Managing hypothyroidism often seems straightforward—but the details can make all the difference.
In this episode, Rachel Cole, PharmD, shares actionable pearls for pharmacy teams, such as how to handle levothyroxine product switches, when to monitor TSH, and tips for counseling patients on adherence. Plus, we’ll tackle common myths, explore safety concerns with desiccated thyroid extract (DTE), and review FDA’s recent alert.
Get clear answers, practical counseling tips, and monitoring strategies you can use today.
This is an excerpt from our November 2025 Pharmacy Essential Updates continuing education webinar series.
CE Information:
TRC Healthcare offers CE credit for this podcast for pharmacist subscribers at our platinum level or higher and pharmacy technician subscribers. Log in to your Pharmacist’s Letter or Pharmacy Technician’s Letter account and look for the title of this podcast in the list of available CE courses. None of the speakers have anything to disclose.
Clinical Resources from Pharmacist’s Letter, Pharmacy Technician’s Letter, and Prescriber Insights:
- Article: Put Concerns About Thyroid Meds in Perspective
- Chart: Levothyroxine Absorption: The Effect of Food and Drugs
Don’t miss out! Subscribe today to stay ahead with trusted insights and tools.
Use code cc1026b at checkout for 10% off a new or upgraded subscription.
🎓 Are you a student? Great news—students can access a free version of Pharmacist’s Letter.
📣 New Podcast!📣
🌱Natural Medicines: Evidence in Practice
Evidence, not hype. Concise, clinician‑ready guidance on natural medicines and integrative care. Episode 1: GLP‑1s & Nutrition is live now!
Email us: [email protected].
The content of this podcast is not intended to be a substitute for professional medical advice, diagnosis, or treatment.
Find the show on YouTube by searching for ‘TRC Healthcare’ or clicking here.
Learn more about our product offerings at trchealthcare.com.
Click here to listen to all podcast episodes.
Listen Now:
Transcript:
This transcript is automatically generated.
00:00:04 Narrator
Welcome to Clinical Capsules from TRC Healthcare, your trusted source for practical, evidence-based updates.
00:00:10 Narrator
On this episode, Clinical Pharmacist Rachel Cole explores common myths and real-world challenges in hypothyroidism care.
00:00:18 Narrator
She discusses product switching, adherence tips for levothyroxine, and safety considerations for desiccated thyroid extract in an excerpt from our popular Pharmacy Essential Updates webinar series.
00:00:30 Narrator
This podcast offers Continuing Education credit for pharmacists and pharmacy technicians. Please log in to your Pharmacist’s Letter or Pharmacy Technician’s Letter account and look for the title of this podcast in the list of available CE courses.
00:00:42 Narrator
None of the speakers have anything to disclose.
00:00:45 Narrator
Catch new episodes of Clinical Capsules every 2nd and 4th Tuesday—bringing concise, actionable insights from TRC experts straight to your ears.
00:00:54 Narrator
Let’s dive in…
00:01:01 Rachel Cole
Our article says questions will come up about the safety of desiccated thyroid extract, or DTE, due to FDA’s recent alert, and we’ll talk about how this may affect patients and prescribers as we walk through a general overview of hypothyroidism.
00:01:19 Rachel Cole
Before we dive in, let’s briefly review thyroid hormone and its function, and what happens in hypothyroidism, which will help us better understand the concerns we’ll touch on later.
00:01:31 Rachel Cole
Thyroid hormones help regulate metabolism and growth and development, so they affect practically every organ in the body.
00:01:39 Rachel Cole
Thyroid-stimulating hormone, or TSH, is secreted by the pituitary gland and stimulates the thyroid gland to make and release our thyroid hormones, T4 and T3.
00:01:53 Rachel Cole
T4 is the main thyroid hormone that’s secreted by the thyroid.
00:01:57 Rachel Cole
But T4 actually does not have much activity on its own.
00:02:01 Rachel Cole
Instead, it’s converted into T3 throughout the body.
00:02:05 Rachel Cole
And then that T3 that’s either released from the thyroid or converted from T4 is actually the active hormone responsible for the physiological effects.
