Eurolev Drug Interactions

Levothyroxine sodium increases the effect of anticoagulants and it may be necessary to reduce the dose of anticoagulant if excessive hypoprothrombinaemia and bleeding are to be avoided.
Phenytoin levels may be increased by levothyroxine sodium.
Anticonvulsants such as carbamazepine and phenytoin enhance the metabolism of thyroid hormones and may displace them from plasma proteins.
Initiation or discontinuation of anticonvulsant therapy may alter levothyroxine sodium dose requirements.
If co-administered with cardiac glycosides, adjustment of dosage of cardiac glycoside maybe necessary.
The effects of sympathomimetic agents are also enhanced.
Levothyroxine sodium increases receptor sensitivity to catecholamines thus accelerating the response to tricyclic antidepressants.
Cholestyramine given concurrently reduces the gastrointestinal absorption of levothyroxine sodium.
Co-administration of oral contraceptives may result in an increased dosage requirement of thyroid therapy.
A number of drugs may affect thyroid function tests, and this should be borne in mind when monitoring a patient on levothyroxine sodium therapy.