Types of patients with hypothyroidism

Some patients with hypothyroidism can be challenging to treat and require special consideration. Use this section to review the cases of Steve, Jennifer, and Diana to see how to effectively manage their hypothyroidism with Synthroid (levothyroxine sodium).

Steve, 50

Recently diagnosed patient*

  • Recently diagnosed with hypothyroidism
  • Initiating treatment
Review Steve’s chart

Jennifer, 32

Pregnant patient*

  • Diagnosed with hypothyroidism 3 years ago
  • Started and managed on levothyroxine
Review Jennifer’s chart

Diana, 70

Elderly patient*

  • Diagnosed with hypothyroidism 10 years ago
  • Gastroesophageal reflux disease (GERD) diagnosed 6 months ago
Review Diana’s chart

Recently diagnosed patient*

Steve is a 50-year-old man with hypothyroidism.

Past Medical History:

  • 4 months ago, 190-lb patient presented with weight gain of 20 pounds in 1 year. Patient complained of fatigue, dry skin, constipation, cold intolerance, TSH 10.2 mIU/L, BP 150/60, total cholesterol 235 mg/dL; patient was diagnosed with hypothyroidism and started on Synthroid 137 mcg
  • 8 weeks later, patient’s complaints continued. TSH 4.6 mIU/L; Synthroid dose increased to 150 mcg

Current Complaint:

  • Nervousness, agitation, palpitations, and feeling hot for the past few months

Current Medications:

  • Synthroid 150 mcg

Notable Physical Exam and Lab Findings:

  • Sweating profusely despite air-conditioned exam room
  • TSH 0.3 mIU/L

Diagnosis:

  • Patient is displaying symptoms of being overreplaced with current dose of Synthroid of 150 mcg; TSH test confirmed

Treatment Plan Considerations:

  • Decrease dose of Synthroid
  • Recheck TSH levels in 4-6 weeks

*Hypothetical patient profile.

Clinical insights

  • Managing hypothyroidism requires frequent monitoring
    • Study of more than 1500 patients found that 40% of patients being treated for hypothyroidism were not within the normal therapeutic TSH range15

Many patients on thyroid medication struggle to reach optimal TSH levels15,16

The Colorado Thyroid Disease Prevalence Study

The Colorado Study, a cross-sectional study of patients (N=25,862) at a statewide health fair in 1995, found that only 60% of hypothyroidism patients receiving replacement therapy had normal TSH levels.

25 mcg
orange

Treatment Adequacy Study

A retrospective Treatment Adequacy study was conducted between 2013-2020 and found that over 20 years later, ~20% of patients taking thyroid medication still do not achieve normal TSH levels.

25 mcg
orange

Overall, 81.1% ([CI: 80.4-81.8]; N=9130) of patients had normal mean TSH levels and 11.7% [CI: 11.1-12.3; N=1312] and 7.3% [CI: 6.8-7.8; N=817] had high and low TSH levels, respectively.

Achieving steady TSH levels and hormonal stability requires precise, individualized dosing, and adequate monitoring is essential in stabilizing TSH levels.2

  • Under- or overmedicating can have serious effects2
  • With a narrow therapeutic range, even small dose changes in levothyroxine, including Synthroid, can affect TSH levels2
Study design
Study design

The Carr study: proof that precise dosing matters17

Adapted from a 1988 biochemical study conducted in 21 adult Caucasian patients in the United Kingdom with primary hypothyroidism who were tested on a series of different thyroxine dosages to evaluate effectiveness of measuring TSH levels to monitor thyroid function.

Effect on TSH levels of 25-mcg change in levothyroxine dose17,18

The chart shows how thyroid-stimulating hormone (TSH) levels vary for 21 patients after adjustments to their levothyroxine dosage. For many patients, small changes in dosage—either increasing or decreasing by 25 micrograms—caused significant shifts in their TSH levels. The majority of patients' optimal TSH levels fall within a recommended therapeutic range, but the chart highlights the sensitivity of TSH levels to dose changes, emphasizing the importance of careful and individualized dosing to maintain stability.
Study design

Pregnant Patient*

Jennifer is a 32-year-old woman in her first trimester of pregnancy with hypothyroidism that is managed on Synthroid.

Past Medical History:

  • Diagnosed with hypothyroidism 3 years ago
  • Started and managed on 50 mcg Synthroid
  • Weight fluctuation
  • Appendectomy

Current Complaint:

  • Fatigue and facial puffiness

Current Medications:

  • Synthroid 50 mcg

Notable Physical Exam and Lab Findings:

  • Young woman with cold, dry skin and facial puffiness
  • TSH 6.2 mIU/L

Diagnosis:

  • Patient is displaying symptoms of hypothyroidism due to subtherapeutic dosing of Synthroid; TSH test confirmed

Treatment Plan Considerations:

  • Increase dosage of Synthroid
  • Recheck TSH levels in 4 weeks

*Hypothetical patient profile.

Clinical insights

TSH levels may increase during pregnancy. TSH should be monitored and Synthroid dosage adjusted during pregnancy.1

  • 2017 ATA Guidelines state that19:
    • Between 50% and 85% of treated hypothyroid women need to increase their levothyroxine dosing during pregnancy

See pregnancy guidelines

Elderly patient*

Diana is a 70-year-old woman who has a history of hypothyroidism that has been managed on 112 mcg of Synthroid for the past 5 years.

Past Medical History:

  • Hypothyroidism diagnosed 10 years ago
  • Gastroesophageal reflux disease (GERD) diagnosed 6 months ago
  • Enlarged thyroid

Current Complaint:

  • Increasing hair loss, fatigue, chronic constipation for the past few months

Current Medications:

  • Synthroid 112 mcg
  • Daily fiber supplements
  • Proton pump inhibitor (PR)

Notable Physical Exam and Lab Findings:

  • Well-nourished elderly woman with 
thinning hair
  • TSH 5.7 mIU/L

Diagnosis:

  • Patient is displaying symptoms of hypothyroidism (TSH test confirmed), most likely due to the initiation of a PPI and the concurrent use of daily fiber supplements

Treatment Plan Considerations:

  • Counseled patient to take Synthroid on an empty stomach and at least 4 hours before or after other medications
  • Recheck TSH levels in 6-8 weeks

*Hypothetical patient profile.

Clinical insights

  • Certain medications, supplements, and foods can affect absorption of levothyroxine, including SYNTHROID1
    • Gastric acidity is essential for adequate absorption of levothyroxine; therefore, administration of a PPI may affect the intragastric pH, which can reduce absorption
    • Levothyroxine should be taken on an empty stomach and at least 4 hours before or after medications known to interfere with absorption
    • Dietary fiber may bind and decrease the absorption of levothyroxine from the gastrointestinal tract
  • The Third National Health and Nutrition Examination Survey (NHANES III) data have shown that the rate of elevated TSH (>4.5 mIU/L) increased with age20
The chart summarizes findings from the NHANES III survey (1988–1994), which measured thyroid-stimulating hormone (TSH) levels in a population of over 13,000 people. It shows that the percentage of individuals with elevated TSH levels (greater than 4.5 mIU/L) increases with age. The youngest age groups, such as 12–19 and 20–29, have the lowest percentages, around 2%. The percentage rises gradually across decades, reaching over 10% in those aged 80 and older. This data highlights that older age groups are more likely to have elevated TSH levels, suggesting an age-related trend in thyroid function.