Why has levothyroxine been recalled?

Levothyroxine is a synthetic version of the thyroid hormone thyroxine that is used to treat hypothyroidism, an endocrine disorder where the thyroid gland does not produce enough thyroid hormones. Levothyroxine helps replace the thyroxine that the thyroid gland cannot produce and brings thyroid hormone levels back to normal. It is one of the most commonly prescribed medications in the United States and around the world.

Recently, some formulations of levothyroxine have been recalled by the U.S. Food and Drug Administration (FDA) and manufacturers due to issues with potency or subpotency. This means that certain batches of levothyroxine tablets have had higher or lower amounts of the active levothyroxine ingredient than indicated on the label.

Why are drug recalls issued?

In the United States, the FDA is responsible for overseeing the safety and effectiveness of all prescription and over-the-counter drugs. When a pharmaceutical company detects issues with a medication they have manufactured, they are legally required to issue a voluntary drug recall.

Recalls may be issued when:

  • A drug is found to be dangerous or cause harmful side effects
  • A drug is found to be contaminated or contain the wrong ingredients
  • A drug has incorrect or missing labels
  • A drug is not made according to proper manufacturing practices
  • Test results show a drug may not be effective
  • Packaging defects could impact safety or quality

Drug recalls aim to protect consumers from potentially hazardous pharmaceuticals by alerting patients and healthcare professionals about important safety issues. Recalled drugs are removed from the market so they are no longer available to patients.

Recent levothyroxine recalls

In the past few years, there have been several notable recalls involving popular levothyroxine brands:

  • In August 2022, Torrent Pharmaceuticals expanded their voluntary recall to include all lots of levothyroxine and liothyronine (Thyroid Tablets, USP) due to an issue with subpotency.
  • In May 2022, Alvogen recalled one lot of levothyroxine tablets due to potency issues discovered during stability testing.
  • In March 2022, Lannett Company recalled one lot of levothyroxine sodium tablets due to potency issues.
  • In January 2022, American Regent expanded a prior recall to include several more lots of levothyroxine sodium capsules, also due to super potency.
  • In December 2021, American Regent initiated a voluntary recall of one lot of levothyroxine sodium capsules due to super potency.

The above recalls involved popular brand name and generic levothyroxine products from major manufacturers. The reasons for the recalls all involved incorrect amounts of the active levothyroxine ingredient in tablets or capsules.

Signs of super potent or subpotent levothyroxine

When levothyroxine doses are higher or lower than they should be, patients may notice changes in hypothyroidism symptoms or side effects:

Signs of super potent levothyroxine Signs of subpotent levothyroxine
  • Chest pain, irregular heartbeat
  • Shortness of breath
  • Nervousness, anxiety
  • Tremor, tremors
  • Trouble sleeping
  • Frequent bowel movements
  • More sweating than usual
  • Fatigue, tiredness
  • Depression
  • Constipation
  • Dry skin and hair
  • Fluid retention, puffiness
  • Impaired memory
  • Muscle cramps

Why are potency issues occurring with levothyroxine?

There are a few potential reasons why recent batches of levothyroxine may have had incorrect potency leading to the recalls:

  • Manufacturing process errors – Small mistakes in measuring ingredients, mixing compounds, calibrating machinery, or producing tablets could result in incorrect strengths.
  • Equipment failures – If manufacturing equipment is not properly maintained, calibrated, or operating correctly, the right amounts of active ingredients may not get into tablets.
  • Testing inaccuracies – Improper testing or lab errors could lead to inaccurate potency results during stability testing of batches.
  • Formula changes – Adjustments to inactive ingredients or levothyroxine sources may impact potency.
  • Generic substitutions – Slight variations between brand name and generics could cause small potency differences.

Manufacturing quality levothyroxine requires careful control and precision at every step of the production process. Small variations can result in tablets that are super potent or subpotent.

How are patients affected by recalls?

Levothyroxine recalls can have a direct effect on patients taking the medication:

  • May experience return of hypothyroidism symptoms
  • Dose may no longer be effective with subpotent tablets
  • Could have side effects from excessive hormone with super potent tablets
  • Inconvenience of having prescriptions changed or needing more monitoring
  • Concerns over finding new supplies of levothyroxine
  • Problems due to insurance or availability if brands need to be switched

It is important for patients to closely watch for any new symptoms or side effects when taking levothyroxine from a recalled batch. Doctors may need to adjust prescriptions or brands if potency is found to be incorrect.

What should patients do during recalls?

If you are taking levothyroxine tablets or capsules that have been recalled due to potency issues, be sure to follow these steps:

  1. Check the FDA website to see if your specific bottle or pills were affected by the recall.
  2. Contact your pharmacist or doctor immediately if your medication was recalled.
  3. Return any unused portions of the recalled medication to your pharmacy.
  4. Ask your doctor to prescribe a new formulation of levothyroxine.
  5. Have your thyroid hormone levels rechecked within 4-6 weeks after switching medications.
  6. Watch carefully for any return of symptoms or new side effects and report them promptly to your doctor.

Staying on top of any notifications, consulting your healthcare provider, and being vigilant about symptoms can help minimize disruption if your levothyroxine is recalled.

How are recalls prevented in the future?

To avoid additional recalls of levothyroxine in the future, manufacturers can take these steps:

  • Review manufacturing protocols and quality control procedures
  • Upgrade outdated manufacturing equipment
  • Improve employee training on compliance and safety standards
  • Enhance batch testing for potency at multiple timepoints
  • Standardize formulas and sourcing of active pharmaceutical ingredients
  • Increase oversight and audits of production facilities
  • Expand capacity to meet demand and prevent shortages

Preventing drug recalls takes commitment across the entire pharmaceutical supply chain. Levothyroxine manufacturers will need to invest in improving quality standards to restore confidence in this critical medication.

Factor Preventative Measure
Manufacturing Process Review protocols, upgrade equipment, improve training
Formula Changes Standardize ingredients and sources
Testing Enhance batch testing at multiple timepoints
Quality Control Increase oversight and audits
Supply Chain Expand production capacity


Levothyroxine is an essential thyroid hormone replacement medication taken by millions of hypothyroidism patients. Recent recalls due to potency concerns have highlighted vulnerabilities in the drug manufacturing and supply chain. Companies will need to pinpoint the root causes of improper levothyroxine concentrations and invest in improving quality control. With enhanced production standards, testing, and oversight, future recalls may be avoided. In the meantime, patients should stay alert for any notifications from manufacturers, pharmacies, or doctors regarding changes to their levothyroxine prescriptions. Seeking medical advice promptly can help maintain thyroid levels until higher quality formulations are widely available.

Leave a Comment