carbamazepine vs levothyroxine
Side-by-side comparison of carbamazepine 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. Phenytoin and carbamazepine reduce serum protein binding of levothyroxine, and total and free T4 may be reduced by 20% to 40%, but most patients have normal serum TSH levels and are clinically euthyroid. Other drugs: Carbamazepine Furosemide (> 80 mg IV) Heparin Hydantoins Non-Steroidal Anti-inflammatory Drugs - Fenamates These drugs may cause protein-binding site displacement.
Recommendation: Your doctor may need to check your thyroid levels and adjust your dose if you start or stop taking this medication.
Tegretol
Synthroid, Levoxyl, Tirosint
Carbamazepine is a medicine used to control seizures and treat nerve pain. It works by reducing abnormal electrical activity in the brain and calming nerve signals.
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.
Carbamazepine is used to treat certain types of seizures, including partial seizures and generalized tonic-clonic seizures. It can also treat mixed seizure patterns. Carbamazepine also treats the pain from trigeminal neuralgia, a nerve disorder that causes intense facial pain. It is also sometimes used for glossopharyngeal neuralgia.
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.
Carbamazepine is an anticonvulsant. It works by reducing the spread of seizure activity in the brain. It also stabilizes nerve impulses to reduce pain.
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
- • Drowsiness
- • Unsteadiness
- • Nausea
- • Vomiting
- • Fatigue
- • Increased appetite
- • Weight loss
- • Feeling hot
- • Headache
- Seizure 3,609
- Interaction with another medicine 3,369
- Fall 3,044
- Dizziness 2,860
- Fever 2,690
- Tiredness 25,847
- Feeling sick to your stomach 22,021
- Head pain 18,798
- Loose stools 18,178
- Difficulty breathing 16,216
Carbamazepine can cause severe skin reactions, including Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN), which can be fatal. If you are of Asian descent, you may need a blood test before starting this medicine. Carbamazepine can also cause serious blood problems like aplastic anemia and agranulocytosis. Contact your doctor right away if you develop a fever, sore throat, rash, or unusual bleeding or bruising.
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.
Carbamazepine may harm an unborn baby. Talk to your doctor if you are pregnant or plan to become pregnant. It is not known if carbamazepine passes into breast milk, so talk to your doctor about 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 carbamazepine vs levothyroxine Comparison
carbamazepine is classified in the Anticonvulsant 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, carbamazepine has 15,572 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 carbamazepine changes how thyroid hormone travels in your blood, which can lower the levels of hormone found in medical tests.. 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 carbamazepine 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.