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EspañolTirosint overview
BRAND NAMES:
Tirosint, Tirosint-Sol, Synthroid, Unithroid, Euthyrox, Levoxyl
Generic Names:
Levothyroxine sodium
Uses:
Treats:
Hypothyroidism (the body does not produce enough thyroid hormone)
An enlarged thyroid gland
Thyroid cancer
What is Tirosint used for?
Tirosint is a synthetic thyroid hormone that is used to treat an underactive thyroid gland (hypothyroidism). It is chemically identical to the natural thyroid hormone thyroxine (T4). Tirosint’s active ingredient is levothyroxine sodium; its inactive ingredients are gelatin, glycerin, and water. Manufactured by Institut Biochimique SA (IBSA) in Switzerland, Tirosint capsules differ from levothyroxine tablets because of their dosage formulations.
Tell your prescribing healthcare provider about any other prescription drugs or over-the-counter supplements that you take or medical conditions that you have, especially heart disease or adrenal insufficiency.
Tirosint should be taken by mouth in the morning on an empty stomach with a full glass of water 30 minutes to one hour before food or other medications.
Calcium carbonate and ferrous sulfate (iron) may reduce the effectiveness of Tirosint. Take Tirosint four hours before or after calcium-containing products or iron. If you take a multivitamin, you may have to adjust when you take it so that it does not interfere with Tirosint.
It may take weeks before you notice that Tirosint is working. Keep taking it, and do not abruptly stop taking it.
Tirosint may cause symptoms of hyperthyroidism, such as irregular or increased heart rate, weight loss, sweating, and hyperactivity. Speak to your provider about any symptoms you are experiencing. The dosages may need to be adjusted a few times before finding the best daily dose for each person.
What form(s) does Tirosint come in
Capsule
13 mcg
25 mcg
50 mcg
75 mcg
88 mcg
100 mcg
112 mcg
125 mcg
137 mcg
150 mcg
175 mcg
200 mcg
What are common Tirosint doses?
Dosing of Tirosint depends on a variety of factors, such as age, weight, cardiovascular status, medications taken, or other conditions present. Dosing is usually titrated until thyroid function and thyroid hormone levels, TSH and T4, return to normal.
For healthy, non-elderly adults who have only had hypothyroidism for a few months or shorter, full replacement dosing is recommended:
Starting dose: 1.6 mcg per kg per day
Adjust the daily dose by 13 mcg to 25 mcg every four to six weeks until thyroid hormone levels return to normal
Standard dosing: 25 mcg to 200 mcg once per day
For patients who have severe or long-standing hypothyroidism, dosing will be lower than the standard dosing:
Starting dose: 13 mcg to 25 mcg per day
Adjust the daily dose by 13 mcg to 25 mcg every two to four weeks until thyroid hormone levels return to normal
For older patients or those with underlying cardiac disease, dosing will also be lower than the standard dosing:
Starting dose: 13 mcg to 25 mcg per day
Adjust the daily dose by 13 mcg to 25 mcg every six to eight weeks until thyroid hormone levels return to normal
Common Tirosint prescriptions
Tirosint
30 capsules, 75 mcg 3 blisters of 10 capsulesTirosint
28 capsules boxTirosint
30 capsules, 100 mcg boxTirosint
30 capsules, 112 mcg boxTirosint
30 capsules, 125 mcg boxTirosint
30 capsules, 13 mcg boxTirosint
30 capsules, 137 mcg boxTirosint
30 capsules, 150 mcg boxTirosint
30 capsules, 175 mcg boxTirosint
30 capsules, 200 mcg boxTirosint
30 capsules, 25 mcg boxTirosint
30 capsules, 50 mcg boxTirosint
30 capsules, 75 mcg boxTirosint
30 capsules, 88 mcg box
How to take Tirosint
Take your medicine as directed.
Your doctor will tell you how much to take and how often.
Your dose may need to be changed several times to find what works best for you.
You may have to take this medicine for four to eight weeks before your symptoms start to get better.
Take this medicine in the morning on an empty stomach, at least 30 to 60 minutes before eating breakfast.
Take your medicine at the same time every day.
Swallow whole. Do not cut, chew, or crush it.
Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light.
Keep all medicine out of the reach of children. Never share your medicine with anyone.
Do not stop taking this medicine without first checking with your doctor. You may need to take smaller and smaller doses before completely stopping the medicine.
