Tell your doctor if you have any of the following symptoms while you are taking levothyroxine: chest pain, rapid or irregular heartbeat or pulse, uncontrollable shaking of a part of the body, nervousness, anxiety, irritability, difficulty falling asleep or staying asleep, shortness of breath, or excessive sweating.
It's one of the most common medications in the U.S. Common side effects of levothyroxine include heat intolerance, a fast heart rate, and diarrhea.
The common clinical signs following thyroxine overdose can either be limited to tachycardia, agitation, nervousness, insomnia, anxiety, tremor [2], or severe features, though less likely, like thyroid storm involving cardiac, neurological, respiratory and thermoregulatory center [3].
The IgE mediated immediate reaction most commonly manifests as urticarial rash within minutes to hours, whereas the T-cell mediated delayed reaction usually occurs several days to weeks after exposure. Other hypersensitivity reactions to levothyroxine include angioedema, eczematiform skin eruptions, and pruritus.
Sometimes, overmedication symptoms can paradoxically be the same as those you experience when you have low thyroid hormones. These symptoms may include exhaustion, achiness, and weight gain despite feeling jittery and nervous. Some people even describe their symptoms as flu-like.
Taking too much levothyroxine may affect your heart, especially if you are elderly or have heart disease. Tell your doctor immediately if you have any signs of increased heart rate, chest pain, or an irregular heartbeat.
However, if you start noticing symptoms like anxiety, fuzzy memory, diarrhea, heart palpitations or excessive sweating, this may be a sign that your underactive thyroid is being overtreated. If your thyroid gland is underactive — a condition called hypothyroidism — your body produces too little thyroid hormone.
Levothyroxine does not usually have any side effects, because the tablets simply replace a missing hormone. Side effects usually only occur if you're taking too much levothyroxine. This can cause problems including sweating, chest pain, headaches, diarrhoea and being sick.
Cardiovascular damage may also be a side effect of levothyroxine. Signs of a heart attack like shortness of breath and chest pain, signs of heart failure like extreme tiredness and swelling in the legs, irregular heart rhythm, or a very fast heartbeat should all be taken seriously—get emergency medical treatment.
This week, the FDA announced that 27 lots of levothyroxine sodium oral solution, used for hypothyroidism, were being recalled due to potentially being subpotent. The FDA announced that pharmaceutical company IBSA Pharma recalled 27 lots of levothyroxine sodium (TIROSINT-SOL) oral solution due to sub-potency.
Yes, it's safe to take levothyroxine for a long time, even many years. However, high doses of levothyroxine over a long time can sometimes cause weakening of the bones (osteoporosis). This should not happen if you are on the right dose. It's important to have regular blood tests to make sure your dose is not too high.
You may feel nervous, moody, weak, or tired. Your hands may shake, your heart may beat fast, or you may have problems breathing. You may be sweaty or have warm, red, itchy skin. You may have more bowel movements than usual.
Thyroid hormone affects virtually every organ system in the body, including the heart, CNS, autonomic nervous system, bone, GI, and metabolism.
On February 1, 2023, the FDA announced a consumer-level recall of 27 lots of IBSA Pharma's TIROSINT-SOL (levothyroxine sodium) oral solution because these lots may be subpotent. The company's analyses show a slight decrease below 95.0% of its labeled amount in levothyroxine sodium (T4) for some lots.
Levothyroxine is a common treatment for hypothyroidism, but if your dose is too high, it can directly lead to anxiety and cause symptoms like rapid heartbeat and shakiness, which can make anxiety worse, says Rosenfeld.
If you stop your thyroid medication abruptly, symptoms of hypothyroidism will likely return. If hypothyroidism is left untreated, it can lead to serious health problems. You may experience mood swings, irritability, and slowed thoughts. In fact, hypothyroidism is one of the reversible causes of dementia.
One of the main concerns with starting levothyroxine replacement is the precipitation of myocardial ischemia or arrhythmias, which, although rare, are known to occur.
Never increase or decrease the levothyroxine dose without talking with your health care provider. Over-replacement of T4 can cause mild hyperthyroidism, with the associated risks of atrial fibrillation (irregular heartbeat) and, possibly, accelerated bone loss (osteoporosis).
Other potential thyroid medication side effects are less common, but in most cases they're caused by excessive doses of thyroid hormone. You should contact your doctor if you experience any of the following: Increased sweating. Mood swings/irritability.
Thyroid Hormone Replacement
Other medications are also available, namely liothyronine, a synthetic version of another thyroid hormone called triiodothronine (T3); liotrix, a synthetic combination of T4 and T3; and desiccated natural thyroid (natural thyroid hormone prepared from dried porcine [pig] thyroid).
Start monitoring your symptoms. “In most situations, symptoms will not change for 2 to 3 weeks,” says King. “That's important to know, because you might not feel much different for a while,” he says.
It is not unusual to have an emotional reaction before, during, or after treatment. Do talk to your doctor to check your thyroid medication is properly balanced. Finding a support group or talking with a British Thyroid Foundation volunteer can help you through this period.
When you start levothyroxine you won't feel better the next day. You may not feel better in two weeks. But symptoms should start disappearing within a month. After six weeks of treatment, you should be almost completely free of symptoms, assuming you're at the right medication level.
You're noticing skin changes
Skin changes can be signs that your treatment needs an adjustment. Very dry skin — especially your hands, elbows, and feet — can be a sign that you are not getting enough thyroid hormone when you are hypothyroid.