Hyper-sensitive to drugs & supplements: anyone know why?

And I don’t mean “why me?” specifically, I mean generally: what causes hyper-sensitivity to drugs and supplements?

For instance, after recently diagnosing me with fibromyalgia, my neurology team advised 500mg of magnesium glycinate per day. Having learned the hard way with numerous substances, I know I can be hyper-sensitive so I took only 100mg, with dinner. Thank goodness that’s all I took! I’ve had two colonoscopies in the past and suffice to say after that tiny bit of Mg I could’ve had my third. A week later, my bowels still haven’t recovered. And glycinate is touted for not causing diarrhea! So why the violent reaction?

Similarly, I take such a tiny wee amount of Gabapentin (prescribed pre-fibro diagnosis for hot flashes and night sweats)… 300mg… that my doc just laughs and says that can’t possibly be doing anything for me. But it did solve the waking-up-five-or-six-times-a-night-sweating problem (after 15 years of disrupted sleep) while a higher dose (even 500mg) makes me high as a kite, completely unable to function.

Does anyone else experience this hypersensitivity? Have you figured out why it happens?



Hi jmhilde, and a warm welcome :wave:

Hypersensitive is me written all over, and as you can read in my blog.
And yes: my CoV-jab reactions pointed me via the CFS/fibro site healthrising to MCAS. This at last also explained all my 100s of previous strong hyper-sensitivities / intolerances and helped me find supps etc. to curb the ongoing symptoms from the 3 jabs.

My hypersensitivity is in quite a different dimension to yours though:
I had a “pixie dust” phenomenon with melatonin (even 5% of a 2mg tablet zombified me), T4 (3% of a 25µg tablet is enough for major improvements in energy, but also 2 downsides) and now with CoV itself: My wife has it and is testing positive. I have much worse symptoms, but am testing negative.

Looking more closely at your med amounts, both aren’t low at all, they’re normal, as are your reactions!

100mg of elemental magnesium per each of 3 meals would be a normal dose, not a tiny dose. The max. recommended dose is 300mg/d (more for men, less for women). 500mg is way beyond that, and most people would get diarrhea from that, so I’m surprised your neurologist team even thought about it, esp. if that was for fibro, because a third of us have IBS and many of these IBS-D - it’s a pretty dangerous suggestion in my opinion. (Most vitamins are harmless when hyper-dosed, but minerals are definitely not.) Unless they meant the amount of the compound, not the element. That however would be underdosing, cos a 500mg pill of magnesium glycinate contains only 50mg of elemental magnesium (a bit above 10%).

My main idea here is to try other forms like malate or threonate. The malate form is a combination with malic acid, whilst glycine is an amino acid / neurotransmitter.

And more importantly, you did not underdose at all, that was a normal maximum dose. So you could try less. But I wouldn’t touch it any more (either), I’d go for other types, dose halved, and/or for high doses of the B-vitamins.

Similarly gabapentin: 300mg is exactly the dose recommended for hot flashes in this 2013 study: Comparison of Gabapentin with Estrogen for treatment of hot flashes in post-menopausal women - PMC confirmed here in 2020 Gabapentin for the treatment of hot flushes in menopause: a meta-analysis - PubMed
Also it’s normal for us people to react badly to gabapentin/Neurontin at any dose, same as any med. That can be “explained” by fibro.

Does that help?

Thanks, JayCS, yes, very helpful! I had read about MCAS before (amongst so many other possible diagnoses) but I will check that out again.

OK, good to know the neuro’s recommended dose of 500mg was NOT a normal dosage and, again, really glad I only took 100mg. I might’ve ended up in emergency if I’d taken that full dose, yikes!

As for the Gabapentin, yes, I’d read those same studies, so I’m puzzled why my doc says I could easily take ten times my current dosage (300mg) without repercussion. I’m thinking (again) I need some new providers. It’s always something, isn’t it?

