Levothyroxine and Heart Palpitations: What Users Say

• Nat...
• Taken for 10 years or more
• March 14, 2019

Levothyroxine for Underactive Thyroid "A word of caution about levothyroxine - not all levothyroxine drugs are equal. I recently experienced a nasty episode with generic levothyroxine because the manufacturer changed the formula (replaced lactose with mannitol) which made me very sick for months (dizziness, nausea, over tiredness, chest pain, and arrhythmia). It took a while to figure out since there was no communication of a 'change' from the manufacturer. The switch to 'Tirosint' was a lifesaver! Right away, the symptoms subsided. It is so important to check the excipients (fillers). Tirosint has glycerin, water, levothyroxine, that's it! As an NTI drug (narrow therapeutic index), I would never risk the generic again. I was too sick and spent too much money with docs who couldn't find anything wrong with me! After doing research, I asked for just ask for the brand - I am so glad as it solved all of my 'issues'!"

• Sky...
• Taken for 1 to 2 years
• June 18, 2019

For Underactive Thyroid "When Dr. increases the dosage for levothyroxine, I get overly anxious, palpitations, lack of concentration, can't sleep, an overall feeling of not feeling well, faintly feeling, no energy, bloated, itchy, eye problems, irritated, confusion, feeling like crying, very emotional, and this is only taking 50mg. I felt I was dying. The moment I took half of 25mg like I was doing before, I returned to my normal self. Doctors don't care about your symptoms, they just want to go by the book, and I'm not the only one reporting this. Others like me are out there. Doctors are not listening to us."

• Paw...
• Taken for 2 to 5 years
• April 18, 2018

Levothyroxine for Hashimoto's disease "Had my thyroid removed 2 years ago. Was put on Synthroid and have felt terrible ever since. Weight gain, joint and muscle pain, blurred vision, tremors, hair loss, constipation, irregular heartbeat, stomach problems, and the list goes on. Doctor tells me my numbers are fine, and I should be put on an antidepressant. Really. That's because they don't know enough about thyroid disease and keep pushing the drugs. This drug is next to poison, but no one listens to us. We are held hostage to these doctors that don't care. Where do we turn to because we are suffering. Help!"

• Bre...
• Taken for 10 years or more
• June 21, 2016

For Underactive Thyroid "This medication is used to treat low thyroid hormone levels. I have Hashimoto's. This is an autoimmune disorder where the body attacks the thyroid until it no longer functions properly. Many people with low thyroid hormone levels have this but are not aware because doctors tend to treat with the medication rather than the whole disease. A lot of the people posting claiming side effects are actually describing side effects of LOW THYROID or HIGH THYROID! The medication is simply a replacement hormone and will not make you constipated, have brain fog, anxiety, fibromyalgia, heart palpitations, etc. unless you are taking TOO MUCH or TOO LITTLE of the hormone. A lot of the negative reviews of this medication are absolutely ridiculous!"

• LJL...
• Taken for less than 1 month
• August 8, 2020

Levothyroxine for Hashimoto's disease "This drug has many side effects that I am experiencing: labored breathing, hair loss, blurred vision, fatigue, chest pain, heart skipping beats, nausea, and insomnia. I was taking a little oblong yellow levothyroxine that worked great, but the drug store changed companies, and this pill is round and white."

• And...
• October 10, 2018

Levothyroxine for Underactive Thyroid "I have Graves' disease and took RAI (radioactive iodine (I-131)) to treat the disease, which means now I have to top up my thyroid levels. I've previously taken Levoxyl, Synthroid, and lastly Armour. I always felt miserable with Levoxyl and Synthroid, which is why for the last three years I was taking Armour. Within the last year of taking Armour, I've had terrible inflammation, joint pain, anxiety, insomnia, hair loss, dry skin, weight gain, and the list goes on. It was coincidental that I forgot to take an Armour pill and realized how in one day all my symptoms went away. The next day I took my Armour and they all returned. It was so bad that I couldn't even bend my knees. I was miserable! I've been reading about Tirosint for the last few months, and my endo was more than accommodating to let me try it. WOW! What a difference! I'm not as hungry, losing weight, no anxiety, sleeping through the night, and overall just feeling great, as I've never had thyroid issues. However, I did have some heart palpitations last night. I'm going to get my lab work done today, as I feel the dosage may be too high."

