Living with Psoriatic Arthritis (PsA)

Looking for some scientific stuff about stopping biologics when on antibiotics


My ‘wonderful’ abdominal issues continue sadly without abating. Following on from my rather bizarre hospital experience last week where Dr Beer Belly decided what caused my condition was a muscle strain from being overweight, I caught up with my rather excellent GP this week. I asked her about the scan results and the blood tests results from last week. Sadly there were no blood test results as the samples had deteriorated. Yes these were samples actually taken in an emergenciy room of a hospital. So Dr Beer Belly has yet failed even more, given he didn’t ask for more blood tests to be done again.

However the GP ordered some more and the CRP and ESR are exceptionally high showing that whatever is going on in my gut, it’s got an infection. So antibiotics here I come. Along with a more coherent referral to an abdo specialist which is currently being fast tracked.

I start the 7 day antibiotics today. So will obviously miss next week’s Benepali, since I take it on a Tuesday.

But for me all this doesn’t make a lot of sense. Say for example I took the Benepali Monday evening, started antibiotics Tuesday, finished antibiotics the next Monday, there would obviously be nothing stopping me taking the Benepali on Tuesday, would there? In that example I don’t lessen the effects of the biologic on the antibiotics at all, do I? And say I was on Humira which is taken only every two weeks, again I wouldn’t need to skip a dose of Humira for a seven day course of antibiotics then either. In both examples the dose of the biologic isn’t in reality reduced when taking antibiotics, is it?

So please can someone tell me why we’re told to skip doses of biologics? I understand the science of why a biologic can affect how an antibiotic works but I don’t understand the advice when in lots of situations the actual dosage of of the biologic isn’t actually affected.


Hi Poo, it sounds like you already know it’s not an interaction between the biologics and antibiotics that’s an issue - it’s the interaction between your immune system and the biologics.

Antibiotics are great, but they generally need a reasonably intact immune system alongside them in order to do their job. Whilst many of us ignore a cold, if you have an infection significant enough to require antibiotics, and particularly a highly raised ESR and CRP, then you need to stop the immune suppressants (biologic or otherwise) we take for PsA until the infection has cleared.

If you can talk to your Rheumy or rheum nurse about this, that’s the best source of advice. Don’t muck about with the risk given it sounds like an abdominal infection.

Mine has told me to wait until all symptoms, particularly fevers (even if they are low) have cleared, AND I have finished the course of antibiotics before recommencing.

In theory, we should all stop our immunosuppressants as soon as we get a serious or bacterial infection. Life is messier than that in reality, which sometimes means we keep taking it without realising what we’ve got, and yes, some of us get through that without incident. A few don’t.

Ideally (dates for demonstration), you’d be due for your (weekly) benepali Nov 1, look in your crystal ball and know you were going to get an infection Nov 7, and not take it, so that while you are fighting the infection and on antibiotics from Nov 8-15, you’d have no benepali in your system, then on 16 Nov, you’d be perfectly healthy and resume it again.

Since it doesn’t pan out that way, we just muddle through doing the best we can.


As always Jen, my issue tends to be the lack of cogency in the advice given. Back to my issues of what food to not eat when taking biologics.:rofl:

Yes I had understood the biologics affect the workings of my immune system and that for antibiotics to work, they don’t need my immune system being so affected. You expressed it far better than me, thankfully.

And since we can’t anticipate when we might get an infection we obviously plod on taking our biologic as prescribed, then obviously if told to take antibiotics, we do. But on that basis if we happen to have to take antibiotics say the day after taking our biologic the reality of that antibiotic being able to do its stuff is fairly minimal though isn’t it? It has to be, doesn’t it? Hence the lack of cogency in taking antibiotics and only skipping the ‘next’ dose of biologics. Surely it might be better to delay the taking of the antibiotic until near enough to next dose of biologic? Wouldn’t that be more rational?


Don’t think there is any evidence (wouldn’t be ethical to run a double blind study obviously). So the idea of quitting while on ABX is what I lable “anecdotal logic” It makes sense or does it? There can be a very strong case made continuing therapy is a good thing…

I always ask my rheumy (not my PCP) whether or not to quit) most times they say no on the Biologic depending on the antibiotics and yes on the MTX (again depending on the antibiotics.

The half life of biologics is so long that most courses of antibiotics are long done before the amount of active drug in your system is lowered enough to make much difference. With MTX it’s a toxicity issue.

Just ask the one doc who knows. Most rheumies get a little pissy when an outsider messes with their protocol. My local Ortho says he fears only two things his wife an Dr. Melody NXxx (rheumatologist) they are the same person, two different roles.


