Conversion Table

Thyroid Extract LT4 Equivalencies

Full Replacement (1.6mcg/kg LT4)

Disclaimer

All information contained in this website and its associated web applications is provided for educational purposes only and should not be used for diagnosis or treatment of any illness. Use of these applications is not intended to guide patient care or to replace clinical judgement. The creator of this website is not responsible for errors or for any consequences from application of this website-- its content, calculators, and applications. The creator makes no warranty, expressed or implied, with respect to accuracy or currency of this website, its associated web applications , or its references. Application of these tools remains the responsibility of the practitioner.

LT4 and Combined T4:T3 Equivalencies


Notes: goal is to have combination T4 and T3 therapy reflect physiologic T4 to T3 ratio of 13:1 to 16:1 (or up to 20:1 in European guidelines)

Some methods will have much different ratios because or effects of rounding to nearest dose strength, and some are trying to account for differing absorption of T4 and T3

Thyroid extracts have a non-physiologic T4 to T3 ratio of approximately 4:1

Reference

Alternative LT4 Dosing Frequencies

Usage: Input a target daily LT4 dose as well as a current LT4 dosage formulation in order to output how many days per week to take the current LT4 dose to have equivalent weekly dose as target LT4 daily dose

Results:

Table Example:

Thionamide Dose



Disclaimer

All information contained in this website and its associated web applications is provided for educational purposes only and should not be used for diagnosis or treatment of any illness. Use of these applications is not intended to guide patient care or to replace clinical judgement. The creator of this website is not responsible for errors or for any consequences from application of this website-- its content, calculators, and applications. The creator makes no warranty, expressed or implied, with respect to accuracy or currency of this website, its associated web applications , or its references. Application of these tools remains the responsibility of the practitioner.

Guide: Score of 45 or more is highly suggestive of thyroid storm, 25-44 supports diagnosis, below 25 makes thyroid storm unlikely

Reference

Thyroid Storm Treatment:

  • PTU 200mg q4-6h or MMI 20mg q4-6h
  • Propranolol 60-80mg po q4-6h (or esmolol gtt [250 to 500 mcg/kg IVB + 50 to 100 mcg/kg per minute])
  • ONE HOUR AFTER thionamide admin: potassium iodide-iodine (Lugol's) solution 10 drops (6.25 mg iodide/iodine per drop [0.05 mL]) three times daily OR SSKI 5 drops (50 mg iodide/drop [0.05 mL]) every six hours
  • Hydrocortisone 100mg q6h
  • cholestyramine 4g orally QID (especially if intolerant to thionamides)


Disclaimer

All information contained in this website and its associated web applications is provided for educational purposes only and should not be used for diagnosis or treatment of any illness. Use of these applications is not intended to guide patient care or to replace clinical judgement. The creator of this website is not responsible for errors or for any consequences from application of this website-- its content, calculators, and applications. The creator makes no warranty, expressed or implied, with respect to accuracy or currency of this website, its associated web applications , or its references. Application of these tools remains the responsibility of the practitioner.

Guide: Score >60:likely myxedema coma, 25-59: suggestive of myxedema coma, below 24 makes myxedema coma unlikely

Reference

Myxedema Coma Treatment

  • LT4 200-400mcg IVB, then 50-100mcg IV daily (lower doses for older adults or CVD)
  • T3 5-20mcg IVB, then 2.5-10mcg IV q8h (lower dose for older adults or CVD)
  • Hydrocortisone 100mg q8h until AI excluded
  • Passive (not active) rewarming


Disclaimer

All information contained in this website and its associated web applications is provided for educational purposes only and should not be used for diagnosis or treatment of any illness. Use of these applications is not intended to guide patient care or to replace clinical judgement. The creator of this website is not responsible for errors or for any consequences from application of this website-- its content, calculators, and applications. The creator makes no warranty, expressed or implied, with respect to accuracy or currency of this website, its associated web applications , or its references. Application of these tools remains the responsibility of the practitioner.

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