• Tin...
• January 6, 2023

Levothyroxine for Hashimoto's disease "Tirosint Sol has given a consistency in efficacy. Other 'natural' brands were always being recalled for either too little or too much thyroid. I kept having issues of heart palpitations when the other brands I was taking had too much thyroid, and other times I would be sluggish and have brain fog when there was too little. A month or two later, after the fact, I would get a notice that the batch of thyroid NP or Armor Thyroid was being recalled. It was a roller coaster. So with the Tirosint Sol, it has given me consistency, and the solution I feel is more quickly absorbed. I wish they would come out with something similar to a glucose monitor for thyroid levels so that one could monitor their thyroid hormone levels throughout the day."

• Anonymous
• Taken for less than 1 month
• March 12, 2021

Levothyroxine for Underactive Thyroid "So I have been taking Levothyroxine for the last 14-ish years. I get my script filled by Walmart, and for some reason, I started to get this brand. Since I've been taking it, I have had all the following side effects: irregular heartbeats, shortness of breath, nervousness. I actually went to the doctor, and she lowered my dose since my thyroid levels are now off. My dose was lowered from 125 to 112. I was using my older 112 from an older script and started to feel better within about a week. When I ran out, I started to take this brand at a lower dose, and within 2 days, I am back to the horrible side effects. I will not take this brand anymore... I called the pharmacist, and they are going to see if they can get my old brand back, or I will switch to another pharmacy! I will not take any more of this medication."

• Mtn...
• Taken for less than 1 month
• September 27, 2020

Levothyroxine for Hypothyroidism, After Thyroid Removal "My pharmacy switched my prescription to Euthyrox from levothyroxine, which I had been taking for 3 years with no problem. I figured it was maybe due to a supply shortage. The first day I took it, I thought something was terribly wrong with me. I had stomach cramps, heart palpitations, and a bad headache. The second day was worse. When I went to the bathroom, I felt like electricity was going up and down through my body. And another headache. This lasted all day. I decided not to take it the 3rd morning (of course, it was the weekend). I called the pharmacy and they replaced it immediately with my previous medication."

• RQa...
• Taken for 1 to 6 months
• May 2, 2021

Levothyroxine for Underactive Thyroid "This medication gave me alarming heart palpitations. I quit using it and went back to levothyroxine and it went away. Tried using Euthyrox again with the same side effects happening. Will NEVER again use Euthyrox. Worst medication I have ever taken."

• Not...
• December 11, 2020

Levothyroxine for Hashimoto's disease "Walmart switched my prescription from levothyroxine to Euthyrox about 4 months ago. I noticed that I had been feeling off for a long time but chalked it up to 2020 blues. I started having terrible heart palpitations, though, and knew something was wrong. Went to GP, and she put me on an anxiety med. I didn’t think to tell her that they switched the prescription because the pharmacist told me it was the same medication. The palpitations continued, and they got so bad that my husband started looking up reviews for everything I take, including vitamins, and found out that this drug causes heart issues. I called my doc and got it switched back. The pharmacy tried to give me Euthyrox again and said that they have to special order the levothyroxine and it costs 5x as much as it used to. This sucks."

• Ale...
• June 14, 2019

Levothyroxine for Hypothyroidism, After Thyroid Removal "I have been on a roller coaster ride for the last 3 to 4 years. Every time my levels are checked, they come back off. I had been on Levoxyl 100 for years and don’t recall having any issues. Due to a health insurance change, I was switched to levothyroxine 100 and problems started happening. On levothyroxine 100, my levels would be out of whack, and the doctors switched the dosage to 112, and I thought I was dying. Within a couple of days, my joints, back, neck, and feet would ache. I started getting palpitations, it felt like I was having a heart attack. I ended up in the ER because of a fast heart rate and heaviness and numbness on the left side of my body. Doctors thought I was having a stroke. I was switched to Syntheroid 100. 6 days on it. I have such bad pain throughout my body and joints. My legs feel as if they are swelling. I have tried Armour and immediately developed double vision and dizziness. I have stomach issues and gluten sensitivity."

• Pen...
• Taken for 1 to 6 months
• April 3, 2019

Levothyroxine for Hashimoto's disease "After nature thyroid and Armour seemed to not be working, I was put on Tirosint by my endo. I felt great the first week or so, but since then I’ve had heart palpitations, fast heart rate, swollen legs and ankles, hair falling out, and in the short 2 months I’ve been on it, I put on 13 lbs. While all these symptoms were going on, my TSH was 0.20, which meant I was very hyperthyroid."

