Treatment algorithm

Please note that formulations/routes and doses may differ between drug names and brands, drug formularies, or locations. Treatment recommendations are specific to patient groups: see disclaimer

ONGOING

non-pregnant non-lactating adults without mass effect

1st line – radioactive iodine therapy (I-131)

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non-pregnant non-lactating adults without mass effect
1st line – 

radioactive iodine therapy (I-131)

Patient values and preferences are an important part of any therapeutic decision-making about definitive treatment. For example, patients choosing I-131 therapy would most likely favour avoidance of issues surrounding surgery, such as anaesthesia or hospitalisation, and their possible complications.[1] I-131 is a preferred treatment for most non-pregnant and non-lactating patients.

Dose is generally either fixed; calculated based on goitre size; or computed based on amount of radiation to be delivered.[24]

Antithyroid drugs, if used adjunctively, are stopped 3 to 5 days before I-131 treatment and restarted 3 to 5 days afterward.

I-131 may worsen thyrotoxicosis for several days due to thyroid hormone leakage.[44]

Contraindicated in pregnant or lactating women. Pregnancy test in women of childbearing age is required prior to therapy.[24]

Caution required in older adults, especially in those with cardiac disease.[24] Those patients require consideration of pretreatment with antithyroid drugs, and careful monitoring.

Occasionally a second dose is required 3 to 6 months after the first dose.

Consider – pretreatment with antithyroid drugs

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non-pregnant non-lactating adults without mass effect
Consider – 

pretreatment with antithyroid drugs

Additional treatment recommended for SOME patients in selected patient group

May be useful for pretreatment of older adults, those with severe symptoms, or those with comorbidities such as heart disease.

Can also be restarted, if needed, after I-131 therapy is given. Some controversy exists as to the necessity for pre-treatment antithyroid drugs if symptoms are controlled with beta-blockade.[1]

Thiamazole is the preferred drug, due to a higher risk of hepatotoxicity with propylthiouracil. Thiamazole also has the advantage of less-frequent dosing.

Rare but serious complications include agranulocytosis (0.1% to 0.5% of patients) or liver toxicity.[45]

Vasculitis can occur with propylthiouracil.[46]

Primary options

thiamazole: 5-60 mg/day orally given once daily or in 2-3 divided doses; doses rarely exceed 40 mg/day in practice

Secondary options

propylthiouracil: 50-400 mg/day orally given in 3 divided doses

2nd line – subtotal thyroidectomy

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non-pregnant non-lactating adults without mass effect
2nd line – 

subtotal thyroidectomy

The hyperthyroidism of toxic thyroid adenoma generally does not remit spontaneously, and therefore definitive treatment is usually required. Patient values and preferences are an important part of any therapeutic decision-making about definitive treatment. For example, those choosing surgery may prefer avoidance of radioactivity, desire very rapid control of hyperthyroidism, or have a lower concern about risks of surgery.[1]

Surgery is an option for those resistant to, or who decline, radioactive iodine, or who prefer surgery. Reduction of thyroid function is immediate, although recurrent hyperthyroidism or subsequent hypothyroidism is possible.

Complications include rare recurrent laryngeal nerve damage and hypoparathyroidism. An experienced, high-volume surgeon is recommended.[1]

Consider – pretreatment with antithyroid drugs

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ONGOING
|
non-pregnant non-lactating adults without mass effect
Consider – 

pretreatment with antithyroid drugs

Additional treatment recommended for SOME patients in selected patient group

Given prior to surgery to normalise thyroid function, especially for older patients and for those with severe symptoms or comorbidities such as heart disease. Regular monitoring of thyroid function is required.

Thiamazole is the preferred drug, due to a higher risk of hepatotoxicity with propylthiouracil. Thiamazole also has the advantage of less-frequent dosing.

Rare but serious complications include agranulocytosis (0.1% to 0.5% of patients) or liver toxicity.[45]

Vasculitis can occur with propylthiouracil.[46]

Primary options

thiamazole: 5-60 mg/day orally given once daily or in 2-3 divided doses; doses rarely exceed 40 mg/day in practice

Secondary options

propylthiouracil: 50-400 mg/day orally given in 3 divided doses

3rd line – antithyroid drugs alone

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ONGOING
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non-pregnant non-lactating adults without mass effect
3rd line – 

antithyroid drugs alone

Not usually first-line therapy in non-pregnant patients, because remission of hyperthyroidism in patients with toxic adenoma is rare.[6]

Thiamazole is the preferred drug, due to a higher risk of hepatotoxicity with propylthiouracil. Thiamazole also has the advantage of less-frequent dosing.

