Levothyroxine and British National Formulary (BNF)

Levothyroxine and British National Formulary (BNF)

Today I got an alert about the latest edition of the BNF including significant changes from previous editions. Surprisingly it had this in the actual alert email:

BNF & BNFC update

To maximise absorption, levothyroxine sodium should preferably be taken at least 30 minutes before food, caffeine-containing drinks (e.g. tea, coffee), and other medication. For further details see levothyroxine sodium. Drug interactions for levothyroxine may be found in Appendix 1.

(BNFC is BNF for Children.)

So, all these years after various research has pointed out interactions between levothyroxine and what seems like almost anything you could consume (slight exaggeration maybe, but it feels like that), finally BNF starts to catch up. I for one do not believe that half an hour is sufficient gap but it is better than there being nothing! Might be enough for black coffee, but suspect it would not be long enough for many other foods and drinks.

Let alone supplements and other medicines.


9 Replies

  • Rod, how many years has it taken them to catch on, 30/40?

    I agree that 30 minutes isn't long enough and it's a bad omission not warning to take it 4 hours away from calcium and iron.

  • It is only six years or so since the famous coffee/ malabsorption paper was published - but other things have been known for very much longer.



  • Levo does NOT work long term!!

  • Well I have taken it for nearly 14 years and would prefer Armour as I prefer natural rather than synthetic, however it does seem to be okay for me, so there is probably no point in upsetting GP and endo on insisting I have Armour, when levo seems to do the trick.

  • That's interesting helvella, as I had a slight disagreement yesterday with a doctor (not my Doctor,) about how to take Levothyroxine and get the best uptake from it by taking it on an empty stomach and 4 hours away from iron and calcium, Doctor looked at me as if I was cuckoo, he checked his trusted bible which just said "take Levothyroxine before breakfast.

    Are Doctors sent these BNF updates ?

    I won't tell him his Bible might need updating ;)

  • When i read these responses I am just so happy I don't allow the nhs to manage my Hashimoto's or control my dosage. If only I had not been stupid enough to trust them with (mis)managing my health for so long!

  • I remember my GP saying specifically that I could take the levo any time I liked and that it didn't matter. It was 10 years ago though.

  • Interestingly I posted a while back about being interviewed by the pharmacist because I was on long term medication. The outcome of which was had I been informed the best way to take my meds and he outlined this. I said yes but didn't stress that I'd found it out myself, not from my GP!

  • That's interesting. Do you know if people find that antibiotics and NSAIDS can interract too? It doesn't list them as interracting in the patient information leaflets. Just wondered what other people have experienced?

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