Levothyroxine To Treat Low Thyroid (Hypothyroidism)
Undiagnosed thyroid disease may put you at risk for serious health conditions, such as heart diseases, osteoporosis, and infertility. Approximately 60% of individuals with thyroid disease don't even know they have it. Don't be one of them.
How Does My Thyroid Work?
Your thyroid gland is located low on the neck, below your Adam’s apple, and in front of the trachea (windpipe). The gland is shaped like a butterfly with 2 symmetrical lobes. Thyroid hormones are produced by your thyroid gland and control metabolism, as well as the systems that keep you alive, such as heart and nervous system activities, muscular strength, body temperature, skin dryness, menstrual cycles, and weight and cholesterol measurements.
Your thyroid gland produces 2 thyroid hormones known asand . Both hormones require iodine and tyrosine in order to be produced. Your thyroid gland is the only organ that can absorb iodine, which is included in T3 and T4. The production of these hormones is regulated by the thyroid-stimulating hormone (TSH) and thyrotropin.
What is Hypothyroidism?
In hypothyroidism, there is an increase in TSH and a decrease in T4 in your body. When thyroid hormones decrease, your body slows down, and the classic symptoms of low/slow metabolisms, such as weight gain and fatigue, occur.
The most common cause of hypothyroidism is Hashimoto’s disease, an autoimmune condition that consists of your own antibodies attacking your thyroid gland. Hypothyroidism may lead to depression, infertility, and/or cardiovascular disease.
The prevalence of hypothyroidism increases with age and most commonly occurs in women over the age of 60 years old.
If hypothyroidism is left untreated for an extended period, a fatal complication called Myxedema coma may occur. Myxedema coma is a life-threatening emergency depicted by poor circulation, anemia, hypothermia (abnormally low body temperature), hypometabolism (abnormally low metabolic rate), and confusion.
What are the Signs and Symptoms of Hypothyroidism?
- Cold temperature intolerance and/or sensitivity
- Dry, coarse skin and hair
- Fatigue (feeling tired)
- Muscle cramps, weakness, and/or soreness
- Voice change and become lower or hoarser
- Weight gain
- Myalgias (muscle pain)
- Bradycardia (slow heart rate)
- Hair loss
- Menorrhagia (heavier than normal menstrual periods)
- Memory and mental impairment (“brain fog”)
- Seeing physical changes in your face (including drooping eyelids, as well as puffiness in the eyes and face).
How is Hypothyroidism Diagnosed?
A diagnosis of hypothyroidism is based on 2 laboratory tests:
- Low free thyroxine (normal range 0.9–2.3 ng/dL)
- High thyroid-stimulating hormone (normal range 0.3–3 mIU/L)
Screening should be considered in individuals over the age of 60 years old. If you have any of the symptoms of hypothyroidism, talk to your healthcare provider. If your thyroid is enlarged, your doctor may be able to feel it during a physical exam during an appointment.
Watch 'Ask Marley Drug: Taking levothyroxine? Here's what you need to know.'
How is Hypothyroidism Treated?
The goal of treatment is to resolve symptoms, normalize TSH and avoid over-treatment; excessive doses of thyroid hormone will cause hyperthyroidism.
The drug of choice for hypothyroidism is levothyroxine sodium (T4). Levothyroxine is a synthetic (man-made) version of the thyroxine hormone. It replaces thyroxine when your thyroid gland cannot produce it and prevents hypothyroidism symptoms.
Synthroid is a brand name for levothyroxine sodium. Brand-name preparations are generally the first medications available on the market. After a specific amount of time, other manufacturers are allowed to make generic versions of the same drug. Although the active ingredient remains the same, the inactive ingredients used to increase absorption, conserve the medication, or provide color can vary. Generic medications may also be less expensive for you.
How is Levothyroxine Taken?
This medication is taken by mouth, once a day with water, at least 60 minutes before breakfast or at bedtime (at least 3 hours after your last meal). Levothyroxine should be taken at the same time every day.
The initial levothyroxine full replacement dose is often prescribed based on your body’s weight of 1.6 mcg/kg body weight per day, for example, 100 to 125 mcg per day for a 70 kg adult. Levothyroxine dosages range between 12.5 mcg - 300 mcg. To be sure the dose being used is optimal for you, your blood will need to be tested regularly (at least once a year).
It could take a few weeks for your body to adjust to levothyroxine. Even if you feel fine, keep taking this medicine. This medication may have to be taken for the rest of your life to replace the thyroid hormones your body cannot produce.
How Long Does It Take for Levothyroxine to Start Working?
You have to take levothyroxine for 3-5 days before it starts having an effect in your body. However, it usually takes 4-6 weeks for the medication to fully control your thyroid hormone levels. That is why your doctor usually gets you to try a certain dose for at least a month before determining if you are on the right levothyroxine dose.
References (for the onset): Lexicomp levothyroxine
Side Effect of Levothyroxine:
If you are euthyroid (have a normal functioning thyroid gland), then no side effects should exist.
If your dose is too high, you may experience hyperthyroid symptoms such as:
- Fast or irregular heartbeats
- Shortness of breath
- Fever, hot flashes, sweating
- Chest pain, pain spreading to your jaw or shoulders
- Weight loss
- Feeling hot/sweating
- Tremors, feeling nervous and/or irritable
If you experience signs or symptoms of an allergic reaction while taking levothyroxine, such as hives, difficulty breathing, swelling of your face, lips, tongue, or throat, get emergency medical help immediately.
If you forget to take a dose, take it as soon as you remember unless it's almost time for your next dose. In this case, skip the forgotten dose and take the next one at the usual time. Do not take 2 doses together to make up for a missed dose. If you take more levothyroxine than your doctor prescribes, you may experience symptoms such as a palpitation (racing heart).
What Should I Avoid When Taking Levothyroxine?
Grapefruit juice, infant soy formula, soybean flour, cottonseed meal, walnuts, and high-fiber meals are all items that can cause your body to absorb less levothyroxine.
Speak With Your Doctor
Many medications can alter the effects of levothyroxine; talk to your physician about all the medications you’re taking, including over-the-counter (OTC) drugs, vitamins, supplements, herbs, and heartburn medications.
When things in your body aren't quite right, and you can't figure out why, thyroid disorders may be to blame. Talk to your healthcare provider today and send your prescription to Marley Drug. Save up to 95% compared to your local pharmacy by using Marley Drug.