Levothyroxine (L-T4) should remain as the standard of care for treating hypothyroidism, according to a new hypothyroidism guidelines released by the American Thyroid Association (ATA).

“Our guidelines offer reassurance to physicians and their patients [that] no changes are needed in the current standard of care for hypothyroidism in the majority of patients,” said Dr. Jacqueline Jonklaas, chair of the task force that reviewed the latest clinical data on hypothyroidism therapeutics and an associate professor at Georgetown University Medical Center in Washington, DC, US.

The taskforce was convened to determine whether the current standard of care for hypothyroidism should be revised, and if warranted, to identify potential therapeutic alternatives to L-T4 monotherapy. [Thyroid 2014;doi:10.1089/thy.2014.0028]

L-T4 is a synthetic form of the hormone thyroxine (T4) that is converted to triiodothyronine (T3) in the body. While L-T4 is effective in most patients, some feel unwell when taking the drug, which is a cause for concern among physicians.

Although some studies suggested combination therapies may be a valid approach for patients with hypothyroidism, the taskforce concluded there was no robust evidence to recommend a change in the current standard of care.

“We found no consistently strong evidence for the superiority of alternative preparations [eg, levothyroxine-liothyronine combination therapy, or thyroid extract therapy] over monotherapy with L-T4 in improving health outcomes. However, some patients, particularly those with a polymorphism or genetic variation in the deiodinase enzyme that converts L-T4 [to T3], may benefit from combination treatments,” Jonklaas said.

Future research, she said, should focus on the development of superior biomarkers of euthyroidism to supplement thyroid stimulating hormone (TSH) measurements, mechanistic research on serum T3 levels (including effects of age and disease status, relationship with tissue concentrations, and potential therapeutic targeting), and clinical trials evaluating the long-term effects of different combination therapies or thyroid extracts.

Dr. Hossein Gharib, ATA president and professor of medicine at the Mayo Clinic College of Medicine in Rochester, Minnesota, US said while some questions remain unanswered, the new guidelines provide useful up-to-date information for endocrinologists and physicians on who to treat, why to treat, including subclinical disease, and how to treat hypothyroidism.

Pharmacists for their part can encourage patients to adhere with their medication unless advised otherwise by their physician and to report any adverse effects associated with excessive amounts of thyroid hormone such as palpitations, rapid weight loss, restlessness, sweating, and insomnia.