liothyronine vs propranolol

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Side-by-side comparison of liothyronine 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 Class
liothyronine Thyroid Hormone (T3)
propranolol Non-Selective Beta-Blocker
Type
liothyronine Prescription
propranolol Prescription
Summary
liothyronine

Liothyronine (Cytomel) is a medicine that replaces a thyroid hormone called T3. It helps your body work properly if you don't make enough thyroid hormone on your own.

propranolol

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.

What It Treats
liothyronine

This medicine treats hypothyroidism, a condition where your thyroid gland doesn't make enough thyroid hormone. It can also be used with surgery and radiation to manage thyroid cancer. Liothyronine can also be used for thyroid suppression tests to check for mild hyperthyroidism.

propranolol

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.

How It Works
liothyronine

Liothyronine is a synthetic form of the T3 thyroid hormone. It works by increasing thyroid hormone levels in your body. This helps to regulate your body's metabolism and energy levels.

propranolol

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.

Common Side Effects
liothyronine
  • Fatigue
  • Increased appetite
  • Weight loss
  • Feeling hot
  • Fever
propranolol
  • Tiredness
  • Dizziness
  • Nausea
  • Vomiting
  • Diarrhea
FAERS Reports
liothyronine
  • Headache 859
  • Fatigue 816
  • Nausea 569
  • Dyspnoea 549
  • Pain 469
propranolol
  • Nausea 4,279
  • Headache 3,785
  • Fatigue 3,752
  • Diarrhoea 3,119
  • Dizziness 3,102
Serious Warnings
liothyronine

This medicine should not be used for weight loss or to treat obesity. Taking high doses of thyroid hormone for weight loss can cause serious and life-threatening side effects, especially when taken with stimulant medicines.

propranolol

Propranolol is contraindicated in people with cardiogenic shock, very slow heart rate, asthma, or those who are allergic to it.

Pregnancy
liothyronine

Tell your doctor if you are pregnant or plan to become pregnant. Your dose of liothyronine may need to be adjusted during pregnancy. This medicine passes into breast milk, but it is not expected to harm your baby.

propranolol

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 liothyronine vs propranolol Comparison

liothyronine is classified in the Thyroid Hormone (T3) 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, liothyronine has 3,262 submissions while propranolol has 18,037. 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 high doses of this blood pressure medicine can change the amount of thyroid hormones found in your blood.. Serious warnings, pregnancy guidance, and contraindications can differ even when indications overlap.

A table cannot represent individual circumstances. Data here is sourced from FDA Structured Product Labels (SPL) and FAERS, both of which update as manufacturers and clinicians submit new information. This registry does not provide medical, treatment, substitution, or medication-change directions for liothyronine or propranolol.

Registry boundary: This comparison displays source-record fields and does not provide individualized medical direction.