how long for methimazole to work?

[firefly7]

How long did it take you guys for it to kick in?   Almost three weeks ago here were my labs:
TSH                  [L]  <0.01 uIU/mL              [0.30-4.70]
Free T4                   1.89 ng/dL                  [0.75-2.00]
FT3                  [H]  5.5 pg/mL                   [2.3-4.2]  

I'm on 10mg of methimazole which I take as 5mg twice a day.   I had a slow start with it two weeks ago, taking only 5mg as I am notorious for my medication reactions but as I'm okay so far I'm gone up to 10mg for the last three days.   Still the minute my beta block leaves my system my resting heartrate zooms up to 100 or with caffeine even more.   I'm cutting out the caffeine altogether now - bums me out because chocolate is my comfort food.   My first visit with the endo isn't for a couple weeks yet.    Thanks in advance!

[firefly7]

HI Goolarra, I'm on metoprolol and it can make me feel slow, clumsy, my reaction times are seriously impacted - makes me a little nervous about driving.   I hope in time I can adapt to it like you have.    Labs won't be for another three weeks when I see the endo for the first time but I may call the doc before then if this keeps up.

[goolarra]

Okay, well, I have you both beat in the tachycardia department!  LOL  I have a WPW syndrome, and when I have an episode, my pulse is so fast that I can't count it.  My BP monitor just returns an error message.  I had an episode once in the doctor's office, and with a stethoscope, they counted 208.

Just had to throw that in...

You could also try a different beta blocker.  I take atenolol, and I do remember that slow feeling at first, but I haven't experienced it lately.

Have you noticed any improvement in symptoms at all?  

[firefly7]

WPW syndrome?   208 sounds scary fast - I hope you didn't have to go for long with it like that.    It's hard to say whether I've had any improvement or not because the beta blocker does very effectively mask the symptoms.    I've only been on the full 10mg of methimazole for less than a week though so I'm okay with giving it more time.   Feeling a tad calmer this evening....

[Red_Star]

I have Hashimoto's thyroiditis but i also have an inflammed thyroid. Well more inflammed than normal anyway.  I had a look through my health diary i started in January and noted the highest heart rate i recorded was 113bpm but i still didn't feel it. O_o  

I have had higher heart rates due to severe magnesium deficiency such as 300bpm for a few minutes and 250bpm for 7 hours.  Okay so those episodes i could feel my heart pounding so i'm not super weird (maybe) ha! but at least i could count my heart rate...yeah goolarra you win lol!

[goolarra]

Interesting about the magnesium deficiency.  How did you find out that's what was causing your tachycardia?  Do you think your Hashi's contributed?  Do you know what caused the deficiency?

I find it interesting because I haven't had a tachy episode in close to 2 years.  I've always thought that was because I finally got my thyroid under control and have been very stable.  However, I also started taking magnesium about that time, and I've wondered about that, too.

[Red_Star]

I was pretty certain magnesium deficiency was the problem.  That is once i figured out what the problem was....around 6 years after my first heart episode.  And since correcting my magnesium deficiency, almost a year ago now, i haven't had a sudden high heart rate episode since.  In my case at least, Hashi's wasn't the problem in regards to this symptom.

I eat about once a day due to a poor appetite. I'm a walking nutrient deficiency lol. So not enough magnesium in my diet is a factor. There may be other factors as well but my deficiency worsened after surgery and then prolonged high doses of vitamin D.