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Levothyroxine is a medication that is generally prescribed for the treatment of hypothyroidism, a condition in which the thyroid gland does not produce a sufficient amount of hormones. The hormones released by the thyroid gland are primarily responsible for controlling metabolism and growth. Inadequate hormone levels may lead to symptoms such as weight gain, fatigue, and hair loss. Levothyroxine is a synthetic version of a naturally occurring thyroid hormone and may help restore hormones to a healthy level in order to treat hypothyroidism. Although it is generally considered safe, if proper dosage recommendations are not followed, a potentially dangerous levothyroxine overdose may occur and require immediate medical attention.
One of the most common signs that may arise and indicate a levothyroxine overdose is a sudden and abnormal change in the functioning of the heart. Angina, a condition in which the heart does not receive a sufficient amount of blood, may occur if too much of the thyroid hormone is present in the bloodstream. The main symptom of angina is usually severe pain or tightness in the chest. Taking an excess amount of the medication may also cause the heart to beat at irregular intervals, or to beat much faster than normal.
Heart function abnormalities tend to be the main signs of a levothyroxine overdose, but other symptoms may also occur that will generally require emergency medical attention. A person who has a dangerously high amount of the thyroid hormone in his or her bloodstream may have issues controlling movement, which may range from mild tremors to full seizures. An overdose may also cause vomiting, diarrhea, difficulty breathing, pain in the legs, and feelings of confusion.
Taking levothyroxine may result in certain side effects that are typically considered normal, but may be mistaken for overdose signs if a patient is not aware of the differences. The medication may cause symptoms such as changes in weight or appetite, headache, difficulty sleeping, nausea, fever, changes in menstrual flow, temporary hair loss, and abdominal pain. These side effects will usually subside on their own after regular usage of the medication, but medical attention may be necessary if the effects worsen or do not eventually go away on their own. Tremors, vomiting, and diarrhea are symptoms that may occur as both normal side effects and after an overdose, causing confusion for some patients; however, these symptoms are usually only considered potentially dangerous when also combined with the abnormal heart functioning that is often the main sign of a levothyroxine overdose.