Get Informed: Synthroid
Active Ingredient(s)
Levothyroxine
What does it do?
This product is primarily used to treat hypothyroidism. It consists of T4, one of the important hormones produced by the thyroid gland.
- Last Text Update:
- 2009-Nov-20 9:18 PM
- Last Data Update:
- 2009-Nov-20 6:52 PM
Other Names
- Synthroid
- Levothyroxine
- Levoxyl
- Levothroid
- Unithroid
How Safe Is It?
- Your Risk Rating
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- Average Risk Rating
-
- Pregnancy Category:
- A
Black Box Warning
This product has a black box warning relating to its ineffectiveness and dangers as a weight loss treatment.
Facts & Figures
- Date Approved
- 01 Dec 1963
- Est US Patients*
- 12,390,000
- Generic Available
- Yes
- OTC Available
- No
User Age Distribution*
< 21
21-39
40-59
60+
Age (Years)
* Estimated number of US people currently taking Synthroid or its active ingredient based on population adjusted patient numbers registered with iGuard.org.
Recent alerts for Synthroid
There have been no alerts regarding Synthroid during the past year.
Synthroid Safety Report
Learn more about iGuard's risk ratings
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What is Synthroid used for?
iGuard.org is currently tracking more than 72,600 patients that use Synthroid (or similar drugs with the same active ingredient(s)). Use the table below to learn why iGuard users take this product; click on any underlined condition to get information on other medications used for treatment.
| Disease / Condition | % | Average Severity |
|---|---|---|
| Hypothyroidism | 91% | 
|
| Other | 10% |
|
How well does Synthroid work?
iGuard.org regularly polls our more than 72,600 users taking Synthroid (or similar drugs with the same active ingredient(s)) using the Treatment Satisfaction Questionnaire for Medications (TSQM) . This feedback is continuously updated in tables below for the benefit of the iGuard community. To request scores for specific patient subgroups, please contact research@iguard.org.
Average Satisfaction Score
(out of 10)
Average Effectiveness Score
(out of 10)
- 80%
- of patients are confident that the good things about Synthroid outweigh the bad things.
- 26%
- of patients wish they were told more before they started taking Synthroid.
Common Side Effects of Synthroid
iGuard.org regularly polls our more than 72,600 users taking Synthroid (or similar drugs with the same active ingredient(s)) to monitor the development and frequency of side-effects. This feedback is continuously updated in tables and graphs below for the benefit of the iGuard community.
23% of patients experience side-effects on Synthroid
5% of patients experience signifcant side-effects on Synthroid
Most Common Side Effects...
-
Fatigue
-
Hair Loss
-
Weight Gain
-
Dryness
-
= 10%
Less than 1%: Abdominal Pain, Allergic Reaction, Anxiety, Back Pain, Bleeding, Blurred Vision, Bone Loss, Bone/Joint Pain, Breathlessness, Chest Pain/Tightness, Cold Sensitivity, Constipation, Cough, Diarrhea, Dizziness, Drowsiness, Dry Hair, Dry Mouth, Elevated Glucose, Elevated Heart Rate, Fevers/Chills, Flushing, Grogginess/Confusion, Headache, High Blood Pressure, Hot Flushes, Increased Appetite, Insomnia, Itch/Rash, Light Sensitivity, Low Blood Glucose, Memory/Speech Problems, Mental Haziness, Mood/Behavior Changes, Muscle Pain/Stiffness, Nausea, Palpitations, Restlessness, Sexual Problems, Skin Problems, Sore Mouth/Throat, SUN Sensitivity, Sweating, Swelling/Edema, Temperature Sensitivity, Tremor, Weakness, Weight Loss
Global Patient Feedback for Synthroid (Levothyroxine) ( Post a comment )
Question/Comment:
After 15 years on thyroxine 50mcg, I went to an endocrinologist, ten weeks blood tests-first then half tablet for 4 weeks, then 6 weeks no tablet. As I thought it was not necessary, though nodule still meeds to be followed up
64 year old Female
Posted: 2009-11-17 05:48:57
Question/Comment:
anyone have hot head from any meds. just trying to figure why my top of the head is hot, like someone poured hot water over it. Only it is inside the head.Its a burning sensation. Lasts a few hours and increasing more and more. Told doc. but they dont know. 59 yr old lady
60 year old Female
Posted: 2009-11-10 05:05:41
iGuard.org Answer/Reply:
Approximately 1 out of 100 iGuard patients reported hot flushes as a side effect of taking levothyroxine. Although the site of the hot flushes was not specifically mentioned as occurring on top of the head, it is possible it could be a side effect caused by the drug. You should follow up with your doctor to determine the cause if the symptoms persist or worsen.
