title: Thyroid function during B-vitamin supplementation of patients on antiepileptic drugs.
abstract: OBJECTIVE
  Patients on antiepileptic drugs (AEDs) may have low serum concentrations of thyroxine, with or without a compensatory increment in thyroid-stimulating hormone (TSH). Furthermore, patients on AEDs often have hyperhomocysteinemia and low concentrations of vitamins B(6), B(2) and folate. Previously, an inverse relationship between thyroxine and homocysteine concentrations has been observed. In animals, deficiency of vitamin B(6) has been found to impair the hypophyseal release of TRH. We have studied the effect of B-vitamin supplements on thyroid function in patients on AEDs.
  
  
  METHODS
  Thirty-two patients on AEDs were identified with hyperhomocysteinemia and low folate, B(6) and B(2). They were supplemented with pyridoxine, riboflavin and folic acid for 30 days.
  
  
  RESULTS
  At baseline, the patients had low serum concentrations of free thyroxin and slightly elevated TSH. On day 30 of the B-vitamin supplements, homocysteine had decreased, however, the thyroid parameters remained unchanged.
  
  
  CONCLUSIONS
  Hyperhomocysteinemic patients on AEDs have indications of hypothyroidism, however, supplementation with B-vitamins does not improve their thyroid function.
authors.affiliation: Department of Medicine, Stavanger University Hospital, Postbox 8100, 4068 Stavanger, Norway. apeland@online.no
authors.forename: Terje
authors.initials: T
authors.lastname: Apeland
authors.forename: Ole
authors.initials: O
authors.lastname: Kristensen
authors.forename: Roald E
authors.initials: RE
authors.lastname: Strandjord
authors.forename: Mohammad A
authors.initials: MA
authors.lastname: Mansoor
mesh_terms: D000328:Adult; D000927:Anticonvulsants / Q000008:administration & dosage / Q000627:therapeutic use*; D016022:Case-Control Studies; D019587:Dietary Supplements; D006711:Homocystine / Q000097:blood; D006801:Humans; D008297:Male; D013960:Thyroid Function Tests; D013961:Thyroid Gland / Q000187:drug effects* / Q000502:physiology*; D013972:Thyrotropin / Q000097:blood; D013974:Thyroxine / Q000097:blood; D014803:Vitamin B Complex / Q000008:administration & dosage* / Q000494:pharmacology*
chemical_list: D000927:Anticonvulsants; D014803:Vitamin B Complex; D006711:Homocystine; D013972:Thyrotropin; D013974:Thyroxine