Thyroid UK

Liothyronine and ranitidine


I am currently taking 75mcg levothyroxine and 2x 10 mcg of liothyronine. I pregnant and suffering from reflux so have been prescribed ranitidine to help manage the acid. I am also taking two kinds of anti-emetics as I have been suffering from severe nausea and vomiting.

Can anyone help me with the timings?

I take levo/ liothyronine around 6am along with the anti emetics

I've been taking ranitidine at aroun 8am.

I take second does if liothyronine at 2ish along with second does of anti emetics

Finally I take a pregnancy vitamin with dinner and the second ranitidine at 18:00.

Do I need an bigger gap between my thyroid meds and ranitidine? I feel exhausted but am having a very difficult pregnancy so that isn't too surprising.

4 Replies

Tealtension, Congratulations on your pregnancy but I am sorry you are feeling so sick.

2 hours between Ranitidine and thyroid meds should be enough. If you can, leave 2 hours between the anti-emetic and thyroid meds too.


I am not a medical professional and this information is not intended to be a substitute for medical guidance from your own doctor. Please check with your personal physician before applying any of these suggestions.


Thank you


Hi Tealtension, have you tried eating smaller regular meals, cutting down on anything fatty? Have you tried having extra pillows to sleep more upright? Pregnancy sickness is horrible, I really sympathise, I had it all the way through with 4 pregnancies. Not sure what antiemetic you're on but what worked well for me was Avomine. Have you tried sipping skimmed milk for acid reflux?

I was on a similar antihistamine, cimetidine, for 13 years, my pharmacist told me it affected thyroid med absorption. I take it for a bladder disease, but I have weaned myself off it now and increased the other drug I take for my bladder. I got very anaemic and low vitamin B 12 on cimetidine, but I was on it for a very long time. The good thing about ranitidine is it doesn't hang around in your liver and alter enzymes.


I'm on stemitil and ondansatron for hyperemesis. I am far to nauseous to eat much other than crackers and toast so sipping milk is a no-go. I'm hopeful I get some respite soon as I'm 19 weeks.


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