Oh my. Now another American desiccated thyroid (NDT) brand recall?
Earlier this year, Acella’s NP thyroid was found to be superpotent (over 110% on the T3 content), and they issued a voluntary recall.
Now, as of August 25, 2020, Nature-Throid and/or WP-Thyroid are sub-potent, so their manufacturer RLC Labs is issuing a voluntary recall.
“RLC Labs, Inc. is dedicated to the health and safety of our hypothyroid community.
As our number one priority, we want to ensure that you are aware of our decision to issue a recall of all unexpired lots of Nature-Throid® (Thyroid USP Tablets) and WP Thyroid® (Thyroid USP Tablets) that are currently in commercial distribution.
This recall has been initiated because testing found that certain lots of these products may be sub-potent (i.e. contain less than 90% of the labeled amount of liothyronine or levothryroxine).
We have voluntarily decided to recall all unexpired lots in the marketplace to ensure that patients only receive product that meets our high quality standards.
As of this release, we have not been notified of any adverse reactions from patients related to this recall of Nature-Throid® and/or WP Thyroid®.
We are currently working in tandem with the FDA to ensure the quality and safety of our products.”
See the original on the RLC website.
In case they update the notice, a copy is also publicly archived on Archive.org here.
Tell us how much.
They say that their batches were found to be less potent than the FDA permitted variance, <90% on T4 and/or T3, but they won’t say exactly.
UPDATE SEP 6, 2020: “The products are being recalled because testing of samples from six (6) lots by the U.S. Food and Drug Administration found the samples to be sub potent. The product may have as low as 87% of the labeled amount of Liothyronine (T3) or Levothyroxine(T4).” (FDA notice ) We still do not know whether it is the T3 or the T4 and which hormone (s) it was in the Nature Throid and the WPThyroid.
In the Acella NP thyroid recall, we were told exactly how much and which hormone was superpotent, so this recall of RLC labs’ Nature-Throid/WP-throid is rather more vague.
Not only that, it is unclear whether Nature-Throid and WP-thyroid are identical in the degree and type of subpotency. Maybe T4 was exactly 87% potency on both brands’ T4, or both brands’ T3, who knows:
- Reference: 100% potency T4 (38 mcg per 65 mg tablet), 100% potency T3 (9 mcg per 60 mg tablet) according to prescriber’s information.
- Option 1: Subpotent 87% in T4, meanwhile any shifts can happen within the allowed 90-110% potency in T3 and they don’t have to tell anyone.
- Option 2: Subpotent 87% in T3, Anywhere within allowed 90-110% potency in T4
- Option 3: Subpotent 87% in both T3 and T4.
We cannot assume that potency went down from 90% to 87% between lots, when the variability the FDA permits without any recall or notice is 90-110% of the stated potency.
- The best case scenario was that you were taking a lower-potency batch at 90%, and you had your doses adjusted and were fine. Then you went from 90 to 87% potency on one of the hormones. That’s only a 3.4% loss in potency.
- In the worst case scenario, you could have been dosed on higher-potency batch at 110% and found your optimal level. And then suddenly whooosh! You’re down at dosing 87% — Therefore, the maximum difference is 26% — you’re losing a quarter of your daily dose of T4 or T3! You’d notice. You’d have to increase your dose!
It makes a difference whether it’s the T3 or the T4 that is subpotent, because each of us converts T4 hormone at different rates. Some of us are poor converters and rely on the T3 content to boost our FT3 levels so we have more active hormone to bind with our receptors.
I’d get my replacement ASAP if I were taking it.
2020/09/10: This was my first reaction when seeing the original notice, prior to the FDA risk statement being published: Interestingly, RLC Labs first notice didn’t load their recall notice with cautions about horrors in pregnancy outcomes (as Acella’s notice did). However, an underdose from sub-potency to both or the T4 content is far more a risk to pregnancy than an overdose due to superpotency of T3 alone. So, in the US regulatory context, a thyroid medication’s T3 superpotency hits the panic button, while a T3 and/or T4 subpotency that could lead to underdose? Underdose? Shrug. Meh. Let them eat more donuts and coffee. Oh wait. But coffee can reduce absorption of T4 hormone from the gut (Benvega et al, 2008).
But now we have more info about risk, not just a shrug!! …
The FDA risk statement: No longer a shrug.