Also used when required before surgery or I-131 therapy, especially for older patients, for those with severe symptoms or comorbidities such as heart disease, or when more definitive therapies are contraindicated or refused.

Regular monitoring of thyroid function is required.

Rare but serious complications include agranulocytosis (0.1% to 0.5% of patients) or liver toxicity.[45]

Vasculitis can occur with propylthiouracil.[46]

Primary options

thiamazole: 5-60 mg/day orally given once daily or in 2-3 divided doses; doses rarely exceed 40 mg/day in practice

Secondary options

propylthiouracil: 50-400 mg/day orally given in 3 divided doses

Plus – beta-blockers pending effects of definitive treatment

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ONGOING
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non-pregnant non-lactating adults without mass effect
|
with moderate/severe symptoms and/or increased cardiovascular risk
Plus – 

beta-blockers pending effects of definitive treatment

Treatment recommended for ALL patients in selected patient group

Used for symptoms such as palpitations, anxiety, or tremor.[34][44] Also used for patients at higher cardiovascular risk, although caution is needed in the presence of heart disease. Generally recommended for older adults with symptoms or younger people with heart rate >90 bpm.[1]

Dose gradually increased until symptoms and pulse are controlled, then tapered when patient is euthyroid.

Useful prior to surgery or I-131 therapy, or while waiting for antithyroid drugs to take effect.

A selective beta-blocker (e.g., atenolol) can be used for patients who cannot tolerate propranolol.

If beta-blockers are contraindicated, an alternative is a calcium-channel blocker.

Primary options

propranolol: 10-40 mg orally (immediate-release) four times daily

Secondary options

atenolol: 25-50 mg orally once daily, increase if necessary to 100 mg/day

non-pregnant non-lactating adults with mass effect

1st line – subtotal thyroidectomy

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ONGOING
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non-pregnant non-lactating adults with mass effect
1st line – 

subtotal thyroidectomy

Option for patients with obstructive symptoms such as choking, hoarseness or dyspnoea that are caused by very large nodules.[1]

Reduction of thyroid function is immediate, although recurrent hyperthyroidism or subsequent hypothyroidism is possible.

An experienced, high-volume surgeon is recommended.[1] Complications include rare recurrent laryngeal nerve damage and hypoparathyroidism. Hypocalcaemia due to hypoparathyroidism may be transient or permanent.

Consider – pretreatment with antithyroid drugs

Back
ONGOING
|
non-pregnant non-lactating adults with mass effect
Consider – 

pretreatment with antithyroid drugs

Additional treatment recommended for SOME patients in selected patient group

Thyroid function is normalised prior to surgery. Regular monitoring of thyroid function is required.

Thiamazole is the preferred drug, due to a higher risk of hepatotoxicity with propylthiouracil. Thiamazole also has the advantage of less-frequent dosing.

Rare but serious complications include agranulocytosis (0.1% to 0.5% of patients) or liver toxicity.[45]

Vasculitis can occur with propylthiouracil.[46]

Primary options

thiamazole: 5-60 mg/day orally given once daily or in 2-3 divided doses; doses rarely exceed 40 mg/day in practice

Secondary options

propylthiouracil: 50-400 mg/day orally given in 3 divided doses

2nd line – radioactive iodine therapy (I-131)

Back
ONGOING
|
non-pregnant non-lactating adults with mass effect
2nd line – 

radioactive iodine therapy (I-131)

Radioactive iodine is a less-preferred option than surgery in patients with large masses causing compressive symptoms, but can be utilised when surgery is contraindicated or refused. Nodule shrinkage may occur post-treatment.[36][37][38]

I-131 therapy is contraindicated in pregnancy and during lactation.

Consider – pretreatment with antithyroid drugs

Back
ONGOING
|
non-pregnant non-lactating adults with mass effect
Consider – 

pretreatment with antithyroid drugs

Additional treatment recommended for SOME patients in selected patient group

Useful for pretreatment of older adults, those with severe symptoms, or those with comorbidities such as heart disease.

Thiamazole is the preferred drug, due to a higher risk of hepatotoxicity with propylthiouracil. Thiamazole also has the advantage of less-frequent dosing.

