Hyperthyroidism (Overactive Thyroid): Drug Therapy

Therapeutic target

Achieve a euthyroid metabolic state (= thyroid levels in the normal range).

Therapy recommendations

• Hyperthyroidism
  • Thyrostatic agents (drugs that inhibit thyroid function: thiamazole, carbimazole) because of hyperthyroidism in Graves’ disease and autonomy
    • M. Graves’ disease: one-year (to one and a half years) thyrostatic therapy.
    • SD autonomy: hyperthyroidism is treated with medication only until definitive therapy in the form of radioiodine therapy or surgery can be performed
  • Perchlorate (indication: prophylaxis before contrast administration; therapy for amiodarone-induced thyroid dysfunction; therapy for thyroid crisis or iodine-induced hyperthyroidism).
• Hyperthyroidism in fertility and pregnancy (= gestational hyperthyroidism).
• Thyrotoxic crisis: this always requires intensive medical treatment with balancing of fluid/electrolyte balance; furthermore:
  • Blockade of thyroid hormone synthesis and secretion.
    • Thyrostatic agents (thiamazole, carbimazole).
    • High-dose administration of iodine to block hormone release from the thyroid gland (“plumming”):
    • Perchlorate in iodine-induced hyperthyroidism; iodine in non-iodine-induced hyperthyroidism.
    • Colestyramine to lower circulating thyroid hormones by inhibiting the enterohepatic circulation of thyroid hormones.
  • Blockade of thyroid hormone action.
    • Beta-blockers to decrease sensitivity to catecholamines (biogenic amines norepinephrine and dopamine (primary catecholamines) and epinephrine and its derivatives) and to control heart rate
    • Glucocorticoids to inhibit the conversion of T4 to T3.
  • Supportive measures
    • High-caloric parenteral nutrition (caloric requirements extremely increased!).
    • Sedation
    • Thrombosis prophylaxis
    • Non-pharmocological measures:
      • Circulatory and pulmonary function monitoring.
      • Reduction of body temperature by physical measures
      • Early ventilation; indications: onset of central nervous symptoms with dysphagia (dysphagia) and coma and/or in cases of pulmonary congestion.
  • Treatment of the underlying disease or the triggering cause.
  • In iodine-induced thyrotoxic crisis, plasmapheresis (therapeutic plasma exchange, TPA) for hormone elimination and subsequent total thyroidectomy (thyroidectomy) should be performed simultaneously.
• Amiodarone and thyroid dysfunction (see below).
• Hyperthyroidism in fertility and pregnancy (= gestational hyperthyroidism) (see below).
• See also under “Further therapy“.

Amiodarone and thyroid dysfunction

Therapy-resistant thyroid dysfunction occurs in 40% of cases during amiodarone therapy; this is caused by the high iodine content or immune-related cytotoxic effects. Two types of amiodarone-induced hyperthyroidism (AIH) are distinguished:

• AIH type I (thyrotoxicosis induced by jodexcess in the presence of preexisting thyroid disease).
• AIH type II (amiodarone-triggered inflammatory-destructive (“inflammatory-destructive”) action on the thyroid gland with increased thyroid hormone release).

Therapy recommendations

• AIH type I: discontinue amiodarone; for therapy: thionamide, perchlorate, and lithium; thyroidectomy is the treatment option for severe type I forms.
• AIH type II: glucocorticoids.

Note: Mild increases in fT4 are normal with amiodarone administration.

Hyperthyroidism in fertility and pregnancy (= gestational hyperthyroidism)

• Hyperthyroidism in the 1st trimester (third trimester): before starting therapy for gestational hyperthyroidism (HCG-induced hyperthyroidism), differential diagnosis of immunogenic hyperthyroidism or autonomous adenoma with manifest hyperthyroidism must be excluded.
• HCG-induced hyperthyroidism: iodine can be passed/100 μg iodide from the normalization of TSH (usually from the 2nd trimester / pregnancy third); if necessary, depending on the symptoms: administration of a beta blocker.
• Immunogenic hyperthyroidism: prevalence approximately 0.5-2/1,000 pregnancies; basically improves by various mechanisms in the second trimester and often also heals completely
• Mild immunogenic hyperthyroidism with positive TRAK: pause iodine.
• Immunogenic hyperthyroidism requiring therapy: 1st trimester propylthiouracil (PTU), then switch to thiamazole/carbimazole; during therapy: TSH should be suppressed (cave. maternal hypothyroidism), free thyroid hormones in upper reference range [endocrinology consult recommended].
• Isolated latent hyperthyroidism in pregnancy: no therapy.