furosemide vs levothyroxine
Side-by-side comparison of furosemide 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
Other drugs: Carbamazepine Furosemide (> 80 mg IV) Heparin Hydantoins Non-Steroidal Anti-inflammatory Drugs - Fenamates These drugs may cause protein-binding site displacement. Furosemide has been shown to inhibit the protein binding of T4 to TBG and albumin, causing an increase free T4 fraction in serum. Furosemide competes for T4-binding sites on TBG, prealbumin, and albumin, so that a single high dose can acutely lower the total T4 level.
Recommendation: Your doctor may need to monitor your thyroid levels closely if you are taking high doses of furosemide. They will check to see if your medication dose needs to be changed.
Lasix
Synthroid, Levoxyl, Tirosint
Furosemide is a water pill (diuretic). It helps your body get rid of extra water and salt.
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.
This medicine treats swelling (edema) from heart failure, liver problems, or kidney disease. It can also treat high blood pressure. Furosemide is helpful when you need a stronger diuretic.
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.
Furosemide works in your kidneys. It helps your kidneys remove more salt and water from your blood. This lowers the amount of fluid in your body and lowers blood pressure.
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.
- • Dizziness
- • Headache
- • Blurred vision
- • Nausea
- • Vomiting
- • Fatigue
- • Increased appetite
- • Weight loss
- • Feeling hot
- • Headache
- Difficulty breathing 29,099
- Tiredness 20,389
- Diarrhea 19,940
- Feeling sick to your stomach 18,682
- Sudden kidney damage 18,530
- Tiredness 25,847
- Feeling sick to your stomach 22,021
- Head pain 18,798
- Loose stools 18,178
- Difficulty breathing 16,216
Furosemide can cause you to lose too much fluid and electrolytes. This can lead to dehydration, low blood pressure, and kidney problems. Your doctor should check your blood regularly while you are taking this medicine.
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 or plan to become pregnant. Furosemide may not be safe during pregnancy. Talk to your doctor about the risks and benefits of taking this medicine while breastfeeding.
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 furosemide vs levothyroxine Comparison
furosemide is classified in the Loop Diuretic 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, furosemide has 106,640 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 high doses of this water pill can knock thyroid hormones off the proteins they usually travel on in your blood. this changes how much active thyroid hormone is available for your body to use.. 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 furosemide 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.