I thought "assume....could be due to genetics" expressed that it might be one of the possible causes to individual reactions.
What triggered my response wasn't so much this statement itself, which alone is quite reasonable, but rather the statement in combination with some of the followup posts.
However, looking more closely at the table in the document you referenced, the one place where Bactrim is mentioned is as a potent
inhibitor of CYP 2C9. This means that it inhibits the metabolizing of other substances that depend on CYP 2C9 - not that it's metabolized by CYP 2C9.
The metabolism of Bactrim actually appears to be fairly complex. From the prescribing information:
Sulfamethoxazole is metabolized in humans to at least 5 metabolites: the N4-acetyl-, N4-hydroxy-, 5-methylhydroxy-, N4-acetyl-5-methylhydroxy- sulfamethoxazole metabolites, and an N-glucuronide conjugate. The formulation of N4-hydroxy metabolite is mediated via CYP2C9.
Trimethoprim is metabolized in vitro to 11 different metabolites, of which, five are glutathione adducts and six are oxidative metabolites, including the major metabolites, 1- and 3-oxides and the 3- and 4-hydroxy derivatives.
It would appear from the language used that the exact enzymes used to metabolize Bactrim are not completely known, with the exception of CYP 2C9 in the formation of the N4-hydroxy metabolite. (Yes, Bactrim inhibits an enzyme that is used to form one of its metabolites. This is not unusual.)
Sorry if this was wrong, but as you notice English isn´t my native language.
Actually, I didn't notice! Your English is excellent.
I am going to one of the top Lyme docs so I trust his judgment on what to give me.
The increased incidence of serious side effects for Bactrim has not been widely published; I only became aware of them within the last few months. Bactrim has been around for forty years, and is considered to be a well-understood drug by most doctors. And the fact is that most patients do not have serious side effects when taking Bactrim; if this were not the case, Bactrim would have been pulled from the market years ago.
Even the best doctors are not omniscient, though, and certainly many (if not most) of them are unaware of the increased severity of side effects of Bactrim that have recently been uncovered. I would simply suggest that you take the materials that I referenced to your doctor, let him review them, and then discuss what the possible risks are, and what alternatives to Bactrim exist, if you think it appropriate. If you both decide that Bactrim is low risk for you, fine! I would just want to make sure that my doctor was fully informed about the risks of a drug that has been involved in many serious reactions, some of them fatal.
I will do whatever it takes to feel better at this point.
Absolutely! So would I. I'm just recommending against a path that may result in permanent damage of various sorts.
If you ever saw the list of meds I have been on in the past ten years it would blow your mind and I never had issues with any of them.
I believe I have a similar list, and I also never had issues with any of them. Until I did, which was many years into my illness. I learned the hard way, many times over, that sensitivities to drugs can arise at any time. The progression of these illnesses, unfortunately, can make many of us more sensitive to many things over time.
Everyone is different....
Most definitely. And it's quite possible that you could take Bactrim every day for the rest of your life and never have a problem. It's just hard to know in advance, which is one reason we rely on our doctors. Sometimes it helps if we furnish them with information they may not have.
...when you write "fluconazole uses the same metabolic pathway as Bactrim", does it mean that I should avoid the meds that use the same metabolic pathway?
As it has become clear that the table entry in the document that
@Helen cited refers to the inhibiting activity of Bactrim, then what I said in what you quoted is not correct. Generally, the specific members of the cytochrome P450 family that are used to metabolize a substrate are not listed, as there are often many of them, and they may not all be known. Instead, a substance is simply said to use the cytochrome P450 pathway. Although there are more than 50 enzymes in the CYP family, six of them metabolize 90% of all drugs, with the two most significant enzymes being CYP 3A4 and CYP 2D6. Therefore, when multiple drugs use the CYP pathway, they often compete for the same enzymes, thus slowing the metabolization of one or both drugs. When this occurs, the prescribing information for the affected drugs should mention it. You can also use the drug interaction checkers on sites like drugs.com.
I am allergic to many anti-fungals (like bifonazole, oralten etc.), is there a link with the bactrim allergy?
I don't know of any link. Neither of these drugs is available in the U.S., so it's hard to check for sure from here.
