Synthroid is a synthetic version of a naturally occurring thyroid hormone. It is used medically to treat hypothyroidism and users have taken it to manage obesity or lose weight in bodybuilding. Patients with certain pre-existing conditions should not take Synthroid as its use can lead to a number of detrimental side effects, including overdose and death.
Synthroid (levothyroxine sodium) is a pharmaceutically produced synthetic version of the naturally occurring thyroid hormone thyroxine.
According to the pharmaceutical information website drugs.com, Synthroid use is indicated for patients of all ages (including children and infants) with low natural levels of thyroid hormone (hypothyroidism) caused by thyroid malfunction or atrophy, injury or damage to the pituitary gland or hypothalamus, surgery, radiation or the effects of other drugs. Synthroid can also be used to treat patients suffering from thyroid cancer, those who have had their thyroid surgically removed or patients with a goiter (swelling of the thyroid).
In healthy patients, thyroxine acts to stimulate and regulate the metabolism of fats, carbohydrates and vitamins. It affects protein synthesis, and interacts with human growth hormone to regulate bone growth. Almost every cell in the body is affected by thyroid hormones; because of this, patients with a deficiency of this hormone can experience abnormal metabolism and development.
According to the drug information site rxlist.com, late onset thyroxine deficiency in adults can produce mildly detrimental metabolic effects that include fatigue, depression, poor muscle tone, brittle nails and hair, weight gain and dry skin. A chronic deficiency can result in severe metabolic defects that lead to hair loss, anemia, irritability, decreased libido, low body temperature, menstrual irregularities, impaired memory and cognitive function, sluggishness, lowered heart rate and the constant need for sleep. Synthroid usually produces an alleviation of these symptoms after several weeks of treatment; however, some patients must take this drug for the remainder of their lives.
Bodybuilding.com reports that many bodybuilders use thyroid hormones to burn excess body fat during the late stages of contest preparation, and the author goes so far as to call thyroid hormones an “almost unmissable aid in contest preparation.” High dosages of Synthroid will enable users to burn off calories and fat, and bodybuilding.com recommends that recreational users or bodybuilders cycle their use of thyroid hormones for three weeks on and three off.
However, medicinenet.com reports that Synthroid is not approved for use in treating obesity or for managing weight or promoting weight loss. Their site further recommends users against using Synthroid for any of those purposes, and warns against combining Synthroid with any diet or other weight loss medication or supplement. Users who fail to heed these warnings may suffer toxic effects or overdose as a result.
Synthroid can aggravate certain pre-existing conditions and is not recommended for use by any individual who has recently suffered a heart attack, who has coronary artery disease, clotting problems, osteoporosis or impaired pituitary or adrenal function.
Additionally, patients taking anticoagulants, blood thinners, cholesterol medications, amphetamines, asthma medicine or diabetics taking insulin should consult a physician before using Synthroid, as these drugs will affect its activity.
Patients receiving Synthroid for hypothyroidism receive dosages partly adjusted by age and body weight. For instance, an adult less than 50 weighing 150 lbs. might take 100 to 125 mcg of Synthroid daily.
Users seeking to lose weight or manage obesity with Synthroid can overdose and may experience life-threatening symptoms that include coma, heart failure, low blood sugar and fever. These symptoms will present anywhere from 6 hours to 11 days after taking improper dosages of Synthroid.
Drugs.com reports that Synthroid has caused allergic reactions that range from hives, itching, flushing and swelling of the face and mouth to chest pain and labored breathing. Patients have reported experiencing side effects that include edema (swelling of legs and ankles), clumsiness, coldness, lethargy, menstrual dysfunction, moodiness, weakness, irregular heartbeat, insomnia, headache, changes in appetite and weight loss or weight gain.
Long-term use of Synthroid can deplete bone mass and possibly cause osteoporosis.