Well, I guess it depends how sick you are. If you are in bad shape, delaying antibiotics can lead to surgery, hospitalisation, death etc.

But on the whole you are right - it’s all a bit irrational - and as @tntlamb says, anecdotal. Just trial and error essentially. After all, what ethics committee is going to approve a double-blind placebo controlled study where you give people biologics then deliberately infect them with a range of bugs, and delay antibiotics for some :joy::joy:

Of course what ends up happening is that while you’ve got the biologic in your system AND you are taking the antibiotics, if it’s a nasty infection, it may not get better, but the hope is it won’t get worse, or if it does more slowly (after all, the biologics only impair a small part of our immune system, not knock it out). Then you may need to continue antibiotics for at least a course after the biologics has gone from your system to clear the infection. This is, for example, what happened when I got an infected cyst below the skin in my shoulder.

On the other hand, when I got Dengue Virus I had some super bizarre temperature readings, and after a lot of curious research, came to the conclusion Humira may we’ll have helped prevent really nasty effects :open_mouth:.


I work at pharmacy… so with that in mind please, be sure to discuss ALL your meds and ALL your concerns with a lic. pharm.

As I tell people every day, your doctor knows disease, your pharm knows the meds/chemicals.



It doesn’t work quite like that in the UK, azurelle. The rheumatologist prescribes the biologic and it’s then delivered to you by courier by a separate company nothing to do with ordinary pharmacists in the hgh street or indeed your GP. Your GP prescribes antibiotics which you pick up from an ordinary pharmacy. And ne’er the twain shall meet. So being able to access a pharmacist who truly understands both is hit and miss. And for me last week, even my local hospital got things wrong, which isn’t where my rheumatologist consults from either. So for this situation my local pharmacy would not be the place to discuss these issues at all. And for that matter neither would the advice line at the rheumatologist’s as they gave me the wrong advice in August about stopping the biologic and ensuring I went from a fast responder to it to a slow or non-existent responder.


Thanks @tntlamb and @Jen75. Fascinating stuff really. So I looked up Enbrel believing it rather than Benepali would have more information.

The washout period for Enbrel is 15 days. Interestingly for Humira it’s 70 days. The half life of enbrel is only 80 hours.

For me I’ve been rather unwell now with some gut issues for 13 days now and I took my dose of Benepali on day 2 and again on day 9. I sought medical care on day 4. My GP referred me directly to hospital thinking the pancreatitis or gall bladder issues. The hospital then completely effed up last week meaning it failed to ensure it did blood tests capable of a reading (the blood it took degraded and it never repeated doing a blood test). Astonishingly I got discharged on that basis too. So it wasn’t until day 11 of being ill that we realised my CRP and ESR were far too high, when my GP ordered a repeat of the blood test. And so I started antibiotics yesterday, 48 hours after the last dose of enbrel. So I’m not even at half life yet.

Obviously I’m not that seriously ill or otherwise I wouldn’t be capable of deducing any of this or even care to. I can tell you that all food seems grossly unattractive though. But considering I have weight to lose and seem very, very attracted to water, I’m presently doing OK.

So I’m now going to explain all this to my rheumy and say that I’m not intending to skip my next dose of Benepali unless they tell me to. We’ll see what happens and I’ll report back. My problem is of course that I don’t think Benepali is working. The rheumatologist in October felt I should give another 12 weeks. I said I would only give it till end of November. (I’m pretty done with endless 12 week trials, which also have a whiff of irrationality about them too) and of course I really, really don’t want to mess that up by skipping a dose now.

For me however, I’m really pleased I’ve learnt so much more about the whole thing now. As you can see I hate irrationality but I can cope with it if somewhere along the line there is at least something rational to base it on.:roll_eyes:


Yep, I know how you feel. Arbitrary rules and guidelines on someone else’s hunch just annoy me. Interesting about the very long washout for Humira - seems consistent with my experience though, where if I delayed a dose of Enbrel I knew about it in days, whereas with Humira, it seemed to be resilient to the occasional delayed dose. Though I haven’t researched it, I speculate it’s not just the biologics direct effect on the TNF, but also that a cumulative damping effect happens across the whole inflammatory cascade, and because it’s a chronic, rather than acute condition, other cytokines take a while to switch back to hyper-inflammatory mode once the biologic has been stopped, so it takes a while for the whole cascade to build up again. Now I want to Google. But too tired :zzz:

Hope those antibiotics help you shake it soon and you can go back to getting on with progress on the PsA meds. I’ll cross my fingers for you that this gut thing has been lurking for a while, and it was the presence of it dialing up your immune system that made the benepali seem ineffective second time round, so once it is gone, you and benepali can live happily for-long after :crossed_fingers: