Doxycycline and how to protect the gut microbiome?

Hi,

I’m thinking of adding Doxycycline to my weekly Rapa routine. But, I’m worried about my gut microbiome. Any thought of how I can use doxycycline without hurting my little good bacteria friends?

There is some research that adding Doxycycline to Rapamycine works synergistically:

Rapamycin Plus Doxycycline Combination Affects Growth Arrest and Selective Autophagy-Dependent Cell Death in Breast Cancer Cells - PubMed (nih.gov)

“The rapamycin + doxycycline combination decreased tumour proliferation in about 2/3rd of the investigated cell lines. The continuous treatment reduced tumour growth significantly both in vivo and in vitro. The effect after short-term treatment was reversible; however, autophagic vacuoles and degrading mitochondria were detected simultaneously, and the presence of mitophagy was also observed after the long-term rapamycin + doxycycline combination treatment. The rapamycin + doxycycline combination did not cause apoptosis or necrosis/necroptosis, but the alterations in autophagy- and mitochondria-related protein levels (LC3-B-II/I, p62, MitoTracker, TOM20 and certain co-stainings) were correlated to autophagy induction and mitophagy, without mitochondria repopulation.”

However, there is concern that it would destroy (or severely impact the gut microbiome).

I found an interesting study…

Unravelling the collateral damage of antibiotics on gut bacteria | Nature

…where an antidote to the doxycyline effect on the microbiome can be induced without affecting the efficacy of the doxycycline (e.g. with benzbromarone or with another drug in their study).

Although benzbromarone comes with its own issues (e.g. Hepatocellular toxicity of benzbromarone: effects on mitochondrial function and structure - PubMed (nih.gov)

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Here is that interesting study about an antidote:

Unravelling the collateral damage of antibiotics on gut bacteria | Nature

What dose of doxycycline are you going to take?

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100mg with my 6mg rapamycin weekly. As per Peter Diamandis Longevity Protocol: Weekly 6mg Rapamycin + 100 mg Doxycycline - General - Rapamycin Longevity News

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I think it’s a bad idea to take doxycycline unless it’s to treat an infection.

Last summer, I took doxycycline for 2 weeks for a condition. After that, I developed food sensitivities that I never had before, likely a result of doxycycline killing some good bacteria that are needed to process certain foods.

Specifically, I can’t eat certain foods like potatoes, tomatoes, and peanuts anymore because I get a rash after eating them. I never had this before doxycycline. This really sucks because I like these foods.

I’m trying to rehabilitate my microbiome by taking probiotics and eating fermented foods such as kimchi, which seem to help somewhat, but I’m not back to how I was before. If you kill certain species of good bacteria, it’s very difficult to bring them back. You may never be able to.

Plus there’s always the risk of allowing the antibiotic resistant bacteria to flourish with indiscriminate antibiotic use.

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Absolutely, risk benefit is skewed. That’s why the study purporting to find drugs that act as an antidote for the gut bacteria while allowing doxycycline to be effective seemed good. In the study (Unravelling the collateral damage of antibiotics on gut bacteria | Nature) they found that certain drugs both protected the biome whilst allowing the antibacterial agent to be as effective. Just wondered if anyone knew about this approach?

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Do you remember the dose rate that you used? I’ve been thinking of this as well, but it may be a case of dosage.

You’re making me think it might not be worth it.

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I took 150mg per day for 2 weeks.

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How harmful can it be if it’s taken once a week at 100 mg?

I’m not sold on the benefits, I would like to see that IND drug application.

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How harmful can it be if it’s taken once a week at 100 mg?

I don’t know.

100 mg once per week seems so little in comparison with 150 mg/day for 2 weeks. I took doxy very recently - found a tick that was on my skin for not more than 2 hours. My dose was 100mg/twice a day for 5 days. Doesn’t look like it affected my biome. While taking doxy I had kefir and a probiotic daily (not sure it it makes any difference).

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I didn’t know it could prevent Lyme disease.
Might be handy to keep around regardless if tick country.

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Dentist’s prescribe periostat (20mg doxycycline) for long term treatment of periodontis. It is claimed that at 20mg doxycycline is submicrobial. I am thinking of taking it as a mmp-9 inhibitor.

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Doxycycline as inhibitor for mmp9
https://pubmed.ncbi.nlm.nih.gov/19200854/

Just learnt that my white blood cells count dropped significantly after just 5 days on doxycycline - from 5.06 to 3.72. Will retest in 2-3 weeks.

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During those 5 days, were you taking doxycycline daily?

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Apologies, reread your post above, which answered my question.

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I also had a pneumonia vaccine done at the same time when I started taking doxycycline. In addition, I was on Rapa. So it could be the vax that affected WBC count or combination of the three. Now it’s difficult to know what to blame.

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Doxy is a very nice drug. If caught within 24 hours, just 200 mg dosed once has been suggested to prevent Lymes.

The effect on the microbiome from regular use , however, is a whole other story. The benefit/ risk might be worth it but no one knows.

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Long-term treatment with sub-antimicrobial dose doxycycline has no antibacterial effect on intestinal flora

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