• BJe...
• September 7, 2016

For Underactive Thyroid "I take my medicine as prescribed, first thing in the morning on an empty stomach (5:00 am). I do the regular blood test, which my doctor says my levels are 'ideal.' While the levels may be ideal, I am not. I have never felt so miserable in my life! I went to her and showed her all the side effects I was having that are listed from the pharmacy. She told me, 'Your levels are ideal.' In the 9 months I have been on Levothyroxine 0.075 MG, I am experiencing: excessive sweating, palpitations, joint pain, leg cramps, mood changes, muscle weakness, headaches, shortness of breath, my face has a tingling sensation at times, bloated, puffy around the face, lack of concentration, extreme fatigue, and huge weight gain-40 pounds! Is there something better?"

• Mis...
• August 29, 2020

Levothyroxine for Hypothyroidism, After Thyroid Removal "I was on name brand Synthroid from 2008 until 2019, my doctor switched me to Tirosint thinking that I would have less heart palpitations and better absorption. I was on 200 mcg of Synthroid, TSH was 0.01, I am now on 112 mcg of Tirosint with a TSH of 0.1. I gained a significant amount of weight, so my endo doctor added 5 mcg of T3, I have not lost any of the weight. Since starting Tirosint, my weight has increased from 116 lbs to 130-131. I exercise and move a lot and do watch what I eat, although I do allow sweets in moderation as I always have. I have also noticed an increase in hair loss, a lot of hair loss, and very dry hair, thankfully, I have thick hair, but the dryness is awful. Long story short, I don't believe Tirosint is the right medication for me as I have gained so much weight and lost a large amount of hair, even with the added T3, which didn't help to change the weight issues. I will be requesting to go back to name brand Synthroid with the added T3 to see if this helps."

• No...
• Taken for 6 months to 1 year
• December 17, 2015

For Underactive Thyroid "I have had hyperprolactinemia for many years now (pituitary issue), and earlier this year was diagnosed with hypothyroidism. Before being diagnosed with hypothyroidism, I began having difficulty maintaining my prolactin levels, suffered extreme fatigue 24/7, had vicious mood swings, and put on some weight. After finally being referred to an endocrinologist and being put on this medication, a couple of months passed, and I was finally beginning to feel like my old self again. I no longer have to nap to get through my day, my mood swings are few and far between, and I lost the weight I had previously put on. The only side effects I can list are heat intolerance, flushing, and, not that often, heart palpitations."

• Jb7...
• August 14, 2016

For Underactive Thyroid "I've been on levothyroxine for a week. I feel great! No depression, no chills, no flaky, scaly skin, and tons of energy! I was extremely tired throughout the day. Freezing, even though it's summer in Seattle. Severe dry skin to the point of embarrassment. My hair recently started to thin in my crown area. My legs had extreme cramping to the point I couldn't sleep at night. The most traumatic experience is my recent heart palpitations and dizziness, feeling fatal during each episode. Now, with all these symptoms... I decided medicine that causes hair loss outweighs the thought of dying young (39). I will post another update, seeing how it's only a week into it. So far, the most energy I've felt in years, not cold at all, and no irregular palpitations."

• Jul...
• Taken for 2 to 5 years
• July 26, 2020

Levothyroxine for Hashimoto's disease "I thought I was having a heart attack. Flushing, sweaty, feeling feverish, heart palpitations, those symptoms seem to bring on the dizziness, which led to nausea and vomiting. The worst experience of my life. Actually passed out multiple times, and this was my only medication I was taking. They actually put me on blood pressure medication, and once I stopped this medication, I no longer needed blood pressure medication."

• Mic...
• April 11, 2015

Levothyroxine for Hashimoto's disease "My Hashimoto's with a benign nodule was found after losing my twins to early delivery. Endo believes this was a missed factor in my loss. My TSH was over 4. Started on levothyroxine 100 mcg was great for 2 months, but by the third month, my blood sugars dropped, heart was racing (palpitations), body itching like the burn you feel after a workout, my hair was falling out, severe anxiety, and I was losing 2 lbs every few days (that part I didn't mind). I was insistent to check my TSH and it was 0.27, adjusted down to 88 mcg with an extra half tab once a week. My TSH is now 2.2, but I feel the depression and fatigue. Adjusting back up to 100 since it's been 3 years. At least now I know what to watch for. I no longer experience PCOS or DM 2."

