amitriptyline vs levothyroxine
Side-by-side comparison of amitriptyline and levothyroxine. Data from FDA drug databases (Orange Book, NDC Directory, recalls, shortages) covering 20,000+ approved drugs, plus CMS pricing; see our methodology.
minor Known Drug Interaction
7.5 Antidepressant Therapy Concurrent use of tricyclic (e.g., amitriptyline) or tetracyclic (e.g., maprotiline) antidepressants and levothyroxine sodium may increase the therapeutic and toxic effects of both drugs, possibly due to increased receptor sensitivity to catecholamines. 7.5 Antidepressant Therapy Concurrent use of tricyclic (e.g., amitriptyline) or tetracyclic (e.g., maprotiline) antidepressants and levothyroxine sodium may increase the therapeutic and toxic effects of both drugs, possibly due to increased receptor sensitivity to catecholamines.
Recommendation: Your doctor should monitor you closely for any unusual symptoms or increased drug effects while taking this combination.
Elavil
Synthroid, Levoxyl, Tirosint
Amitriptyline is a medicine used to treat depression. It may take up to 30 days to feel the full effect.
Levothyroxine is a medicine that replaces a hormone normally made by your thyroid gland. It is used when the thyroid doesn't make enough hormone on its own.
Amitriptyline is used to relieve the symptoms of depression. It works best for a type of depression called endogenous depression. This is depression that comes from within, rather than being caused by outside events.
This medicine treats hypothyroidism, a condition where the thyroid gland doesn't make enough thyroid hormone. It can be used in adults and children, even newborns. Levothyroxine can also be used after surgery and radioiodine therapy for thyroid cancer to help lower thyroid-stimulating hormone (TSH) levels.
Amitriptyline belongs to a class of drugs called tricyclic antidepressants (TCAs). It works by increasing the levels of certain chemicals in your brain. These chemicals help improve your mood.
Levothyroxine provides a synthetic form of thyroxine (T4), which is the main hormone produced by the thyroid gland. Your body converts T4 into triiodothyronine (T3), the active form of the hormone. By providing T4, levothyroxine helps restore normal thyroid hormone levels in your body.
- • Drowsiness
- • Dizziness
- • Weakness
- • Fatigue
- • Headache
- • Fatigue
- • Increased appetite
- • Weight loss
- • Feeling hot
- • Headache
- Pain 1,564
- Feeling sick to your stomach 1,434
- Head pain 1,380
- Tiredness 1,369
- Shortness of breath 1,340
- Tiredness 25,847
- Feeling sick to your stomach 22,021
- Head pain 18,798
- Loose stools 18,178
- Difficulty breathing 16,216
Antidepressants may increase the risk of suicidal thoughts or actions in children, teens, and young adults. Your doctor should closely monitor you for worsening depression or unusual changes in behavior. Amitriptyline is not approved for use in children.
Thyroid hormones, including levothyroxine, should not be used for weight loss or to treat obesity. Using high doses can cause serious and life-threatening side effects, especially when taken with stimulant medicines.
Tell your doctor if you are pregnant, plan to become pregnant, or are breastfeeding. It is not known if amitriptyline will harm your unborn baby. Amitriptyline can pass into breast milk.
Tell your doctor if you are pregnant or plan to become pregnant. Your levothyroxine dose may need to be adjusted during pregnancy. Levothyroxine passes into breast milk, but it is not expected to harm the baby.
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How to Read This amitriptyline vs levothyroxine Comparison
amitriptyline is classified in the Tricyclic Antidepressant (TCA) drug class, while levothyroxine sits within the Thyroid Hormone class. Drugs from different classes work through distinct mechanisms, so a head-to-head comparison illustrates trade-offs rather than equivalence. Both drugs are prescription-only, so a licensed provider must authorize use.
Adverse event totals above are pulled from the FDA's Adverse Event Reporting System (FAERS). For these top-ranked reactions alone, amitriptyline has 7,087 submissions while levothyroxine has 101,060. Those figures reflect cumulative reporting volume, not per-patient risk, so older, widely dispensed drugs typically look worse on count alone. These two drugs have a known minor interaction flagged in FDA labeling, attributed to using these drugs together can make your body more sensitive to certain chemicals, which may increase the side effects of both medications.. Serious warnings, pregnancy guidance, and contraindications can differ even when indications overlap.
A table cannot substitute for clinical judgment. Effectiveness, tolerability, drug-drug interactions with your other medications, kidney and liver function, pregnancy status, insurance formulary, and price all feed into a decision that only a licensed prescriber can make responsibly. Data here is sourced from FDA Structured Product Labels (SPL) and FAERS, both of which update as manufacturers and clinicians submit new information. This page is for educational purposes only, is not medical advice, and should not be used to self-switch between amitriptyline and levothyroxine - always consult your physician or pharmacist first.
Important: This comparison is for informational purposes only. Drug effects vary between individuals. Always consult your doctor or pharmacist for personalized medical advice.