levothyroxine vs propranolol
Side-by-side comparison of levothyroxine and propranolol. 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
Drug or Drug Class Effect Beta-adrenergic antagonists (e.g., Propranolol > 160 mg/day) In patients treated with large doses of propranolol (> 160 mg/day), T3 and T4 levels change, TSH levels remain normal, and patients are clinically euthyroid. Drug or Drug Class Effect Beta-adrenergic antagonists (e.g., Propranolol > 160 mg/day) In patients treated with large doses of propranolol (> 160 mg/day), T3 and T4 levels change, TSH levels remain normal, and patients are clinically euthyroid.
Recommendation: Your doctor may monitor your thyroid blood tests if you take high doses of propranolol. Usually, no change in your thyroid medication is needed.
Synthroid, Levoxyl, Tirosint
Inderal
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.
Propranolol is a medicine that can help with high blood pressure, chest pain, and other conditions. It works by blocking the effects of certain natural chemicals in your body, like adrenaline, that affect the heart and blood vessels.
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.
Propranolol tablets can treat high blood pressure. It can be used alone or with other medicines. Propranolol can also help with chest pain (angina), control fast heart rate with atrial fibrillation, improve survival after a heart attack, prevent migraine headaches, and reduce tremors. It can also help with symptoms of some tumors.
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.
Propranolol is a beta-blocker. It works by blocking the effects of adrenaline on your heart and blood vessels. This helps to slow down your heart rate and lower your blood pressure.
- • Fatigue
- • Increased appetite
- • Weight loss
- • Feeling hot
- • Headache
- • Tiredness
- • Dizziness
- • Nausea
- • Vomiting
- • Diarrhea
- Tiredness 25,847
- Feeling sick to your stomach 22,021
- Head pain 18,798
- Loose stools 18,178
- Difficulty breathing 16,216
- Feeling sick to your stomach 4,279
- Pain in your head 3,784
- Feeling very tired 3,752
- Loose, watery stools 3,121
- Feeling lightheaded or unsteady 3,102
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.
Propranolol is contraindicated in people with cardiogenic shock, very slow heart rate, asthma, or those who are allergic to it.
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.
Tell your doctor if you are pregnant or plan to become pregnant. Propranolol may affect your baby. Talk to your doctor about the risks and benefits of taking propranolol during pregnancy or while breastfeeding.
Also Compare, Nearby Drugs
Compare propranolol with
How to Read This levothyroxine vs propranolol Comparison
levothyroxine is classified in the Thyroid Hormone drug class, while propranolol sits within the Non-Selective Beta-Blocker 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, levothyroxine has 101,060 submissions while propranolol has 18,038. 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 taking large doses of this blood pressure medicine can change the levels of thyroid hormones in your blood. however, it usually does not change how your thyroid actually functions or how you feel.. 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 levothyroxine and propranolol - 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.