• Mii...
• Taken for less than 1 month
• April 18, 2019

For Underactive Thyroid "Just started taking this medication seven days ago, and I just can’t do it anymore. I was prescribed 25 mg, but since I’ve started taking this medication, I get headaches, have high blood pressure now, and have heart palpitations. This medication has the worst effects of any medicine I’ve ever been prescribed. It’s done more bad than good. I don’t think I can wait it out."

• Dtr...
• August 17, 2016

Levothyroxine for Hashimoto's disease "Love Tirosint. My hair is back and fingernails are not broken anymore. Feel great. Was on Armour for 6 years, got hair loss and lost beautiful nails. Previous meds gave me heart palpitations and I was not able to sleep. This med is the real deal, but it's too expensive."

• Hor...
• Taken for 1 to 6 months
• December 22, 2022

Levothyroxine for Underactive Thyroid "I have been on Levothyroxine for 4 years. I recently had my prescriptions moved to, guess where.... Walmart.... and they switched me to Euthyrox. I have been feeling awful. Horrible mood swings, insomnia, sweating out of nowhere, waking up due to the fact that my heart is beating 85 bpm while sleeping and horrible heart palpitations that go on for hours. The heart palpitations have been so bad that I almost went to the emergency room. I did see my doctor yesterday, and I did ask them to do blood work and am waiting for my results this morning. My doctor wants to put me on a heart monitor for a week and do a stress test for my heart. After reading these reviews, I am certain it is this drug. I am seriously considering seeking legal counsel. The pharmacists at Walmart are just that, pharmacists. Who has given them the right to change anyone's medication without a doctor's consent?"

• TPF...
• Taken for 1 to 6 months
• April 29, 2023

Levothyroxine for Underactive Thyroid "Oh my gosh. I am so pissed after reading all this. I have been on a physical roller coaster for almost a year now. Last May, unbeknownst to me, Walmart switched me to Euthyrox from my regular levothyroxine medication, Synthroid. When questioned, I was told it was the same. Fast forward a short time, I can't get out of bed. I can't even think or carry on a conversation, literally. I have a condition that causes me fatigue, so I just figured I was having a relapse. My thyroid stimulating hormone (TSH) level had jumped to 13+. I didn't have the other normal symptoms like my skin/hair being dry and constipation, so I didn't pick up on it, it might be my thyroid or the medicine. Just in a fog, with extreme fatigue, pain, and irregular heartbeat. My doctor increased my meds. I talked to the pharmacist. I was told again that it was the same thing, but 'some' people have problems taking it. I asked if they could note it on the computer. I would have to call every month. Fast forward to almost a year later and I'm still trying to get things regulated."

• Dee...
• September 6, 2015

Levothyroxine for Hashimoto's disease "I was so excited to find this medication. I had previously been on Synthroid and its generic for over 20 years with no problems and suddenly became intolerant with debilitating side effects. We tried adding Cytomel, which caused terrible heart palpitations, and then tried Armour, also causing terrible heart palpitations and chest pain, both meds were reduced greatly with the same effect. I finally found Tirosint and did wonderfully on it for over 6 months. Then my stomach had severe issues. Through specialists and so many tests, treatments, and a whole lot of money, we finally stopped Tirosint on a whim. I'm all better stomach-wise, but out of options otherwise. Since even compounded T4 uses fillers, I have no more options."

• Pom...
• Taken for 6 months to 1 year
• April 5, 2021

Levothyroxine for Underactive Thyroid "Been on levo for 35 yrs. Started Euthyrox in May 2020 when Walmart changed meds. Pharmacist said it was the same thing, just a different manufacturer. Was fine for a while, then started feeling bad. Saw Dr in Dec 2020 for hives on my shoulders and forearms. Levels were slightly elevated but not enough for concern. Between Dec 2020 and Mar 2021, it all went south. Started having strange symptoms - sensitive skin from scalp to foot, itching, insomnia, palpitations, and weird headaches that seemed to come from nowhere, and then the rash started. Nothing put on topically helped. Changed detergent, lotion, and shower gel, and it got worse. Suspected the Euthyrox. On Mar 30, found these reviews that explained it all. Saw Dr the next day, said I was the 2nd person that day with the same problem. After doing research on my levels, in Mar 2020 my level was 3.5; in Mar 2021, the level was 23."