The only brand of liotrix available in the U.S. is Thyrolar, manufactured by Forest Laboratories.

Sometime prior to 2008 Forest Laboratories released the following statement regarding the limited availability of liotrix: "U.S. Pharmacopeia, an official public standards-setting authority for prescription and over-the-counter medicines and other health care products manufactured or sold in the United States, has mandated new specifications for a component used in the manufacturing of Thyrolar.

As a result, all strengths of Thyrolar are currently on long-term back order while modifications necessary to meet these new specifications are made.

Symptoms mimic those of hyperthyroidism and include headache, chest pain, irregular heartbeat, dyspnea, trembling, sweating, diarrhea, and weight loss.

[4] Sympathomimetic cardiovascular effects including: heart palpitations, chest pain, arrhythmia, sweating, chest pain, and anxiety, require urgent medical attention.