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Mino/doxy interact rifabutin.

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Posted 4/1/2018 1:30 PM (GMT -5)
If minocycline is in the same class of doxy, why it's not afected by rifabutin?
Posted 4/1/2018 3:02 PM (GMT -5)
doxy+rifabutin
/www.drugs.com/interactions-check.php?drug_list=2011-0,940-506

look, if u understand how liver processes antibiotics, u realize we should all have checked our antibiotics plasma levels. rifampin makes the liver produce more CYP3A4, a chemical that oxidizes foreign small chemicals. Almost all antibiotics are small molecules and almost all are processed by CYP3A4. doxy is processed by CYP3A4 and i bet mino is also to some extent. Although there are no studies but since the chemicals are so similar... it's unlikely there is no interaction.

so my opinion is both rifabutin and rifampin make liver produce more CYP3A4 which in turn makes drugs like doxy and mino to be removed from blood faster than they are normally, thus decreasing their effectiveness.

i think that nobody bothered to study what happens for mino, so ... doctors are first worried about lawsuits and malpraxis. One obvious case that can ruin their license is administer antibiotics that are known to interact badly because there is a study about it. so they prefer the ones that still probably interact badly, but there is non study to prove it ...

sorry to make u feel even less safe than before reading my post. maybe others have better (more optimistic) explanations...
Posted 4/1/2018 3:46 PM (GMT -5)
Well, I know DS gets tested every time he starts a new regimen and now monthly for his myco and his enzymes are always okay. He is own several abx including mino and rifampin but pulses. I know it is a concern and future liver and kidney damage are a concern for sure. It has been a long road as we were told it would be, but he is so much better now than 2-3 years ago. It is so challenging to decide which path to take.
Posted 4/1/2018 6:48 PM (GMT -5)

OriolCarol said...
If minocycline is in the same class of doxy, why it's not afected by rifabutin?

Different Drugs in the same class don't always have the same side effects...or interactions.

Mino penetrates the blood/brain barrier better.


Doxy - higher risk for sun-sensitivity.
Posted 4/1/2018 9:12 PM (GMT -5)
i just got lite sun burn from mino so that is not a very good example

/www.mayoclinic.org/drugs-supplements/minocycline-oral-route/precautions/drg-20075715

Minocycline may cause your skin to be more sensitive to sunlight than it is normally. Exposure to sunlight, even for brief periods of time, may cause a skin rash, itching, redness or other discoloration of the skin, or a severe sunburn. When you begin taking this medicine:

Stay out of direct sunlight, especially between the hours of 10:00 a.m. and 3:00 p.m., if possible.
Wear protective clothing, including a hat. Also, wear sunglasses.
Apply a sunblock product that has a sun protection factor (SPF) number of at least 15. Some patients may require a product with a higher SPF number, especially if they have a fair complexion. If you have any questions about this, check with your doctor.
Apply a sunblock lipstick that has an SPF of at least 15 to protect your lips.
Do not use a sun lamp or tanning bed or booth.
If you have a severe reaction from the sun, check with your doctor.
Posted 4/2/2018 12:05 AM (GMT -5)

mpost said...
i just got lite sun burn from mino so that is not a very good example

/www.mayoclinic.org/drugs-supplements/minocycline-oral-route/precautions/drg-20075715

Minocycline may cause your skin to be more sensitive to sunlight than it is normally. Exposure to sunlight, even for brief periods of time, may cause a skin rash, itching, redness or other discoloration of the skin, or a severe sunburn. When you begin taking this medicine:

Stay out of direct sunlight, especially between the hours of 10:00 a.m. and 3:00 p.m., if possible.
Wear protective clothing, including a hat. Also, wear sunglasses.
Apply a sunblock product that has a sun protection factor (SPF) number of at least 15. Some patients may require a product with a higher SPF number, especially if they have a fair complexion. If you have any questions about this, check with your doctor.
Apply a sunblock lipstick that has an SPF of at least 15 to protect your lips.
Do not use a sun lamp or tanning bed or booth.
If you have a severe reaction from the sun, check with your doctor.

Yes I realize that you can be sun sensitive with mino too but it occurs more with doxy.
I burned very quickly (less than 20 minutes) on doxy but was fine on mino.
I’ve read others experience is similar. I am fair skinned with freckles.


Another side effect that mino has and doxy doesn’t - it can stain the teeth a grey/blue colour but it can be under the surface so cleaning may not get rid of it but doxy can stain the outer surface - more a brownish colour.
Mino can also stain the thyroid (rare)
Posted 4/2/2018 9:24 AM (GMT -5)
some more interesting reading on doxy with regard to rifampin/rifabutin.

https://academic.oup.com/jac/article/62/5/872/728221

"Doxycycline is a tetracycline derivative that is used in malaria treatment in combination with quinine to ensure cure.25,29,60 It is an inhibitor of protein synthetase by disrupting messenger RNA and transfer RNA; 80% to 95% binds to plasma proteins and is metabolized in the liver by an unknown mechanism. No metabolites have been identified to date.61 Sixty percent is excreted in the faeces and 40% in the urine. Hepatic inducers such as rifampicin, and probably rifabutin, accelerate its metabolism and influence its plasma exposure (doxycycline AUC and half-life decreased by ∼40% with rifampicin).62 However, whether drug efficacy is compromised remains unclear."
Posted 4/2/2018 2:40 PM (GMT -5)

OriolCarol said...
Then I understand that minocycline will also be affected by these two antibiotics .... it is also synthesized in the liver.

Apparently it's just doxy...from what I've read.
I plugged them into the Drug Interaction checker I use:

doxycycline rifampin
Applies to: doxycycline, rifampin
Using rifAMPin together with doxycycline may decrease the effects of doxycycline. Contact your doctor if your condition changes or if your infection worsens. If your doctor does prescribe these medications together, you may need a dose adjustment or special test to safely use both medications. It is important to tell your doctor about all other medications you use, including vitamins and herbs.


rifampin
Minocin (minocycline)

Interactions between your drugs
No results found in our database - however, this does not necessarily mean no interactions exist. Always consult with your doctor or pharmacist.

LLMD MR mentions the interaction doxy/rifampin in his Treatlyme book.
(but not mino)
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