From the Guidelines
Hypothyroidism is a condition where the thyroid gland doesn't produce enough thyroid hormones, and treatment typically involves daily oral levothyroxine (synthetic T4) with a target TSH of 0.5-2.5 mIU/L for most adults, as recommended by recent guidelines 1.
Symptoms of Hypothyroidism
- Fatigue
- Cold intolerance
- Weight gain
- Dry skin
- Constipation
- Depression These symptoms occur because thyroid hormones regulate metabolism throughout the body, affecting energy production, heart function, brain development, and many other critical processes.
Treatment Options
- Daily oral levothyroxine (synthetic T4) with starting doses usually between 25-125 mcg depending on age, weight, severity, and cardiac status
- Elderly patients or those with heart disease should start at lower doses (12.5-25 mcg) with gradual increases
- The medication should be taken on an empty stomach, 30-60 minutes before breakfast or 3-4 hours after the last meal of the day, avoiding calcium, iron supplements, and certain foods that can interfere with absorption
- TSH levels should be checked 6-8 weeks after starting treatment or changing doses, with a target TSH of 0.5-2.5 mIU/L for most adults, as recommended by recent guidelines 1
- Once stabilized, annual monitoring is recommended
Management of Immune-Related Adverse Events
- For grade 1 hypothyroidism, continue ICPi with monitoring of TSH every 4-6 weeks as part of routine care
- For grade 2 hypothyroidism, may continue or hold ICPi until symptoms resolve to baseline, and consider endocrine consultation for unusual clinical presentations
- For grade 3-4 hypothyroidism, hold ICPi until symptoms resolve to baseline with appropriate supplementation, and consider endocrine consultation to assist with rapid hormone replacement, as recommended by recent guidelines 1
Quality of Life and Mortality
- Proper treatment of hypothyroidism is essential to improve quality of life and reduce mortality, as thyroid hormones play a critical role in regulating metabolism and energy production throughout the body
- Recent guidelines emphasize the importance of monitoring TSH levels and adjusting treatment accordingly to achieve optimal outcomes 1
From the FDA Drug Label
Pediatric Patients at Risk for Hyperactivity To minimize the risk of hyperactivity, start at one-fourth the recommended full replacement dosage, and increase on a weekly basis by one-fourth the full recommended replacement dosage until the full recommended replacement dosage is reached Hypothyroidism in Pregnant Patients For pregnant patients with pre-existing hypothyroidism, measure serum TSH and free-T4 as soon as pregnancy is confirmed and, at minimum, during each trimester of pregnancy. In pregnant patients with primary hypothyroidism, maintain serum TSH in the trimester-specific reference range The general aim of therapy is to normalize the serum TSH level TSH may not normalize in some patients due to in utero hypothyroidism causing a resetting of pituitary-thyroid feedback. Failure of the serum T4 to increase into the upper half of the normal range within 2 weeks of initiation of levothyroxine sodium therapy and/or of the serum TSH to decrease below 20 IU per litre within 4 weeks may indicate the patient is not receiving adequate therapy
The symptoms of hypothyroidism are not directly stated in the label, but the treatment options include:
- Levothyroxine sodium tablets to normalize the serum TSH level
- Dosage adjustment:
- Start at one-fourth the recommended full replacement dosage and increase on a weekly basis by one-fourth the full recommended replacement dosage until the full recommended replacement dosage is reached
- Increase levothyroxine sodium dosage by 12.5 to 25 mcg per day in pregnant patients
- Monitor TSH every 4 weeks until a stable dose is reached and serum TSH is within normal trimester-specific range
- Monitoring:
- Assess the adequacy of therapy by periodic assessment of laboratory tests and clinical evaluation
- Monitor serum TSH levels after an interval of 6 to 8 weeks after any change in dosage
- Evaluate clinical and biochemical response every 6 to 12 months and whenever there is a change in the patient’s clinical status 2
From the Research
Symptoms of Hypothyroidism
- The symptoms of hypothyroidism are due to slow metabolism, such as constipation, fatigue, sensitivity to cold, weight gain, etc. 3
- Polysaccharide accumulation in certain tissues can lead to hoarseness, eyelid swelling, etc. 3
- Common symptoms include cold intolerance, fatigue, weight gain, dry skin, constipation, and voice changes 4
- Symptoms may be absent in subclinical hypothyroidism 5
Diagnosis of Hypothyroidism
- Diagnosis is based on blood levels of thyroid-stimulating hormone (TSH) and free thyroxine (T4) 4, 6
- A blood TSH concentration of less than 4 or 5 mlU/L rules out peripheral hypothyroidism 3
- TSH levels increase with age 3
- Between 30% and 60% of high TSH levels are not confirmed on a second blood test 3
Treatment Options for Hypothyroidism
- Levothyroxine therapy is the standard treatment for hypothyroidism 3, 4, 5
- The initial dose of levothyroxine should be adjusted based on the patient's age, weight, and general condition 3, 4
- Patients older than 60 years or with known or suspected ischemic heart disease should start at a lower dosage of levothyroxine (12.5 to 50 mcg per day) 3, 4
- Treatment monitoring is based mainly on blood TSH assay, and dose adjustment should only be considered after 6 to 12 weeks 3
- Combined levothyroxine plus liothyronine treatment is not recommended as standard therapy, but may be considered in patients with persistence of symptoms despite optimal levothyroxine treatment 7
Special Considerations
- Women with hypothyroidism who become pregnant should increase their weekly dosage of levothyroxine by 30% up to nine doses per week 4
- Patients with subclinical hypothyroidism may not benefit from treatment unless the TSH level is greater than 10 mIU per L or the thyroid peroxidase antibody is elevated 4, 5
- The risk of progression to overt hypothyroidism is about 3% to 4% per year overall, but increases with the initial TSH level 3