00:02:16 Rachel Cole
And then the levels of T3 and T4 in the blood create a kind of feedback loop and that regulates how much TSH is made. So, it’s really a cycle.
00:02:27 Rachel Cole
So if a patient has hypothyroidism, their thyroid gland is underactive for one reason or another, and the patient won’t make enough T3 and T4.
00:02:38 Rachel Cole
And with this decrease in thyroid hormones, many of the body’s functions slow down.
00:02:43 Rachel Cole
So medications, such as levothyroxine, are used to help replace the body’s thyroid hormones.
00:02:51 Rachel Cole
Patients with hypothyroidism can experience symptoms such as fatigue, constipation, cramps, and dry skin, and many times a thyroid-stimulating hormone, or TSH, level can be taken to help evaluate a patient’s thyroid function.
00:03:07 Rachel Cole
And that makes sense when you think about that feedback loop we just talked about.
00:03:11 Rachel Cole
If a patient has high TSH levels, that means the body is sensing that there’s too little thyroid hormone in the blood, and it’s trying to make more.
00:03:22 Rachel Cole
In general, once diagnosed with hypothyroidism, a patient will have their TSH level measured about 6 to 8 weeks after starting therapy, and then the dose of their medication can be adjusted based on those TSH levels.
00:03:37 Rachel Cole
Once the med dose and TSH levels are stable, TSH can be checked again after about six months and then just yearly thereafter.
00:03:47 Rachel Cole
Now when it comes to treating hypothyroidism, we definitely see levothyroxine used the most.
00:03:53 Rachel Cole
It’s synthetic T4, identical to the T4 made by our thyroid.
00:03:59 Rachel Cole
And levothyroxine is then converted by the body to T3, the active hormone.
00:04:05 Rachel Cole
Now another treatment option is liothyronine or synthetic T3, and then the desiccated thyroid extracts, brands like Armor Thyroid or NP Thyroid, come from dried thyroid glands of animals, typically pigs, and have a mix of T3 and T4, plus a mix of other substances secreted by the thyroid gland.
00:04:28 Rachel Cole
And even though there are several options we can use for hypothyroidism, we can continue to think of levothyroxine as the drug of choice.
00:04:37 Rachel Cole
And that’s partly because it has the best evidence of efficacy, it’s well-tolerated, it has just once-daily dosing because of its long half-life, and it’s low cost.
00:04:48 Rachel Cole
And the abundance of dosing options allowing a fine-tuning of thyroid management, while desiccated thyroid doesn’t have this benefit.
00:04:56 Rachel Cole
So we can continue to recommend levothyroxine first line.
00:05:00 Rachel Cole
But one issue that sometimes comes up with levothyroxine is the question about whether it’s okay to switch levothyroxine products.
00:05:09 Rachel Cole
We know this might be necessary, especially if we end up with different levothyroxine brands in our pharmacy from what the patient is taking.
00:05:16 Rachel Cole
Even though many brand and generic levothyroxine products are AB rated or considered equivalent by FDA, some experts still debate whether it’s okay to switch.
00:05:26 Rachel Cole
But despite these concerns, generally speaking, yes, it’s okay to switch levothyroxine products.
00:05:32 Rachel Cole
If there’s a difference in absorption among bioequivalent products, it’s likely very small.
00:05:38 Rachel Cole
Of course, follow your state laws and pharmacy policies if a switch is necessary, and inform your patients about the switch, and put on a new generic auxiliary label if needed.
00:05:50 Rachel Cole
And if there are concerns, you can let patients know that TSH levels can be checked about 6 to 8 weeks after a switch.
00:05:57 Rachel Cole
Also reassure patients that one product isn’t better than another.
00:06:01 Rachel Cole
So another common question that comes up with levothyroxine is does levothyroxine have to be taken on an empty stomach?
00:06:10 Rachel Cole
This seems to be a myth that continues to lead to unnecessary confusion and hardship for patients, since levothyroxine does not necessarily need to be taken on an empty stomach.
00:06:21 Rachel Cole
Now, taking levothyroxine on an empty stomach is ideal because we know that absorption is higher on an empty stomach.