Risk Section added Sept. 10, 2020
Let’s digest what the FDA announcement says about risks in this recall:
Risk Statement: Patients being treated for hypothyroidism (underactive thyroid), who receive sub potent Nature-Throid® or WP Thyroid®, may experience signs and symptoms of hypothyroidism (underactive thyroid) which may include, fatigue, increased sensitivity to cold, constipation, dry skin, puffy face, hair loss, slow heart rate, depression, swelling of the thyroid gland and/or unexplained weight gain or difficulty losing weight.
There is reasonable risk of serious injury in newborn infants or pregnant women with hypothyroidism including early miscarriage, fetal hyperthyroidism, and/or impairments to fetal neural and skeletal development.
In elderly patients and patients with underlying cardiac disease toxic cardiac manifestations of hyperthyroidism may occur, such as cardiac pain, palpitations or cardiac arrhythmia.
RLC Labs, Inc. has not received any reports of adverse events related to this recall.
On the symptoms of hypothyroidism, we can be thankful for their inclusion of such a detailed list. It is rare to see people care about listing the symptoms of hair loss and weight gain, two things that can be incredibly damaging to our identity and our social lives.
I’m not sure why they mentioned “fetal hyperthyroidism” and “cardiac manifestations of hyperthyroidism” near the end, because this is a potency DEcrease not an INcrease. It looks like filler text someone plunked in without thinking clearly!
Other risks not mentioned?
Symptoms, maternal risks, and cardiovascular risks. These are stereotypical top 3 things to mention. They have to be covered.
But the simple fact is that if they listed all the risks to all the organs and tissues affected by thyroid hormone levels, they would have a list as long as your leg.
There is no disease or disorder in the body that is immune to the effects of a severe reduction in thyroid hormone receptor signalling. Thyroid hormone is just that essential to everything functioning well.
If you have another autoimmune disease, skin disorder or kidney or liver dysfunction, your symptoms and overall health could get worse when you are hypothyroid.
But woe unto the people who are just coming out of surgery, or fighting for their lives in hospital intensive care, or struggling in the final stages of cancer or a neurological disease. You can’t risk being hypothyroid without adequate T3 supply for recovery if you’re in Nonthyroidal Illness.
Click to read more about risk to thyroid patients being hypothyroid during nonthyroidal illness
We should be very thankful to them for noticing that risk to fetal life is real. To some people on the borderline of hypothyroidism, a small difference is enough to push them under.
The risk here is very present with REDUCED potency in the T4 portion of desiccated thyroid (NDT). Some women on NDT therapy are superconverters and have a very low FT4 level, hovering near the bottom end of reference, while their FT3 is much higher in range and compensates for the lower FT4.
Click to read more about pregnancy risks with a lower FT4
About heart rate / arrhythmias.
Yes, having hypothyroidism will overall slow the heart rate down (bradycardia). The risk with bradycardia can happen when your heart rate goes down naturally at night, especially if you already have sleep apnea. (Read about bradycardia in this US News & World Report article.)
But there are risks beyond slow heart rate in hypothyroidism that many doctors are not aware of:
- Hypothyroidism (especially low T3) can also cause intermittent spikes in heart rate.
- Low T3 can also cause heart rhythm problems like atrial fibrillation.
Click to read more about cardiovascular risks in hypothyroidism (underdose, poor T4-T3 conversion)
Strange rules about Narrow Therapeutic Index medications
So, back to the topic of potency variability.
Why are thyroid medications permitted to vary so much in potency that they can fall below 90%?
However, drugs containing Liothyronine LT3, which provide T3, the more active hormone we metabolize from T4, are not (yet) considered NTI drugs.
Just like all other non-NTI pharma, therefore, desiccated thyroid medications like RLC labs’ Nature Throid, WP-Throid, and even synthetic Cytomel (T3) can vary 20% from pill to pill, or batch to batch, as long as they stay within 90-110% of the stated dose.
It is completely illogical that the FDA says the less active hormone T4 has a narrower therapeutic index than T3. It’s because synthetic levothyroxine gets more attention.
Apparently the levothyroxine provided by desiccated thyroid preparations is not held to the narrower 95-105%.
Very strange. Very illogical. But that’s the way the policies are right now.
Relevant NDT recall posts:
See our extensive 2-part post that went into the background, history and regulatory context of the Acella recall and examined how much much their superpotency could have mattered to our health.