As a synthetic thyroid hormone replacement medication, Levothyroxine Sodium Tablets (Euthyrox) are widely used in the treatment of hypothyroidism and suppressive therapy after thyroid cancer surgery. Although the drug has definite efficacy, improper use may lead to severe adverse reactions.

What Are the Side Effects of Levothyroxine Sodium Tablets (Euthyrox)?

Cardiovascular System

Palpitations, tachycardia, arrhythmias (including atrial fibrillation), elevated blood pressure; in severe cases, angina pectoris, myocardial infarction, or even cardiac arrest may occur.

Nervous System

Central nervous system hyperstimulation manifestations such as headache, tremors, insomnia, anxiety, irritability, and emotional instability.

Digestive System

Diarrhea, vomiting, abdominal cramps; approximately 30% of patients may experience abnormal liver function indicators.

Metabolic Aspects

Typical hyperthyroid metabolic manifestations including increased appetite with weight loss, heat intolerance, and excessive sweating.

Others

Muscle spasms, hair loss, menstrual disorders, skin rashes, etc.

Severe Adverse Reactions of Levothyroxine Sodium Tablets (Euthyrox) Requiring High Alert

Cardiotoxic Events

Improper medication use in elderly patients or those with pre-existing cardiovascular diseases may induce life-threatening ventricular arrhythmias.

Acute myocardial infarction.

Aggravation of congestive heart failure.

Adrenal Crisis

Patients with concurrent adrenal insufficiency who use Euthyrox directly without prior glucocorticoid supplementation may develop refractory hypotension.

Severe electrolyte disturbances.

Manifestations of adrenal crisis such as circulatory failure.

Myxedema Coma

Excessively rapid correction of severe hypothyroidism may induce heart failure.

Changes in neurological symptoms need to be monitored in the early stage of treatment.

Metabolic Dysregulation

Diabetic patients may experience deterioration of blood glucose control, requiring adjustment of hypoglycemic regimens.

Long-term excessive medication use in postmenopausal women may lead to aggravated osteoporosis and increased fracture risk.

Precautions for Taking Levothyroxine Sodium Tablets (Euthyrox)

Key Points for Treatment Monitoring

Primary hypothyroidism: Monitor TSH every 6-8 weeks until the condition stabilizes, then recheck every 6-12 months.

Thyroid cancer patients: Control the TSH target based on tumor risk stratification.

Pregnant women: Monitor thyroid function every 4 weeks, and immediately resume the pre-pregnancy dose after delivery.

Warnings for Contraindicated Populations

Absolutely contraindicated in patients with uncorrected adrenal insufficiency.

Use with caution in the acute phase of acute myocardial infarction.

Contraindicated in patients allergic to any excipient in the preparation.