00:06:29 Rachel Cole
For example, taking it about 30 to 60 minutes before breakfast or 4 hours after the evening meal before bedtime are both good times to take levothyroxine.
00:06:40 Rachel Cole
And related to this question is whether levothyroxine needs to be separated from other medications, such as calcium, iron, or multivitamins with minerals by 4 hours.
00:06:50 Rachel Cole
We know levothyroxine can interact with a number of different OTCs or prescription meds that can bind to levothyroxine in the gut and reduce its absorption.
00:07:01 Rachel Cole
But following these strict dosing recommendations are often not practical for all of our patients, especially if they may end up not taking it at all.
00:07:11 Rachel Cole
The key is to remind patients that adherence and consistency is key with levothyroxine.
00:07:17 Rachel Cole
And in most cases, this approach gives us a lot more flexibility.
00:07:22 Rachel Cole
If patients can’t handle taking levothyroxine on an empty stomach at all, then let them know that TSH can be monitored and the dose of levothyroxine can be adjusted based on that patient’s usual routine.
00:07:36 Rachel Cole
The same with interacting meds.
00:07:38 Rachel Cole
Tell patients to separate the levothyroxine from the interacting med as close as they can to that four hours.
00:07:45 Rachel Cole
But more importantly, keep that consistent interval between interacting medications.
00:07:51 Rachel Cole
And if they change how they take levothyroxine or an interacting med, advise rechecking TSH about six to eight weeks afterwards and adjusting the dose of levothyroxine if needed.
00:08:03 Rachel Cole
Again, as long as patients are consistent, that levothyroxine dose can be adjusted.
00:08:09 Rachel Cole
Another common question that comes up is desiccated thyroid, such as armor thyroid or liothyronine, synthetic T3, better options than levothyroxine.
00:08:23 Rachel Cole
The quick answer is no.
00:08:25 Rachel Cole
Some patients swear they feel better on desiccated thyroid or when active T3 is added to levothyroxine.
00:08:33 Rachel Cole
But explain that the amount of T3 in desiccated thyroid may be more than the body would normally make, and this could possibly lead to hyperthyroid effects, such as atrial fibrillation or osteoporosis.
00:08:46 Rachel Cole
And DTE is listed on the Beers criteria due to concerns about cardiac effects.
00:08:53 Rachel Cole
Naturally occurring physiological T3 to T4 ratio is about 1 to 13 micrograms, and this ratio is 1 to 4 micrograms in DTE.
00:09:05 Rachel Cole
So the 1 to 4 ratio in the medication contains a higher amount of T3 per T4, about three times more T3 than the natural physiological ratio.
00:09:19 Rachel Cole
Also discourage adding synthetic T3 liothyronine to levothyroxine, except in rare cases such as a thyroidectomy or radioiodine ablation.
00:09:29 Rachel Cole
Caution that this combo might increase cardiovascular risk due to providing more T3 than the body would normally make.
00:09:37 Rachel Cole
If patients want to try it, or if you see these meds combined, suggest using just a small amount of T3, in about a 1:13 or 1:20 ratio of liothyronine to levothyroxine.
00:09:51 Rachel Cole
This smaller ratio might help prevent overtreatment and hyperthyroid effects.
00:09:58 Rachel Cole
Now, FDA is calling for DTE manufacturers to seek approval since these products predate the modern FDA standards for drug approval.
00:10:08 Rachel Cole
The concerns include the unreviewed safety, purity, and potency of these animal-derived medications and possible quality and dosing issues.
00:10:17 Rachel Cole
But the alert indicates FDA isn’t taking immediate action, so patients have time to transition to an FDA-approved med.
00:10:26 Rachel Cole
Let’s help put these concerns in perspective.
00:10:30 Rachel Cole
Widespread adverse effects haven’t been reported.
00:10:33 Rachel Cole
DTE has a long history of clinical use, and patients do see benefit with these meds.
00:10:39 Rachel Cole
More safety studies are needed, which are in the works per FDA, and the American Association of Clinical Endocrinology, or the AACE, reports that they support equitable access to safe and effective thyroid therapies.
