Maximum Carbimazole Dose?

just heard from another person on a group her Endocrinologist told her to take 12x20mg Carbimazole, she did for 3 days before questioning it. I have written on here before about 60mg and I know some on other group have had 80mg, but surely 240mg is insane? Think he must have been thinking about PTU on this one, but it does go to show how even a well educated highly paid person sometimes does not even check the details before giving meds!

9 Replies


I don't think I've heard of anyone taking more than 40mg Carbimazole. 240mg certainly seems to be a very high dose.

Just trying to fathom how such a mistake could have been made. Lime Pharma Ltd (look to be part of Actavis) say this on their Summary of Product Characteristics document:

Adults and elderly: The usual starting dose for adults is one to three 20mg tablets or four to twelve 5mg tablets.

For someone who is challenged in their reading, or arithmetic, it is just about possible to imagine lifting the word "twelve" but entirely missing the fact this applies to 5 milligram tablets.

This is in no way to be regarded as any form of excuse or exculpation.

Thanks Helvella can only assume they were thinking of PTU whilst giving instructions for Carbimazole! just does not add up

Except that PTU is in 50 milligram tablets...

wow never had that but have heard others do instead carbimazole. Going to be 'one of those things' just hope her liver coped, mine would have not for sure! So lets say we are talking of PTU then 12x50=600 so it that a safe dose?

For Propylthiouracil:

4.2 Posology and method of administration

Adults and elderly:

Initially 300 to 600mg daily, once daily or in divided doses until the patient becomes euthyroid.

When the condition is controlled (usually after 1-2 months), the dose is reduced to 50 to 150mg daily and continued for 1-2 years.

But 12 x 20 milligrams makes no sense for either medicine. :-(

thanks for the education helvella, nice to know. So many things do not make sense when we hear what some Doctors or Endo's do and say from around the country, the FB site I am a member of is a constant weekly running catalogue of amazing things said and done! I was the person who was told by my Doctor that my eyes would be last to go (meaning back) after Graves without being referred! We can only wonder what they must be thinking or not!

Thanks Clutter I have written on here few months back about me taking 60mg for 2 weeks due to low white blood count and then to 40 and now to 20. Some on FB site have taken 80mg but not sure why so high, 60mg was enough for me!

thankfully she 'only' took for 3 days then questioned it and was told not to take anymore for 3 days. I was shocked and appalled, as have had liver function problems myself on 60mg and 40mg. Thyroid communities are great because we can spread the word quickly to new people. Another young lady was told by her GP she could not give her meds for confirmed overactive thyroid only if it was under!!!

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