Thyroid Treatments

Indication

Levothyroxine is the standard, FDA-approved replacement therapy for hypothyroidism (low thyroid hormone). Your provider will monitor your labs to find the precise dose for you.

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Boxed Warning

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Thyroid hormones, including levothyroxine, should not be used for the treatment of obesity or for weight loss. Larger doses may produce serious or even life-threatening manifestations of toxicity, particularly when given with sympathomimetic amines such as those used for their anorectic effects.

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Contraindications

• Uncorrected adrenal insufficiency.

Warnings & Precautions

• Cardiac adverse reactions in the elderly and in patients with underlying cardiovascular disease.
• Acute myocardial infarction.
• Worsening of diabetic control; decreased bone density with long-term over-replacement.

Drug Interactions

Many medications and foods affect absorption or thyroid levels — including calcium, iron, antacids, certain cholesterol medications, proton pump inhibitors, estrogens, and soy. Separate dosing as directed and tell your provider all medications and supplements you take.

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Use in Specific Populations

• Pregnancy: thyroid hormone needs often increase during pregnancy; do not stop, and tell your provider promptly if you become pregnant.
• Breastfeeding: compatible at appropriate doses.
• Older adults and patients with heart disease are usually started at lower doses.

Common Side Effects

Most adverse effects reflect over-replacement (too much thyroid hormone): arrhythmias, dyspnea, muscle spasm, headache, nervousness, irritability, insomnia, tremors, muscle weakness, increased appetite, weight loss, diarrhea, heat intolerance, menstrual irregularities, and skin rash.

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Storage & Missed Dose

Take once daily on an empty stomach, usually 30–60 minutes before breakfast, with water. Store at room temperature, away from moisture. If you miss a dose, take it as soon as you remember; if it is almost time for the next dose, skip it do not double up. Do not switch brands/formulations without your provider's guidance.
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Read the Medication Guide and Patient Information provided with your prescription before you start taking this medication and each time you get a refill.
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You are encouraged to report negative side effects of prescription products to the FDA: visit www.fda.gov/medwatch or call 1-800-FDA-1088.

Indication

Liothyronine (T3) may be added to, or used in place of, T4 therapy when standard treatment does not fully address symptoms such as fatigue or brain fog.

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Boxed Warning

Thyroid hormones should not be used for the treatment of obesity or for weight loss. Toxicity can occur, especially when combined with sympathomimetic amines.

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Contraindications

• Uncorrected adrenal insufficiency.
• Artificial rewarming.

Warnings & Precautions

• Cardiovascular disease.
• Diabetes.
• Worsening of cardiovascular conditions; bone effects with over-replacement.

Drug Interactions

Similar interactions to levothyroxine  calcium, iron, antacids, and certain other medications affect thyroid levels. Tell your provider all medications and supplements you take.

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Use in Specific Populations

• Pregnancy/breastfeeding: tell your provider; thyroid needs may change.
• Use lower starting doses and closer monitoring in older adults and those with heart disease.

Common Side Effects

Similar to levothyroxine, driven largely by hyperthyroidism from therapeutic overdosage (e.g., tremors, palpitations, nervousness, sweating).

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Storage & Missed Dose

Take as directed. Store at room temperature. If you miss a dose, take it when you remember unless near the next dose  do not double up.
‍
Read the Medication Guide and Patient Information provided with your prescription before you start taking this medication and each time you get a refill.
‍
You are encouraged to report negative side effects of prescription products to the FDA: visit www.fda.gov/medwatch or call 1-800-FDA-1088.

Indication

NDT is a whole-thyroid (T4 + T3) replacement option derived from porcine thyroid that may be considered for some patients; your provider will review your history to determine if it aligns with your goals.
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Boxed Warning

Thyroid hormones, either alone or with other therapeutic agents, should not be used for the treatment of obesity or for weight loss.
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Contraindications

• Uncorrected adrenal insufficiency.
• Untreated thyrotoxicosis.
• Hypersensitivity to pork or beef products (depending on formulation).

Warnings & Precautions

• Use with caution in patients with cardiovascular disease.
• Potency can vary between products; consistent monitoring is important.

Drug Interactions

Same absorption and interaction considerations as other thyroid hormones (calcium, iron, antacids, and others). Tell your provider all medications and supplements you take.

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Use in Specific Populations

• Pregnancy/breastfeeding: tell your provider; do not stop without guidance.
• Lower starting doses and closer monitoring in older adults and those with heart disease.

Common Side Effects

Palpitations, tachycardia, arrhythmias, weight loss, angina, tremor, headache, diarrhea, nervousness, insomnia, sweating, and heat intolerance.
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Storage & Missed Dose

Take once daily as directed, ideally on an empty stomach. Store at room temperature. If you miss a dose, take it when you remember unless near the next dose — do not double up.
‍
Read the Medication Guide and Patient Information provided with your prescription before you start taking this medication and each time you get a refill.
‍
You are encouraged to report negative side effects of prescription products to the FDA: visit www.fda.gov/medwatch or call 1-800-FDA-1088.

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Ozempic® and Wegovy® are registered trademarks of Novo Nordisk A/S. Mounjaro® and Zepbound® are registered trademarks of Eli Lilly and Company. Foundayo™ is a trademark of Eli Lilly and Company. Saxenda® and Victoza® are registered trademarks of Novo Nordisk A/S. Contrave® is a registered trademark of Currax Pharmaceuticals LLC. Vivelle-Dot® and Doti® are registered trademarks of Novartis AG. Climara® is a registered trademark of Bayer. Veozah® is a registered trademark of Astellas Pharma Inc.

Editorial / regulatory note: GLP-1 ISI for Wegovy, Ozempic, Zepbound, and Foundayo was adapted from publicly published DTC safety pages; Mounjaro and Saxenda/Victoza ISI was drafted from FDA-approved prescribing information in the same format.
All ISI must be verified against the most current FDA-approved prescribing information for each product and approved by legal/regulatory before publication.