Drug interactions between levothyroxine and Tegretol XR
| Results for the following 2 drugs: |
|---|
| levothyroxine |
| Tegretol XR (carbamazepine) |
Interactions between your selected drugs
carbamazepine ↔ levothyroxine
Applies to:Tegretol XR (carbamazepine) and levothyroxine
MONITOR: Carbamazepine and phenytoin may decrease exogenous thyroid plasma concentrations resulting in elevated thyroid stimulating hormone (TSH) and possible exacerbation of hypothyroidism. The mechanism may be induction of hepatic CYP450 enzymes responsible for thyroxine (T4) and triiodothyronine (T3) metabolism. In addition, T3 and T4 may be displaced from thyroxine binding globulin by phenytoin. Clinical data are limited.
MANAGEMENT: Clinical monitoring of patient response, including laboratory serum TSH concentrations, is recommended. Adjustment of the thyroid replacement dosage may be indicated when initiating or discontinuing phenytoin or carbamazepine therapy.
See also...
Drug Interaction Classification
The classifications below are a guideline only. The relevance of a particular drug interaction to a specific patient is difficult to determine using this tool alone given the large number of variables that may apply.
| Major | Highly clinically significant. Avoid combinations; the risk of the interaction outweighs the benefit. |
| Moderate | Moderately clinically significant. Usually avoid combinations; use it only under special circumstances. |
| Minor | Minimally clinically significant. Minimize risk; assess risk and consider an alternative drug, take steps to circumvent the interaction risk and/or institute a monitoring plan. |
Do not stop taking any medications without consulting your healthcare provider.
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