Levothyroxine side effects

List of side effects
Hyperthyroidism due to therapeutic overdosage Seizures Hypothyroidism Children/infants Hypersensitivity to inactive ingredients

Hyperthyroidism due to therapeutic overdosage
Adverse reactions associated with Levothyroxine therapy are primarily those of hyperthyroidism due to therapeutic overdosage. They include the following: Return to top
 * General: fatigue, increased appetite, weight loss, heat intolerance, fever, excessive sweating;
 * Central Nervous System: headache, hyperactivity, nervousness, anxiety, irritability, emotional lability, insomnia;
 * Musculoskeletal: tremors, muscle weakness;
 * Cardiovascular: palpitations, tachycardia, arrhythmias, increased pulse and blood pressure, heart failure, angina, myocardial infarction, cardiac arrest;
 * Respiratory: dyspnea;
 * Gastrointestinal: diarrhea, vomiting, abdominal cramps and elevations in liver function tests;
 * Dermatologic: hair loss, flushing;
 * Endocrine: decreased bone mineral density;
 * Reproductive: menstrual irregularities, impaired fertility.

Seizures
Seizures have been reported rarely with the institution of Levothyroxine therapy. Return to top

Hypothyroidism
Inadequate Levothyroxine dosage will produce or fail to ameliorate the signs and symptoms of hypothyroidism. Return to top

Children/infants
Pseudotumor cerebri and slipped capital femoral epiphysis have been reported in children receiving Levothyroxine therapy. Overtreatment may result in craniosynostosis in infants and premature closure of the epiphyses in children with resultant compromised adult height. Return to top

Hypersensitivity to inactive ingredients
Hypersensitivity reactions to inactive ingredients have occurred in patients treated with thyroid hormone products. These include urticaria, pruritus, skin rash, flushing, angioedema, various GI symptoms (abdominal pain, nausea, vomiting and diarrhea), fever, arthralgia, serum sickness and wheezing. Hypersensitivity to Levothyroxine itself is not known to occur. Return to top