Rare but serious complications include agranulocytosis (0.1% to 0.5% of patients) or liver toxicity.[45]

Vasculitis can occur with propylthiouracil.[46]

Primary options

thiamazole: 5-60 mg/day orally given once daily or in 2-3 divided doses; doses rarely exceed 40 mg/day in practice

Secondary options

propylthiouracil: 50-400 mg/day orally given in 3 divided doses

Plus – beta-blockers pending effects of definitive treatment

Back
ONGOING
|
non-pregnant non-lactating adults with mass effect
|
with moderate/severe symptoms and/or increased cardiovascular risk
Plus – 

beta-blockers pending effects of definitive treatment

Treatment recommended for ALL patients in selected patient group

Used for symptoms such as palpitations, anxiety, or tremor.[34][44] Also used for patients at higher cardiovascular risk, although caution is needed in the presence of heart disease. Generally recommended for older adults with symptoms or younger people with heart rate >90 bpm.[1]

Dose gradually increased until symptoms and pulse are controlled, then tapered when patient is euthyroid.

Useful prior to surgery or I-131 therapy, or while waiting for antithyroid drugs to take effect.

A selective beta-blocker (e.g., atenolol) can be used for patients who cannot tolerate propranolol.

If beta-blockers are contraindicated, an alternative is a calcium-channel blocker.

Primary options

propranolol: 10-40 mg orally (immediate-release) four times daily

Secondary options

atenolol: 25-50 mg orally once daily, increase if necessary to 100 mg/day

pregnant or lactating

1st line – antithyroid drugs

Back
ONGOING
|
pregnant or lactating
1st line – 

antithyroid drugs

Thiamazole is the preferred drug except in the first trimester of pregnancy, due to a higher risk of hepatotoxicity with propylthiouracil. Because of possible congenital defects (e.g., aplasia cutis) associated with thiamazole, propylthiouracil has been preferred during the first trimester.[39] However, more recent data suggest there may also be a rare propylthiouracil-associated embryopathy with defects of the urinary system and face/neck.[40] Thiamazole also has the advantage of less-frequent dosing.

Pregnant women should be managed by a multidisciplinary team. Maternal and fetal hypothyroidism must be avoided to prevent damage to fetal neural development, risk of miscarriage, or preterm delivery. Generally doses of antithyroid drugs are lower in pregnancy, and maternal levels of free thyroid hormones are kept high-normal to slightly elevated. Women wishing to breast-feed should have specialty care to discuss dosing of antithyroid drugs to minimise the infant's exposure.[47] Low-to-moderate doses (e.g., thiamazole <20 mg/day) of antithyroid drugs can be safely used during lactation.[41]

Subclinical hyperthyroidism (suppressed thyroid-stimulating hormone [TSH] with normal levels of free thyroid hormones) during pregnancy does not require drug treatment.

Rare but serious complications include agranulocytosis (0.1% to 0.5% of patients), liver toxicity or vasculitis.[45][46]

Primary options

propylthiouracil: 50-300 mg/day orally given in 3 divided doses; consult specialist for further guidance

OR

thiamazole: 5-30 mg orally once daily or given in 2-3 divided doses; consult specialist for further guidance

2nd line – subtotal thyroidectomy

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ONGOING
|
pregnant or lactating
2nd line – 

subtotal thyroidectomy

Rarely required. Possible reasons for subtotal thyroidectomy during pregnancy include serious adverse reaction to antithyroid drugs which precludes their use; non-adherence to or marked resistance to antithyroid drugs, leading to uncontrolled hyperthyroidism;[41] or severe compressive symptoms.

When performed, the second trimester is the preferred time for surgery.[41] An experienced, high-volume surgeon is recommended.

Complications include rare recurrent laryngeal nerve palsy and hypoparathyroidism.

Plus – beta-blockers pending effects of definitive treatment

Back
ONGOING
|
pregnant or lactating
|
with moderate/severe symptoms and/or increased cardiovascular risk
Plus – 

beta-blockers pending effects of definitive treatment

Treatment recommended for ALL patients in selected patient group

Used for symptoms such as palpitations, anxiety, or tremor.[44] Also used for patients at higher cardiovascular risk.

Dose gradually increased until symptoms and pulse are controlled, then tapered when patient is euthyroid.

Useful while waiting for antithyroid drugs to take effect, or in the rare instance of surgery.

Labetalol is considered the safest beta-blocker in pregnancy. Propranolol may be used for the short-term control of hyperthyroid symptoms in pregnant women, but its use has been associated with fetal bradycardia and growth restriction.

Primary options

propranolol: consult specialist for guidance on dose

OR

labetalol: consult specialist for guidance on dose

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Please note that formulations/routes and doses may differ between drug names and brands, drug formularies, or locations. Treatment recommendations are specific to patient groups. See disclaimer

Use of this content is subject to our disclaimer