Liotrix is 4:1 mixture of T4 and T3 preparations made synthetically. It is used to replenish thyroid hormones in thyroid deficiency and hypothyroidism. The only brand of liotrix available in the U.S. is Thyrolar, manufactured by Forest Laboratories.[1]
Adverse effects are mainly due to overdose. Symptoms of high thyroid levels include headache, chest pain, irregular heartbeat, dyspnea, trembling, sweating, diarrhea or weight loss. The dose of the medication may need to be reduced.[2]
This medication must not be used to treat obesity because serious, even life-threatening, effects could occur.[3]