Levothyroxine is a commonly prescribed medication for hypothyroidism, a condition where the thyroid gland doesn’t produce enough thyroid hormone. This synthetic hormone regulates metabolism, energy levels, and various bodily functions. Due to its narrow therapeutic index, consistent dosing is crucial for maintaining appropriate thyroid hormone levels in the body.
Impact of Expired Levothyroxine on Your Health
Taking expired levothyroxine reduces the medication’s potency. Over time, its active ingredient degrades, leading to a less effective dose. This diminished potency means your body may not receive the necessary amount of thyroid hormone, which can disrupt your thyroid levels.
When levothyroxine loses effectiveness, hypothyroid symptoms may return or worsen. These include:
Fatigue
Unexplained weight gain
Increased sensitivity to cold
Dry skin
Hair loss
Slowed heart rate
Constipation
Joint and muscle pain
Anxiety or depression
Irregular menstrual periods
In young women, undertreatment can lead to subnormal fertility, recurrent pregnancy loss, and compromised fetal growth. For children and adolescents, insufficient treatment can impair growth and development.
Fluctuations in hormone levels, whether from reduced potency or other factors, can lead to adverse health outcomes if not corrected. Untreated or undertreated hypothyroidism can cause increased cardiovascular disease burden, obesity, and hypertension. In severe cases, it may lead to myxedema coma, a life-threatening condition.
Factors Affecting Levothyroxine Stability
Levothyroxine is a sensitive compound, susceptible to degradation from environmental factors. Its potency can decrease over time, which is why manufacturers set expiration dates. The primary environmental elements that accelerate this degradation include light, moisture, heat, and humidity.
Exposure to light, especially direct sunlight, can lead to photodegradation of levothyroxine, reducing its effectiveness. High temperatures and excessive humidity also contribute to the breakdown of the active ingredient. Even variations in air oxygen can affect its stability.
The formulation of levothyroxine tablets also plays a role in its stability. Inactive ingredients (excipients) and packaging protect the medication from environmental factors. However, some excipients, like certain carbohydrates, can interact with levothyroxine and accelerate its degradation. Changes in pH within the formulation can also influence stability. Proper storage and packaging are crucial to preserve potency until the expiration date.
Safe Management of Your Levothyroxine Medication
If your levothyroxine medication has expired, do not take it. The main concern is a loss of potency, meaning it may not provide the full dose needed to manage your thyroid condition. Contact your healthcare provider immediately for a new prescription and to discuss any symptoms.
Proper storage maintains levothyroxine’s stability and effectiveness. Store the medication in a cool, dry place, away from direct sunlight, within 20°C to 25°C (68°F to 77°F). Keep it in its original container to protect it from light and moisture. Avoid storing levothyroxine in humid areas, like bathrooms, as moisture accelerates degradation.
For safe disposal of expired or unused levothyroxine, avoid flushing it down the toilet or throwing it directly into the trash, as this can lead to environmental contamination. Instead, use medication take-back programs, often available at pharmacies or community events. If a take-back program is not accessible, dispose of the medication at home by mixing it with an undesirable substance like dirt or used coffee grounds, placing the mixture in a sealed bag, and discarding it in the household trash. Remember to remove or scratch out personal information on the label before recycling the container.