks and used their rescue inhalers like albuterol and voila, their labor stopped, and a new use for beta-agonists was discovered by pure accident.

Terbutaline is used for 72 hours so other medications can be administered to help the premie’s lungs mature and help avoid complications of premature birth. It is not used long term nor to prevent premature labor; it does have potential side effects.

But even with the risk of a fast heartbeat, it by far beats the old alcohol drips that were once used to stop premature labor and the newborn will show no side effects from the beta-agonist that it was exposed to. 

Now I do think my pork chops and steaks might be bigger than I need to consume, but if I was comfortable administering a beta-blocker to an unborn 36-week-old infant, do you really think I worry about eating any meat product that saw a beta-agonist in its feed when it was alive?

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