Thyroid preparation overdose: MedlinePlus Medical Encyclopedia
A 34 year-old female with a past medical history of Hashimoto thyroiditis (currently taking thyroxine 200 mcg daily) who took an overdose 6 hours ago. The patient claims to have taken 60 x 200 mcg of thyroxine and 10 x 10 mg of temazepam. The patient currently has ‘normal’ vital signs (GCS of 15) and is feeling tired but is otherwise asymptomatic. Currently available studies have not demonstrated increased risk to the fetus in pregnant women taking levothyroxine.
Start at a lower starting dosage and increase the dosage every 4 to 6 weeks as needed based on clinical and laboratory response. Prehospital management includes gathering evidence of ingestion, administration of charcoal in alert patients with an exposure of more than 5 mg of thyroxine, a full initial assessment, oxygen, and intravenous access as necessary. All local poison control centers in the United States use this national number.
- Laboratory workup usually reveals elevated serum total T4 and T3, suppressed serum TSH, and elevated Free T4 and Free T3.
- In addition, many drugs and foods affect T4 absorption see DRUG INTERACTIONS.
- Thyroxine (T4) and triiodothyronine (T3) levels rise within 1 to 2 hours of ingestion.
- A copy of the written consent is available for review by the Editor-in-Chief of this journal on request.
- Concurrent use of ketamine and SYNTHROID may produce marked hypertension and tachycardia.
Larger doses may produce serious or even life-threatening manifestationsof toxicity, particularly when given in association with sympathomimetic amines such as those used for their anorectic effects. Hypersensitivity reactions to inactive ingredients have occurred in patients treated with thyroid hormone products. These include urticaria, pruritus, skin rash, flushing, angioedema, various gastrointestinal symptoms (abdominal pain, nausea, vomiting and diarrhea), fever, arthralgia, serum sickness, and wheezing. Hypersensitivity to levothyroxine itself is not known to occur.
- LT-4 tablets are dissolved by the gastric juice, but there are no data about the rate of dissolution of a large number of tablets of LT-4.
- Pregnancy, infectious hepatitis, estrogens, estrogen-containing oral contraceptives, and acute intermittent porphyria increase TBG concentration.
- This list is not complete and many other drugs may interact with levothyroxine.
- You should not use levothyroxine if you are allergic to glycerin or edetate disodium, or if you have an untreated or uncontrolled adrenal gland disorder.
- In patients on a stable and appropriate replacement dosage, evaluate clinical and biochemical response every 6 to 12 months and whenever there is a change in the patient’s clinical status.
- Cholestyramine, an ion-exchange resin (Questran ®), can be administered in the usual dose of 4 grams every 8 hours orally.
Table 1. Thyroid hormone levels, liver enzyme levels, and heart rate measurements from day one to day nine.
However, this patient is fully conscious and her level of consciousness is unlikely to deteriorate now that 6 hours have passed since the time of ingestion. A “thyrotoxic storm” is never an early feature of acute thyroxine ingestion, even if the dose is massive. You should not use levothyroxine if you are allergic to glycerin or edetate disodium, or if you have an untreated or uncontrolled adrenal gland disorder. You are encouraged to report negative side effects of prescription drugs to the FDA. Seizures have been reported rarely with the institution of levothyroxine therapy. Inquire whether patients are taking biotin or biotin-containing supplements.
What Are Side Effects of Synthroid?
Monitor patients receiving concomitant SYNTHROID and sympathomimetic agents for signs and symptoms of coronary insufficiency. Ensure the patient ingests the full amount of the suspension. Do not administer in foods that decrease absorption of SYNTHROID, such as soybean-based infant formula see DRUG INTERACTIONS. Employ the following treatment approach synthroid rp in acute levothyroxine overdose.
- 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.
- Adequate levothyroxine treatment during lactation may normalize milk production in hypothyroid lactating mothers with low milk supply.
- Secondary hypothyroidism is when the problem is in the pituitary gland, and there is a decrease in the production of thyroid-stimulating hormone (TSH).
Levothyroxine toxicity is rare, but it can sometimes occur accidentally, especially in children. If someone takes too much levothyroxine, symptoms might not occur for several days. Symptoms of levothyroxine overdose include irregular heartbeat, headache, anxiety, agitation, shaking, fatigue, confusion, and disorientation.
Symptoms of levothyroxine overdose may vary depending on age, metabolism, etc. There are no specific guidelines for treating levothyroxine poisoning. Here, we present the case of a 69-year-old man with a history of panhypopituitarism, hypertension, and end-stage renal disease who attempted suicide by ingesting 60 tablets of 150 µg levothyroxine (9 mg). Upon presentation to the emergency room, he was asymptomatic despite the free thyroxine level above the range of the assay.
Oral levothyroxine is primarily indicated for treating primary, secondary, and tertiary hypothyroidism. Primary hypothyroidism is when the problem occurs in the thyroid gland. Secondary hypothyroidism is when the problem is in the pituitary gland, and there is a decrease in the production of thyroid-stimulating hormone (TSH). Additionally, levothyroxine has FDA approval for pituitary thyrotropin suppression as an adjunct to surgery and radioiodine therapy to manage thyrotropin-dependent well-differentiated thyroid cancer.
Emergency department care
Massive amounts of levothyroxine may be ingested intentionally or accidentally. The most common intentional reasons include weight loss and suicidal ideation among others. A potentially toxic dose includes acute ingestion of more than 5 mg of levothyroxine or 0.75 mg of triiodothyronine 3. Given the varied presentations of levothyroxine overdose and a lack of clear benefits of various treatment modalities, treatment of levothyroxine poisoning is challenging, and there are no specific guidelines available.
The estimated background risk of major birth defects and miscarriage for the indicated population is unknown. All pregnancies have a background risk of birth defect, loss, or other adverse outcomes. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2% to 4% and 15% to 20%, respectively.