Posted: 2009-11-10 14:36:24
Question/Comment:
I've been on 25mcg of Levothyroxine for less than a week (subclinical hypothyroidism). I know to take the Levothyroxine first thing in the morning on an empty stomach, at least 30mins before breakfast. How important is it to take it the same time each day? Should I set an alarm on the weekends and take it the same time I do on work days? Also, I take Fortamet for insulin resistance/pre-diabetes. Is it possible that the Levothyroxine could be impacting my glucose readings already? Thanks.
34 year old Female
Posted: 2009-11-09 17:09:30
iGuard.org Answer/Reply:
Timing your levothyroxine at the same time each day is optimal. It is important to also take it on an empty stomach for best results as well. Over time, the levothyroxine will reach stable levels and the exact timing of your dose will not be as critical. Try to stay within a 1 to 2 hour window each day consistently. Taking it later than usual every once and a while should not be a problem.
There is a moderate possible drug interaction between your levothyroxine and your Fortamet. The levothyroxine could cause hyperglycemia - or higher blood glucose levels. You should continue to record your glucose readings and report them to your doctor in order to best manage your health.
Posted: 2009-11-10 20:55:06
Question/Comment:
I have been on Synthroid since 1989, at which time I had nuclear radiation to overcorrect a long undiagnosed case of hyperthyroidism. When it was finally diagnosed, I was down to 93lbs. and bouncing off the walls with anxiety until I would frequently faint. The specialist worked with my synthroid dosage until it was correct at 100mcg.
After relocating to another state, my new MD changed ot to generic, which is NOT the same as synthroid. Through levothyroxin, levothroid, etc. I suffered all of the above mentioned side effects ie: weight gain, fatigue, hair loss, depression, etc. as he started increasing dosages. Finally, I demanded my synthroid 100mcg. represcribed. It worked great for several years.
In 1997, I had a complete hystorectomy, which made 100 a bit much and went to 88mcg.
After losing my mom & sister to cancer, becoming disabled from work due to other physical disabilities, my synthroid has had to be increased to 125mcg so far. This is helping a lot. My MD moved out and the lady MD who replaced him saw my records and didn't rely only on the tsh. She did a complete thyroid panel, which detected what I had complained to him about-I was hypothyroid again. After dealing with it all of these years, I feel when it is too high or too low. I am feeling better now, but will have another panel done next month. She is thorough and wants to be sure not to go over. I hope this helps someone else to prevent the problems I had two years simply because I wasn't being heard and the doc relied only on tsh testing.
God bless you all.
48 year old Female
Posted: 2009-11-05 16:57:39
Question/Comment:
I’m 49. I broke my hip 1/26. By March I had RA symptoms. Ortho did labs 8/20, it’s RA. Ortho prescribed Meth Pac for pain & swelling. Luckily a Rheumy had a cancellation. I take Prednisone, Sulfasalazine & Methotrexate. I have bone density loss due to inflammation on the knuckles on the back of my right hand. X-rays were taken of my left hand & I’ll have x-rays on my coccyx Fri. due to chronic pain. Fatigue was bad. More labs. Thyroid a little low. 50mcg Synthroid & by day 3, fatigue is gone.
49 year old Female
Posted: 2009-10-27 13:00:42
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253
Patient Comments about
Synthroid