[Once-weekly intravenous L-thyroxine replacement in hypothyroidism].

A 58-year-old female patient with gastrointestinal complications also had primary hypothyroidism which proved therapy-resistant against high-dosage oral replacement with L-thyroxine or an L-thyroxine/L-triiodothyronine combination. Administration of four intravenous injections each of 2 mg L-thyroxine given at weekly intervals brought about a clinical and chemical euthyroid state. Thereafter it was possible to adopt an oral L-thyroxine replacement procedure without complications. Intravenous replacement of L-thyroxine and later transfer to oral medication appears a superior and safer method than the daily subcutaneous or intramuscular administration described hitherto.