Could anyone answer my question please

Hi I was wondering if anyone can help . I am on Rebif 44 and i think i have a Urine infection i am in agony can i take Trimethoprim for this as i have some which the Doctor gave me before i went on Rebif. I am not sure if there are any interactions with the Drugs .


This is the place to check to be sure, but I think it will be fine - I’ve never heard of antibiotics and Rebif interacting anyway.

Karen x

Hi Anon,

Really you shouldn’t have any antibiotics left over from last time as you are supposed to finish the full course… however…

NO is the short answer, you should not take the Trimethoprim for these symptoms as you don’t have a full course available for one and therefore will be running the risk of allowing the bug to gain immunity to the antibiotic and secondly you don’t know for absolute sure that you do have a UTI.

Make a GPs appointment, get a proper diagnosis and get a proper prescription and if it is for antibiotics be sure to finish the FULL course this time. Antibiotics aren’t supposed to be taken just until you feel better but right up until the very last tablet is finished (no left overs!!)

Hope you feel better soon,


FWIW The BNF does not list any interaction between Rebif and Trimethoprim in the copy I have.


You could always call the rebif support line just to check. Mysupport uk number- 0800 783 4660.

Alternately speak to gp or ms nurse.

Hope you feel better soon.

Teresa. x

Hello Anon,

I had been prescribed Trimethroprim 400mg per day to treat my urine infection and after this didn’t work, I was given a double strength dose of Cefalexin tablets which seems to have knocked this on the head. I have some tablets left, but even if this infection restarts I won’t be taking it. It seems much better to visit your GP as only the full course is any good and it is always better to have a qualified medic on your side. Good luck with this infection.

Best Wishes,