00:10:54 Rachel Cole
Now let’s review one last common question, and that’s, should patients switch from desiccated thyroid extract to levothyroxine?
00:11:03 Rachel Cole
Well, it depends on patient preferences and availability from manufacturers.
00:11:08 Rachel Cole
It’s important to acknowledge your patients’ experiences and their preferences.
00:11:13 Rachel Cole
Discuss potential cardiac and bone risk that we touched on earlier.
00:11:17 Rachel Cole
Emphasize the importance of monitoring since some experts observe poor control of hypothyroidism with patients on DTE, possibly due to variation among lots.
00:11:28 Rachel Cole
Support shared decision-making with prescribers and inform patients of the uncertainty around possible DTE shortages due to FDA’s enforcement actions.
00:11:40 Rachel Cole
Use caution and monitor closely if patients switch from DTE to levothyroxine, since conversion formulas in the literature vary.
00:11:49 Rachel Cole
Generally start with a dose equivalent to 75-88 micrograms of levothyroxine per 60 milligrams, or one grain, of desiccated thyroid.
00:11:59 Rachel Cole
Then monitor thyroid levels closely every four to six weeks and adjust as needed.
00:12:05 Rachel Cole
And of course, educate patients to reach out to their prescriber if they have any serious symptoms such as palpitations or heart rate changes, dizziness, or extreme lethargy.
00:12:17 Rachel Cole
Before we wrap up hypothyroidism, let’s keep in mind that you play a key role in preventing mix-ups with any patient on a thyroid medication.
00:12:26 Rachel Cole
The wrong product or dose can cause swings in thyroid levels, leading to changes in weight, sleep, mood, etc.
00:12:34 Rachel Cole
Familiarize yourself with the different options and watch dosing units closely.
00:12:40 Rachel Cole
Look for most hypothyroid med doses to be in micrograms, but watch for prescriptions ordered in milligrams.
00:12:48 Rachel Cole
Mixing up can lead to dosing errors.
00:12:51 Rachel Cole
Or prescribers may order desiccated thyroid in grains or milligrams.
00:12:56 Rachel Cole
Remember that there are about 60 milligrams of desiccated thyroid per grain.
00:13:02 Rachel Cole
Also double-check doses when entering prescriptions.
00:13:05 Rachel Cole
For instance, there are 15 strengths of the brand Tirosint, 12 of Synthroid and 8 of Armor Thyroid.
00:13:13 Rachel Cole
Separate different strengths on pharmacy shelves with bins, shelf tags, etc. to prevent filling prescriptions with the wrong dose.
00:13:22 Rachel Cole
And ensure the patient is aware of any change in brand, medication, product, generic, or strength, and that they receive pharmacist counseling.
00:13:33 Rachel Cole
Since we really didn’t have time to dig into interactions with levothyroxine today, check out our resource, “Levothyroxine Absorption: The Effect of Food and Drugs,” to learn about strategies to help patients handle some important food and drug interactions.
00:13:49 Narrator
Thanks for listening—we hope today’s episode gave you practical insights you can use right away.
00:13:55 Narrator
Now that you’ve listened, pharmacists and pharmacy technicians can receive CE credit. Just log into your Pharmacist’s Letter or Pharmacy Technician’s Letter account and look for the title of this podcast in the list of available CE courses.
00:14:06 Narrator
We’ve linked the resources we mentioned—and more on today’s topic—right in the show notes. Those links will take you straight to our websites, where you’ll find even more concise, evidence-based charts, articles, and tools.
00:14:18 Narrator
If you’re not yet a subscriber, now’s the time—sign up today to stay ahead with trusted, unbiased insights, and continuing education. Listeners save 10% on a new or upgraded subscription just use code cc1026 at checkout.
00:14:35 Narrator
Looking for more? Check out our other TRC podcasts like Medication Talk and Rumor vs Truth, or dive deeper with our full Pharmacy Essential Updates webinar series.
00:14:45 Narrator
Thanks for listening… stay sharp, stay current—and join us next time on Clinical Capsules!
Clinical Capsules
