The contraindications of levothyroxine sodium tablets (Euthyrox) involve specific populations, food interactions, and medication restrictions, which must be strictly adhered to avoid treatment risks. The following provides a detailed explanation from three aspects: classification of contraindicated populations, list of contraindicated foods, and special restrictions, with emphasis on cardiovascular risks and absorption interference factors.

1. Prohibited groups

(1) Absolute taboo

Patients with untreated adrenal insufficiency are prohibited from using this product, as it may induce an adrenal crisis. Prior to use, patients must be supplemented with glucocorticoids.

Patients with acute myocardial infarction in the acute phase are prohibited from using thyroid hormones, as they may exacerbate myocardial oxygen consumption and lead to worsening of the condition.

(2) Relative taboo

Patients with severe cardiovascular disease need to start with an extremely low dosage (12.5-25μg/day) and adjust slowly every 6-8 weeks.

Elderly patients (especially those aged >65) have high cardiac sensitivity, and the initial dose should be reduced by 30%-50%, with monitoring for palpitations.

2. Taboo foods

(1) Significant interference absorption

Soy products (soybean milk/tofu) can reduce the absorption rate by 40%, and they should be consumed at least 4 hours apart.

High-fiber foods (wheat bran/oats) combined with drug ingredients, it is recommended to avoid consuming them for breakfast or adjust the medication time.

(2) Affect the stability of drug efficacy

Grapefruit juice inhibits the metabolic enzyme CYP3A4, which may increase plasma drug concentration. It is necessary to avoid simultaneous intake.

Foods containing calcium/iron (such as milk/spinach) form chelates, which should be taken at least 4 hours apart.

3. Restrictive conditions

(1) Restrictions on medication administration methods

It must be taken on an empty stomach (30-60 minutes before breakfast), as eating can decrease bioavailability by 20%-60%.

When used in combination with a bile acid sequestrant (colestyramine), it is necessary to administer the medication with an interval of more than 12 hours.

(2) Disease state restrictions

Patients with myxedema coma are prohibited from taking oral medication and require emergency treatment with intravenous thyroid hormone preparations.

Patients with diabetes need to monitor their blood sugar frequently, as thyroid hormones may weaken the effect of hypoglycemic agents.

(3) Special monitoring requirements

During treatment, TSH/FT4 should be monitored every 4-6 weeks to avoid excessive levels leading to decreased bone density, especially in postmenopausal women.

Regular assessment of bone age is necessary for children on long-term medication to prevent premature closure of cranial sutures and growth restriction.