Keflex/Cephalexin

Medical topics with questions, information and discussion related to Lyme disease and other tick-borne diseases.
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ChronicLyme19
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Re: Keflex/Cephalexin

Post by ChronicLyme19 » Fri 9 Jan 2015 22:16

I'm sure I was definitely reacting to something, it aggravated all the nerves in my body, and was inflammatory in some nature given it felt like I had a concussion but ten times worse. For me it's not so much pain, unless my spine gets out of place from my muscles not holding.

Got a second option today from the immunologist at Mt. Sinai. She also agrees with the two LLMDs and the other local immunologist that it WASN'T a reaction to the Keflex itself. They don't have a skin test specifically for Keflex, and she doesn't think it's worth doing the skin test for penicillin. Reasons given were:
-No trouble breathing or anaphylactic shock/throat issues
-No rashes or hives (didn't think my arm getting red form scratching it meant anything)
-Wasn't itchy
-I've never had problems with penicillins or other cephalosporins
-None of the usual drug reaction stuff

Thinks it's more likely it was either the Lyme or some other infection that caused triggering the response. Could be there's just something really weird about me and Keflex, but then you'd think I'd have similar reactions to other cephalosporins. If my body was on high alert from a second infection, it could have also attacked the lyme indiscriminately. Although I don't think it was just that, because it seemed to flare the worst after I took my meds and a large meal.

Still waiting on the rest of the docs to confer with each other. At this point I'm not sure we'll be able to tell. They could always try putting me back on it without GSE and see if it's the same, but then it's still the question of what is causing the reaction, a herx or the drug itself.
Half of what you are taught is incorrect, but which half? What if there's another half missing?

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ChronicLyme19
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Re: Keflex/Cephalexin

Post by ChronicLyme19 » Fri 9 Jan 2015 22:19

And yes, I did see the "Failure of treatment with cephalexin for Lyme disease" study. But if you read the other study I posted, I do think Keflex can kill lyme but in much higher concentrations than you'd usually get orally, hence why in that study it would have failed. I still think if you had a high enough concentration it would probably kill Lyme.
Half of what you are taught is incorrect, but which half? What if there's another half missing?

RitaA
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Re: Keflex/Cephalexin

Post by RitaA » Fri 9 Jan 2015 23:57

The real question is whether you had a high enough concentration of cephalexin in your body to trigger a herx-like reaction.

Now that you've discontinued the Keflex, are your symptoms subsiding?

velvetmagnetta
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Re: Keflex/Cephalexin

Post by velvetmagnetta » Sat 10 Jan 2015 2:28

Like RitaA asked, are you OK now, ChronicLyme19?

In my totally non-medical opinion, you are most likely going through something related to Lyme or a co-infection as opposed to an allergic reaction. I hope you're alright now!! Please be cautious about going back on something that caused so many problems!

All the the pain and discomfort that has been associated with Herxing for years now may be due to something Lyme-related but completely different from a reaction to a bacterial die-off. Not enough is known about Lyme its relation to the Herxheimer effect to justify risking possible further bodily harm.

I know you want to get better really really badly, but please, just be careful and think it through before you go back into that line of therapy.

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ChronicLyme19
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Re: Keflex/Cephalexin

Post by ChronicLyme19 » Sun 11 Jan 2015 0:05

Yes, I'm back to my normal baseline with abx. Feeling good, minus the remaining back/nerve disfuction in the spinal accessory nerve and lack of endurance. It was definately Keflex that triggered everything, as the day I stopped it all the symptoms started fading. But the odd thing is, those abx with Keflex = scary symptom flare, or no abx at all = nasty symptom flare. We're all still scratcing our heads as to what to try next. For now back to standard doryx + rifampin and let my body rest.

I'm going to see what else I can dig up on the effects of rifampin and GSE on absorpton of other abx/cephalosporins, to see how probable that could be. It certainly seems plausible, but is it likely? I'm not sure.

The only other weird thing is my MCH went back into the normal range for the second time in four years. It was always normal pre-tick bite and went abnormal shortly afterwards. Normal MCH usually corresponds to me feeling great, which now that I've been off the Keflex, I do. Last time this happened, felt great, MCH went normal, went off abx and crashed. So....?
Half of what you are taught is incorrect, but which half? What if there's another half missing?

velvetmagnetta
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Re: Keflex/Cephalexin

Post by velvetmagnetta » Sun 11 Jan 2015 18:07

I so am relieved to hear you felt better after stopping Keflex. I was afraid for you because in my experience, the pain did not stop once I discontinued the offending antibiotic.

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ChronicLyme19
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Re: Keflex/Cephalexin

Post by ChronicLyme19 » Mon 12 Jan 2015 20:59

Ok, so from Wikipedia (I know, I know terrible source, but I had to start someplace):

http://en.wikipedia.org/wiki/Grapefruit_seed_extract
Grapefruit juice inhibits CYP3A4, the cytochrome P450 isoenzyme most often involved in drug metabolism.
Grapefruit juice also inhibits several other cytochrome P450 isoenzymes, but they are less frequently implicated in interactions with clinical consequences.
Longer grapefruit drug interaction list here:
http://en.wikipedia.org/wiki/Grapefruit ... teractions

If you try and see if there are interactions between cephalexin and CYP3A4, you don't come across much except:

Effect of cefixime and cefdinir, oral cephalosporins, on cytochrome P450 activities in human hepatic microsomes.
Biol Pharm Bull. 2004 Jan;27(1):97-9.
Niwa T1, Shiraga T, Hashimoto T, Kagayama A.
http://www.ncbi.nlm.nih.gov/pubmed/14709907
These results suggest that both cefixime and cefdinir would not cause clinically significant interactions with other drugs, which are metabolized by CYPs, via the inhibition of metabolism.
So it least seems maybe inhibition of CYPs by cephalexin may not be likely? I don't know enough to know if you can conclude that if they are the same class, but then that doesn't touch the other cytochrome P450 isoenzymes either. It looks like it may still be possible that GSE increases your adsorption of keflex, but then at the same time rifampin could have the opposite effect:

http://en.wikipedia.org/wiki/Rifampicin
Rifampicin is an inducer of many enzymes of the cytochrome P450 superfamily, including CYP2B6, CYP2C8, CYP2C9, CYP2C19, CYP3A4, CYP3A5, and CYP3A7.[31] Thus it will speed up the metabolism of any drug metabolized by any of these enzymes in the body.
Unless I find studies showing how both GSE and rifampin change your metabolism, it may be hard to know if I was absorbing more Keflex without repeating the combo and taking serum levels. But for now based on that one study, it does seem Keflex kills Lyme if you could get enough of it into you, so a herx may have been possible.
Half of what you are taught is incorrect, but which half? What if there's another half missing?

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