MTX and adverse interactions with other drugs

I am posting this because I was recently prescribed amoxiclav while on MTX, and while I am not allergic to penicillin and have taken amox before, this time I was horribly ill as amoxiclav does not allow the kidneys to remove MTX as usual. I did not realise this, so with each week I got worse as I diligently took my medicine and only stopped when I couldn’t think straight. My GP didn’t realise this either, as there’s been no problems with amoxiclav before (before MTX)

So do please double check any you meds against your existing ones.


GPs have to treat a lot of patients and to err is human, and unfortunately we have a daft system where half the meds are dispensed by the GP & the other by the hospital, both incurring admin costs, trying to pass the cost burden to the other, like moving money from your left pocket to the right, and right pocket thinking it saved money!

Worse still, there is no central nhs drug dispensing and interaction checking computer system, it relies on the GP and you.

Don’t let what happened to me happen to you.


  • jamieA
    jamieA Member Posts: 605

    Hi @Arthuritis

    I hope you have now recovered fully.

    Like you I've found out the disconnect between the parts of the health service I've had to be involved with in the last two and a half years with regards to prescribed drugs. In my case Rheumatology, Cardiology and my GP do not seem to communicate with each other effectively - if at all.

    Seven months after being diagnosed with PsA I was hospitalised with atrial fibrillation and tachycardia never having had a heart issue previously. The cardiologist stopped Amitriptylene immediately and then - eventually - NSAID Etodolac was stopped due to the possibility of severe stomach bleeds with blood thinners . Both had been prescribed by rheumatology. Four months later I had another tachycardia event and was hospitalised again. I didn't see the cardiologist but was seen by a rheumatology consultant who immediately halved my MTX and I've not had another instance since. Three months after that I was diagnosed with anaemia and was put onto B9, B12 and D3 suppliments to overcome this. After a bit of Dr. Google research I found out that PPIs can cause this. When I checked I found I was still prescribed omeprazole even though my NSAID had been stopped 7 months earlier. It's not particularly easy to work out what's going on when you are taking 140-150 pills a week in dosette packs made up by your pharmacist.

    In November last year I saw a cardiac consultant for a routine follow up and happened to mention my permanently cold hands and feet. He said he'd had a number of patients report the same when on the same blood thinner - Edoxaban - so he changed my blood thinner to Apixaban. Ten days after the change I started to experience severe headaches and increased tinnitus. I contacted my GP who said he'd never heard of any connection and prescribed me Gabapentin for the headaches. A month later with no change and no help from my GP other than more Gabapentin I contacted the cardiologist who recognised that my symptoms may well be being caused by the Apixiban - it's on the list of side effects - so changed me back to Edoxaban. Since my GP surgery is where my dosette box is prescribed from I had to go back to the GP who again claimed he'd never heard of this side effect and refused to change back the drug until he received a letter from the cardiologist. It took more than 2 weeks and further chasing by me to get the GP to read the letter from the cardiologist and implement the change.

    I had raised with the first cardiologist I saw the need for communication between him and my rheumatologist regarding the drug treatment I was on and he said that in an ideal world the NHS should work that way but it didn't in real life. To my knowledge there has been no communication between cardiology and rheumatology in my case.

    So I've now started to question everything.

  • stickywicket
    stickywicket Member Posts: 27,599

    @Arthuritis I'm a bit surprised you weren't told to stop your meth while on antibios. I've always done this.

    A very useful source for interactions, though (and I do believe we are wise to do our own research) is But we have to bear in mind that, sometimes, we must just take the risk. Indeed, the more meds we're on, for anything (and don't forget supplements too) the more interactions are likely. Which is why I avoid meds as much as possible😉 However, my rather large store of them is impossible to avoid now. Pain relief seem to be the only optional ones.

    If at first you don't succeed, then skydiving definitely isn't for you.
    Steven Wright
  • Arthuritis
    Arthuritis Member Posts: 412
    edited 14. Mar 2023, 23:38

    @stickywicket C’est La vie. The gp

    simply didn’t check as amoxiclav is a relatively proven safe drug, and his NHS computer prescriptions ordering system didn’t check what else I was on. Even though BNF (British National Formulary (UK drug prescribing & interaction checking bible) is part of NICE/NHS. Left hand doesn’t know what the right hand is prescribing. I am surprised you were able to post something with a .com address… I’d had so many dressing downs for posting anything with .com that I withdrew from active posting.

  • Arthuritis
    Arthuritis Member Posts: 412

    @jamieA Sadly at the time of posting I had acquired another infection and back on a/b’s but with the lessons learnt still fresh in mind.

    We live and learn. Or at least try.