Read and follow the patient instructions that come with this medicine. Talk to your doctor or pharmacist if you have any questions.
What to do if you miss a dose of Tirosint
Take the missed dose as soon as possible.
Skip the missed dose if it is almost time for your next scheduled dose.
You should never take two doses at the same time.
Tirosint contraindications
Do not use Tirosint if:
You have had an allergic reaction to levothyroxine or glycerol
You have an uncorrected adrenal gland problem
You have a cardiac condition
Tirosint warnings
Tell your doctor if you are pregnant or breastfeeding.
Tell your doctor if you have recently received radiation treatment with iodine.
Check with your doctor before taking this medicine if you have:
Heart or blood vessel disease
High blood pressure
Diabetes
Kidney disease
Liver disease
Anemia
Blood clotting problems
Osteoporosis
Pituitary gland problems
Adrenal gland problems
This medicine may cause the following problems:
Heart problems, including angina (chest pain)and arrhythmias
Low bone density
This medicine should not be used to treat obesity or as part of a treatment plan for a weight control program.
Tell any doctor or dentist who treats you that you are taking this medicine.
Your doctor will do lab tests at regular visits to check on the effects of this medicine. Keep all appointments.
Do not stop using this medicine suddenly. Your doctor will need to slowly decrease your dose before you stop it completely.
Tirosint interactions
Some foods and medicines can affect how levothyroxine works. Tell your doctor if you are taking any of the following:
Amiodarone
Asparaginase
Carbamazepine
Clofibrate
Dexamethasone
Digoxin
5-fluorouracil
Furosemide
Heroin
Imatinib
Ketamine
Methadone
Mitotane
Nicotinic acid
Phenobarbital
Phenytoin
Rifampin
Tamoxifen
Beta-blockers
Birth control pills (including estrogen)
Blood thinners (including heparin and warfarin)
Insulin or diabetes medicine
Antidepressants (including amitriptyline and maprotiline)
NSAIDs
Salicylates
Steroids (including dexamethasone, androgens, and anabolic steroids)
Products used for colds, asthma, appetite control, hay fever, or sinus problems
In order to lessen the impact of drug interactions with Tirosint, take the following medications at least four hours before or four hours after you take Tirosint:
Kayexalate
Lanthanum
Orlistat
Sevelamer
Sucralfate
Antacids (including aluminum or magnesium hydroxide and simethicone)
Medicine to lower cholesterol (including cholestyramine, colesevelam and colestipol)
Stomach medicine (proton pump inhibitors, such as lansoprazole, omeprazole, and pantoprazole)
Any medicine that contains calcium or iron
Cottonseed meal, dietary fiber, soybean flour (infant formula), or walnuts may decrease the absorption of this medicine. Talk with your doctor if you have questions.
Do not eat grapefruit or drink grapefruit juice while you are using this medicine.
Tirosint side effects
Tirosint has some possible side effects. Fortunately, most of them are able to be resolved by lowering the daily dose of Tirosint. However, there are a few side effects that warrant a visit to a healthcare provider. Seek medical help right away if you experience an allergic reaction, trouble breathing, severe chest pain, or swelling of the face, tongue, or legs. Talk to your doctor if you experience any other side effects of Tirosint, especially if you notice any heart irregularities.
Serious side effects:
Seizures or tremors
Fast, pounding, or irregular heartbeat
Allergic reaction: Itching or hives, swelling in your face or hands, swelling or tingling in your mouth or throat, chest tightness, trouble breathing
Chest pain that may spread
Trouble breathing
Unusual sweating
Fainting
Confusion
Swelling of the face, tongue, or lower legs
Feeling cold
Unusual tiredness or weakness
Dizziness or lightheadedness
Stomach pain
Walking with a limp from knee or hip pain (in children)
Severe headache, blurred or double vision, nausea, or vomiting (in children)
Less serious side effects:
Hair loss
Appetite or weight changes
Diarrhea
Changes in your menstrual periods
Muscle weakness or spasm
Trouble sleeping
Nervousness
Heat intolerance
These are not all of Tirosint’s side effects. Call your healthcare provider for medical advice about side effects. You can also report side effects to the FDA at 1-800-FDA-1088, as well as www.fda.gov/medwatch. This will help the manufacturer, and FDA follow any patterns of side effects of Tirosint and see if any new ones arise.
Sources:
Highlights of prescribing information, Akrimax Pharmaceuticals (2017)