L-thyroxine, also known as levothyroxine sodium, is a prescription medication used for certain thyroid conditions. L-thyroxine is sold under the brand names of Levothroid, Levoxyl, Synthroid, Tirosint and Unithroid. If you have diabetes, L-thyroxine may affect your blood sugar. Consult your physician if you have concerns about high blood sugar while taking your thyroid medications.
Hypothyroidism
Hypothyroidism is a condition in which the body does not produce enough of the thyroid hormone. Synthetic hormones, such as L-thyroxine, may be prescribed. The thyroid, a small gland in your neck, is responsible for metabolism. Hypothyroidism can develop for a number of reasons but usually occurs because of an inflammation of the gland. Some drugs and treatments can cause hypothyroidism to develop. The condition is most common in older women. Symptoms of hypothyroidism include brittle hair and fingernails, sensitivity to cold, weight gain, muscle or joint pain, fatigue and depression.
High Blood Sugar
If you have diabetes, high blood sugar can be a severe condition. Diabetes is a chronic disease that causes high levels of sugar to be left in the blood. In healthy people, the body produces a hormone called insulin that regulates blood sugar. In diabetics, the body often has too little insulin or is resistant to the hormone. High blood sugar can cause blurry vision, increased thirst, excessive urination, fatigue, hunger and weight loss. No cure exists for diabetes, but treatment is available to manage the symptoms.
L-Thyroxine and High Blood Sugar
L-thyroxine can affect blood sugar levels in people with diabetes. Drugs.com recommends that you test your blood sugar more frequently when beginning L-thyroxine or changing doses. Be sure that your medical practitioner knows you are diabetic and follow any medical advice about your treatment. Some preliminary animal studies suggest that L-thyroxine may affect blood sugar levels even if you do not have diabetes. A 2008 study published in “American Journal of Veterinary Research” investigated the effects of levothyroxine sodium on healthy adult horses. Researchers discovered that levothyroxine sodium may cause weight loss and increased insulin resistance, but more research is needed.
Precautions
If you are taking L-thyroxine, be sure to follow the instructions on the label. L-thyroxine should be taken on an empty stomach to increase absorption. Some side effects of L-thyroxine include changes in appetite, chest pain, changes in mood, excessive sweating, headache, joint or muscle pain, rapid heartbeat, vomiting and trouble sleeping. Some people have a severe allergic reaction to the medication. If you experience a rash accompanied by swelling or difficulty breathing, seek medical attention immediately.
References
- Drugs.com: Levothyroxine Sodium
- Drugs.com: Levothyroxine
- PubMed Health; Hypothyroidism; April 2010
- PubMed Health; Diabetes; June 2011
- “American Journal of Veterinary Research”; Effects of Long-Term Oral Administration of Levothyroxine Sodium on Glucose Dynamics in Healthy Adult Horses; N. Frank et al; January 2008
- EMedTV; Precautions and Warnings With Levothyroxine; Kristi Monson; October 2009