The neuro also recommended duloxetine (which, since I have osteoporosis, may not be a good idea) as well as a visit to the pain clinic (also probably not helpful as I am so leery of taking any kind of drugs.) I’m working now on getting in to see someone at rheumatology.

Fibromyalgia is a new journey for me although I’ve been on plenty of similar, difficult-to-navigate journeys. Fingers crossed that some of the hard-earned knowledge from past experience comes in handy for this new thing. :slight_smile:

Thanks again and thanks for the warm welcome to the community!

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I’m on only 200 mg of gabapentin and I feel it’s helping. I am also super sensitive to medications and tend to have over-the-top reactions. I did find a study that showed that even low doses like mine have proven to be helpful, so I’m sticking with it. I try to keep medications down as much as possible and it’s really not helpful having a doctor say “that couldn’t possibly be enough to make a difference”.

I have also found that sometimes my tolerance is lower than others. I have asthma and allergies also (yay!) and occasionally have to take prednisone. Sometimes the tiniest dose will give me insomnia for a week and sometimes the same dose just makes my symptoms go away and doesn’t affect sleep.

Bodies are weird.


Yeah, do I know this. That actually again reminds me of the “histamine bucket” concept in MCAS. Our histamine amount is influenced by many different triggers: overall condition, stress, sleep, then more specifically food, meds/supps, environmental triggers. If my histamine ‘burning’ is high, I need to keep the histaminey foods down or decrease their influence by taking DAO beforehand. If it’s under control, I can eat quite a lot of my histaminey foods without problems. Occasionally I can get away with half a walnut without getting a ‘burnt tongue’ for a day.

Not saying either of you make the impression on me you have it, more just to share experiences so you can compare.

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Most of my family has these hypersensitivities to meds… one would think by now that drs would be familiar … i use a childs dose of cold meds, get relief , any more than the 4 y o dose keeps me awake all night…i witH my drs knowledge self regulate my meds as to tolerance…which can be half a dose or at times 1/4 dose…gets me the same result

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Me again. I’ve now had three episodes of explosive diarrhea since taking that 100mg of Mg Glycinate back on March 6th. Each episode (March 6, 23 and 25) was followed by three to five days of no BMs at all. I ended up in the ED last Friday due to severe abdominal pain. Nothing found on CT w/contrast or in blood labs. Stool sample just came back negative for bacteria/virus/pathogens. I’m at a complete loss, as is my primary provider, who is referring me to Gastro.

Can Mg cause long-lasting bowel damage? Your thoughts on that or any other idea appreciated! :slight_smile:

Hey jmhilde,

My understanding is that this can all depend on your biome, the good and bad bacteria in our gut. We need to have a balance of both good and bad bacteria to breakdown and process our dietary intake (our food/medications) but just like in a science lab, add the wrong two chemicals and the reaction can be minimal to explosive. For some people a high fibre diet can cause issues with gas and for others food allergies or intolerances can develop overtime and foods we were OK with suddenly become intolerable.

I think your referral to a gastro is a good start. A dietitian might also be an idea.

Merl from the Modsupport Team

Thanks, Merl, much appreciated! My primary says yes, even that small dose three weeks ago could still be causing trouble, but she’s not worried about anything major like bowel ischemia or edema. Here in the US our medical system is pretty sub-par, so while I await a Gastro appt. I’m reaching out to every doctor I know (even friends) seeking a specialist to review the CT scan I just had. My mother died of pancreatic cancer so I’d like to rule that out.

Hey jmhilde

Well, that’s understandable.

I’m in Australia, our health system works a bit differently, but in having a family history, the medicos here would prioritise your case. Also, here when you get scans the radiographer writes a report, you are allowed to have access to both the scans and report as they pertain to you. It maybe an idea to have your own copies of scans/reports, so you can follow up yourself.

It is my understanding that (for a fee) clinics such as the Mayo Clinic do tele-consults online. You maybe able to find a clinic that offers such tele-consults. It maybe worth investigating your options.

Merl from the Modsupport Team