9 Synthroid Side Effects That Might Mean Your Dosage Is Way Off

The recommended starting daily dosage of SYNTHROID in adults with primary, secondary, or tertiary hypothyroidism is based on age and comorbid cardiac conditions, as described in Table 1. For patients at risk of atrial fibrillation or patients with underlying cardiac disease, start with a lower dosage and titrate the dosage more slowly to avoid exacerbation of cardiac symptoms. Dosage titration is based on serum TSH or free-T4 see Important Considerations For Dosing. HypothyroidismSYNTHROID® (levothyroxine sodium) tablets, for oral use is indicated as a replacement therapy in primary (thyroidal), secondary (pituitary), and tertiary (hypothalamic) congenital or acquired hypothyroidism. Levothyroxine is a prescription medication that is used to treat hypothyroidism (underactive thyroid gland). Levothyroxine works by mimicking the activity of the natural hormone that is normally generated by the thyroid gland.

This includes prescription and over-the-counter medicines, vitamins, and herbal products. Tell your doctor about all your current medicines and any medicine you start or stop using. If you become pregnant while taking Synthroid, do not stop taking the medicine without your doctor’s advice. Having low thyroid hormone levels during pregnancy could harm both mother and baby.

You’ll feel better immediately after starting treatment.

The major pathway of thyroid hormone metabolism is through sequential deiodination. Approximately 80% of circulating T3 is derived from peripheral T4 by monodeiodination. The liver is the major site of degradation for both T4 and T3, with T4 deiodination also occurring at a number of additional sites, including the kidney and other tissues. Approximately 80% of the daily dose of T4 is deiodinated to yield equal amounts of T3 and reverse T3 (rT3).

General adverse events

The relative bioavailability of SYNTHROID tablets, compared to an equal nominal dose of oral levothyroxine sodium solution, is approximately 93%. T4 absorption is increased by fasting, and decreased in malabsorption syndromes and by certain foods such as soybeans. In addition, many drugs and foods affect T4 absorption see DRUG INTERACTIONS. Thyroid hormones can increase the body’s metabolism and promote weight loss.

Hormones and headaches go together like PMS and chocolate, sadly. So anytime you mess with your hormone levels you have the potential for a real headache. That said, many women find their chronic headaches improve once the Synthroid kicks in. The bump that moves is the cartilage often called the Adam’s apple, and underneath that is where your thyroid sits.

• You may not be able to take Synthroid if you have certain medical conditions.
• It may take several weeks before your body starts to respond to Synthroid.
• Providing a complete list of medications to the doctor will help with getting the correct dose established for each individual patient.
• The estimated background risk of major birth defects and miscarriage for the indicated population is unknown.
• Synthroid is prescribed in tablets that range from 25 to 300 mcg in strength and is usually taken once a day with a full glass of water (about 8 ounces) 30 to 60 minutes before breakfast for best adsorption into the body.

Converting hypothyroidism to the euthyroid state with Synthroid may increase the blood level of theophylline, and it may be necessary to change the dose of theophylline. Intravenous administration of epinephrine to patients with coronary artery disease may lead to complications ranging from difficulty in breathing to a heart attack. These complications may occur more frequently among patients also taking Synthroid. Anxiety is a fact of modern life for many women, but if you find yourself feeling seriously amped up and worried a lot, it could be a sign of an overactive thyroid and may indicate your Synthroid dosage is too high, Goldfarb says. Don’t suffer in silence; if you’re feeling unusually anxious, manic, or depressed after a few weeks on the meds, talk to your doctor.

Your menstrual cycle is one of the many things regulated by your thyroid and one of the primary signs of hypothyroidism in women is an irregular period. Going on Synthroid should actually help you return to a normal cycle, which is a good thing, but may be surprising if you’ve gotten used to missed or delayed cycles. If your cycle is still wacky after a few months on the medication, talk to your doctor, Goldfarb says. Concurrent use of tyrosine-kinase inhibitors such as imatinib may cause hypothyroidism. Concurrent use of ketamine and SYNTHROID may produce marked hypertension and tachycardia.

While most women tolerate the different generics just fine, some may have a reaction to the other ingredients used in the pills. If you’ve got a rash, fever, exhaustion, or hives, call your doctor immediately, she says. They can switch you to a different type of generic or tell the pharmacy you need to be on the brand name. The thyroid has a big effect on your weight and appetite, making you gain or lose weight rapidly. If you suddenly put on more than a few pounds, it could be a sign your meds aren’t working or the dose is too low, Goldfarb says.

• Along with its needed effects, levothyroxine (the active ingredient contained in Synthroid) may cause some unwanted effects.
• Thyroid hormones do not readily cross the placental barrier see Use In Specific Populations.
• If cardiac symptoms develop or worsen, reduce the SYNTHROID dose or withhold for one week and restart at a lower dose.
• This includes prescription and over-the-counter medicines, vitamins, and herbal products.
• Thyroid hormones, including SYNTHROID, either alone or with other therapeutic agents, should not be used for the treatment of obesity or for weight loss.

Measure and evaluate unbound (free) hormone and/or determine the free-T4 index (FT4I) in this circumstance. Pregnancy, infectious hepatitis, estrogens, estrogen-containing oral contraceptives, and acute intermittent porphyria increase TBG concentration. Nephrosis, severe hypoproteinemia, severe liver disease, acromegaly, androgens, and corticosteroids decrease TBG concentration. synthroid binders Familial hyper- or hypo-thyroxine binding globulinemias have been described, with the incidence of TBG deficiency approximating 1 in 9000. Synthroid should not be used to treat obesity or weight problems. Dangerous side effects or death can occur from the misuse of levothyroxine, especially if you are taking any other weight-loss medications or appetite suppressants.

Levothyroxine is a medication that is generally taken for life to maintain normal thyroid function. Because of the increased prevalence of cardiovascular disease among the elderly, initiate SYNTHROID at less than the full replacement dose see DOSAGE AND ADMINISTRATION and WARNINGS AND PRECAUTIONS. Atrial fibrillation is the most common of the arrhythmias observed with levothyroxine overtreatment in the elderly. Synthroid is prescribed in tablets that range from 25 to 300 mcg in strength and is usually taken once a day with a full glass of water (about 8 ounces) 30 to 60 minutes before breakfast for best adsorption into the body. Children can take the medicine if the tablet is crushed and put into about 1 to 2 teaspoons of water; do not store or delay giving this crushed pill suspension. Doctors often may have to slowly increase the dose; patients should not increase or decrease this medication themselves.