Effects of restricting levothyroxine dosage strength availability

Kenneth B. Ain, Frank Pucino, Gyorgy Csako, Robert A. Wesley, Jan A. Drass, Charles Clark, Paul Ketteridge, Keith Crawford, Steve M. Banks, Thomas E. Dorworth

Research output: Contribution to journalArticlepeer-review

4 Scopus citations


We conducted a prospective, randomized, controlled trial to assess whether hospital formulary restrictions involving limiting dosage strengths of levothyroxine affect physicians' ability to manage patients effectively and provide pharmacy cost savings in a tertiary care federal government research hospital. Thirty-three endocrinologists were randomly assigned to prescribe levothyroxine from a restrictive (dosage strengths of 25, 50, 100, 125, and 150 μg) or a nonrestrictive (dosage strengths of 25, 50, 75, 100, 112, 125, 150, 175, 200, and 300 μg) formulary through a central computer system. Their 241 respective outpatients' laboratory results and drug compliance were outcome measures. Achievement of treatment objectives was measured by thyroid function tests (free and total thyroxine, total triiodothyronine, thyrotropin), number of clinic visits, and compliance (survey method). Additional measures were drug distribution patterns, drug costs, and pharmacy inventory costs. Restriction of levothyroxine's dosage strength did not significantly alter therapeutic outcomes. However, the restricted formulary was associated with more complex dosing regimens, and resulted in no significant cost savings. It is not known whether such restriction would adversely affect the care of patients of nonspecialists. Prospective studies are required to verify presumed cost-containment measures before such measures are adopted for widespread application.

Original languageEnglish
Pages (from-to)1103-1110
Number of pages8
Issue number6 I
StatePublished - Nov 1996

ASJC Scopus subject areas

  • Pharmacology (medical)


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