Thyroid Hormone Toxicity Treatment & Management: Prehospital, Emergency Department, and Inpatient Care

Concurrent use of tyrosine-kinase inhibitors such as imatinib may cause hypothyroidism. Patients The SYNTHROID dosage is based on the target level of TSH suppression for the stage and clinical status of thyroid cancer. The recommended daily dosage of SYNTHROID in pregnant patients is described in Table 3. Levothyroxine (T4) overdose is not frequently encountered and for the clinical signs to materialize, the ingested dose, the rate of conversion of T4 to T3 and chronicity of overdose can be held accountable. Because symptoms generally revolve around cardiovascular manifestations of thyrotoxicosis, admit to a cardiac monitored bed while appropriate beta blockade, IV hydration, and control of agitation and hyperthermia are achieved. Administering activated charcoal to a patient who has co-ingested a sedative is fraught with danger.

Patient resources

The peak therapeutic effect of a given dose of SYNTHROID may not be attained for 4 to 6 weeks. Pregnant and lactating females need to discuss the dose and use of this medication with their caregivers. This document does not contain all possible side effects and others may occur.

1. Case report

• Rapid restoration of normal serum T4 concentrations is essential for preventing the adverse effects of congenital hypothyroidism on cognitive development as well as on overall physical growth and maturation.
• Monitor patients receiving concomitant SYNTHROID and sympathomimetic agents for signs and symptoms of coronary insufficiency.
• Levothyroxine injection is used in adults to treat myxedema coma.
• Consult the regional poison control center or local medical toxicologist (certified through the American Board of Medical Toxicology or the American Board of Emergency Medicine) for additional information and patient care recommendations.

The physiological actions of thyroid hormones are produced predominantly by T3, the majority of which (approximately 80%) is derived from T4 by deiodination in peripheral tissues. Reduce the SYNTHROID dosage or discontinue temporarily if signs or symptoms of overdosage occur. Initiate appropriate supportive treatment as dictated by the patient’s medical status. Levothyroxine (T4) overdose is not a common entity and it can occur accidently, mostly in children, and can happen intentionally in adults with suicidal ideation especially psychiatric patients 1. Intentional, massive exposures in excess of 10 mg (10,000 mcg) that present early (within an hour) may benefit from more aggressive decontamination, including gastric lavage, and subsequent administration of activated charcoal. Thyroid function tests are not routinely indicated following thyroxine overdose.

Signs and symptoms of levothyroxine toxicity may not appear for several days after ingestion, and, therefore, close observation preferably on a telemetry floor is recommended until the thyroid hormone levels start to decrease. Effective treatment options include beta-blockers preferably propranolol, early gastric lavage, cholestyramine, and glucocorticoids. While hemodialysis has a limited role, antithyroid drugs and activated charcoal are ineffective. Patients may remain asymptomatic even with a levothyroxine overdose of up to 9 mg in a day. As no standard guidelines are currently available, the management of levothyroxine overdose should be individualized based on the amount ingested, as well as the clinical symptoms and signs of the patient. Patients should be monitored for cardiac arrhythmias and ideally kept under observation on a telemetry floor until their thyroid hormone levels begin to decrease.

Beta-blockers such as propranolol, are useful to ameliorate the metabolic effects of thyroid hormone, mostly on the cardiac system (controlling tachycardia, preventing arrhythmias). Propylthiouracil (PTU) might be used for blocking the conversion of T4 to T3 but may have very limited usefulness in the presence of a large load of LT4. Thyroid hormones exert their physiologic actions through control of DNA transcription and protein synthesis. Triiodothyronine (T3) and L-thyroxine (T4) diffuse into the cell nucleus and bind to thyroid receptor proteins attached to DNA. This hormone nuclear receptor complex activates gene transcription and synthesis of messenger RNA and cytoplasmic proteins.

• Some drugs can affect your thyroid hormone levels and also make levothyroxine less effective.
• These interactions can be avoided if levothyroxine is taken at least 30–60 minutes before consuming any of these foods and beverages.
• TSH may not normalize in some patients due to in utero hypothyroidism causing a resetting of pituitary-thyroid feedback.
• Providing a complete list of medications to the doctor will help with getting the correct dose established for each individual patient.

Intravenous levothyroxine

Atrial fibrillation is the most common of the arrhythmias observed with levothyroxine overtreatment in the elderly. Rapid restoration of normal serum T4 concentrations is essential for preventing the adverse effects of congenital hypothyroidism on cognitive development as well as on overall physical growth and maturation. Therefore, initiate SYNTHROID therapy immediately upon diagnosis. Levothyroxine is generally continued for life in these patients see WARNINGS AND PRECAUTIONS. Initiate SYNTHROID therapy in this population at lower doses than those recommended in younger individuals or in patients without cardiac disease see DOSAGE AND ADMINISTRATION and Use In Specific Populations.

Tell your doctor about all your current medicines and any medicine you start or stop using. Levothyroxine belongs to a class of medications called hormones. It works by replacing thyroid hormone that is normally produced by the body.

Here, we present a case of levothyroxine overdose in a 69-year-old male with ingestion of 9 mg of levothyroxine. Elevated levels of total and free T4 and T3 have been described with suppressed serum TSH levels and otherwise typically a normal biochemical profile (Table 2). In one study the half-life of LT4 was 5.7 days which is slightly shorter than the usual half-life of L-thyroxine.

Remember, keep this and all vicodin synthroid other medicines out of the reach of children, never share your medicines with others, and use Synthroid only for the indication prescribed. Enter medications to view a detailed interaction report using our Drug Interaction Checker. This is given as an injection into a vein by a healthcare provider and should only be used to treat myxedema coma.

Some people might use their levothyroxine prescriptions for this reason, but it’s important to know that the use of levothyroxine for weight loss can result in dangerous and potentially life-threatening side effects. Thyroid hormones can also be present illicitly in some over-the-counter weight loss products. These dietary supplements can contain varying amounts of thyroid hormones, which can be dangerous and cause adverse effects. Because of this, people should not take over-the-counter weight loss supplements. In adult patients with primary hypothyroidism, monitor serum TSH levels after an interval of 6 to 8 weeks after any change in dosage.