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Probenecid and Sulfa Allergy.

Ema

Senior Member
Messages
4,729
Location
Midwest USA
I just visited a new doctor this past week and he has proposed cidofovir IV treatment. This antiviral med requires the use of a pre-med to protect the kidneys called Probenecid. When I look up Probenecid on some sites, it looks to be contraindicated in those with a sulfa allergy (which I have).

I told the doctor about my sulfa allergy and I've also asked two pharmacists and no one seems concerned except the person potentially having the allergic reaction (ie ME!). It's listed under sulfa drugs on Wikipedia in the "other" category.

Does anyone know anything that might help to put my mind at ease regarding the potential of Probenecid to cause issues in someone with a sulfa allergy?

Has anyone had cidofovir IVs and found them helpful?

Thanks!
Ema
 

heapsreal

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Messages
10,089
Location
australia (brisbane)
I have heard it mentioned before about probenecid protecting the kidneys but i dont really understrand it as probenecid increases the half life and concentrations in the blood of antivirals and certain antibiotics. U would think increasing the concentration and drug half life that it would put more stress on the kidneys/liver???
 

Ema

Senior Member
Messages
4,729
Location
Midwest USA
I have heard it mentioned before about probenecid protecting the kidneys but i dont really understrand it as probenecid increases the half life and concentrations in the blood of antivirals and certain antibiotics. U would think increasing the concentration and drug half life that it would put more stress on the kidneys/liver???
You would think, wouldn't you? I don't get it at all.

Probenecid also lowers uric acid levels. My uric acid levels were well below range when tested last fall so I decided to start inosine which not only increases uric acid levels but also is used for immune modulating properties. I've been taking it per the Cheney protocol. And my uric acid levels are now nicely up into range but not too high.

But I was told to stop taking the inosine (and ALL supplements!) and I am also worried that it will be dangerous to take probenecid with below range uric acid levels as I assume mine will fall below range as soon as I stop the supplement.

Ema
 

Tristen

Senior Member
Messages
638
Location
Northern Ca. USA
I just visited a new doctor this past week and he has proposed cidofovir IV treatment. This antiviral med requires the use of a pre-med to protect the kidneys called Probenecid. When I look up Probenecid on some sites, it looks to be contraindicated in those with a sulfa allergy (which I have).

I told the doctor about my sulfa allergy and I've also asked two pharmacists and no one seems concerned except the person potentially having the allergic reaction (ie ME!). It's listed under sulfa drugs on Wikipedia in the "other" category.

Does anyone know anything that might help to put my mind at ease regarding the potential of Probenecid to cause issues in someone with a sulfa allergy?

Has anyone had cidofovir IVs and found them helpful?

Thanks!
Ema

Six months into my Vistide Tx, I developed a severe allergy to Probenecid. I had no other drug allergies before this, and now still do not react to sulpha, or any other drugs. My doc said that I would have to be very careful with Sulpha drugs, but I've tried several since that with no problem. My impression after speaking with my local GP and a few pharmacists, is that probenecid is very distantly related to the sulpha family, and therefore not much of a threat.

You will be doing the IV tx in the docs office and therefore can be promptly treated if you do have an allergic reaction. You will be in a safe place, so don't worry. When I reacted, they just hit me right off with IV steroids and benedryl and put it down immediately. Next time we tried a reduced dose of the Probenecid, but I still reacted severely....so that was the end of that drug, and I did the next 6 months on Vistide without it.

Probenecid is not used just to protect the kidneys, it's also used to hold blood levels of the Vistide longer. Vistide is cleared through the kidneys quite quickly.

Yes, Vistide was very helpful for me. It brought me back from the bedbound abyss. I'm a partial responder having something like 70% recovery on the drug. But that's really hard to measure since I do still have bad PEM, but the OI and other symptoms are gone.

It seems more docs are doing the Vistide Tx now. Is this due to Dr P's talk in Paris?
 

Ema

Senior Member
Messages
4,729
Location
Midwest USA
Six months into my Vistide Tx, I developed a severe allergy to Probenecid. I had no other drug allergies before this, and now still do not react to sulpha, or any other drugs. My doc said that I would have to be very careful with Sulpha drugs, but I've tried several since that with no problem. My impression after speaking with my local GP and a few pharmacists, is that probenecid is very distantly related to the sulpha family, and therefore not much of a threat.

You will be doing the IV tx in the docs office and therefore can be promptly treated if you do have an allergic reaction. You will be in a safe place, so don't worry. When I reacted, they just hit me right off with IV steroids and benedryl and put it down immediately. Next time we tried a reduced dose of the Probenecid, but I still reacted severely....so that was the end of that drug, and I did the next 6 months on Vistide without it.

Probenecid is not used just to protect the kidneys, it's also used to hold blood levels of the Vistide longer. Vistide is cleared through the kidneys quite quickly.

Yes, Vistide was very helpful for me. It brought me back from the bedbound abyss. I'm a partial responder having something like 70% recovery on the drug. But that's really hard to measure since I do still have bad PEM, but the OI and other symptoms are gone.

It seems more docs are doing the Vistide Tx now. Is this due to Dr P's talk in Paris?

I am supposed to also pre-medicate with oral Probenecid before I go. I wonder if I should talk to them about waiting to do it until I am in the hospital infusion center. Or at least in the hospital parking lot! I hate being allergic to meds!

I'm not sure why he chose the IV cidofovir...I expected Valcyte, honestly, which would have been a LOT easier from a logistical standpoint. IVs twice a month out of state are not the easiest treatment.

Thanks for writing about your experience...that makes me feel more confident!

Ema
 

Tristen

Senior Member
Messages
638
Location
Northern Ca. USA
The Probenecid is supposed to be taken 1 hour prior to the Vistide. It has to be taken with food, so bring a lunch. They have to run 3 liters of NS total for the Tx. (this is what really protects your kidneys). One liter NS without vistide is run in first. Then when they hang bag #2, I would eat and take that first dose of Probenecid....sitting in their office with IV running. When bag #2 is about 2/3 infused, and about 1 hour after taking the Probenecid, the Vistide is added to the running NS and infused slower over another hour. Then bag # 3 is hung and infused very quickly. The remaining doses of Probenecid are taken on your own hours later, but that first dose should be taken in the docs office.....that is if they are going to follow the 3 liter NS protocol, if not, then sure wait until you get there to take it. For the later probenecid doses, just be aware of the closest medical facilities in case of a reaction. Another thought is to carry some benedryl.

ps. Make sure you have access to bathrooms for several hours after the Tx. After 3 liters of NS, gonna be lots of urinating. I had several 3 hour trips off the mountain from Tahoe in the snow, many times with chains and bumper to bumper at 25 mph. So, takin a leak along the road just wasn't possible. So, I carried a urinal in the car.....but that won't work so well for a woman. Be prepared wherever you are.

Vistide worked well for me cause of the CMV. It also put the EBV back to sleep. I hear people with HHV6 are responding too, but I don't know how well.

Best,

T
 

vli

Senior Member
Messages
653
Location
CA
I have heard it mentioned before about probenecid protecting the kidneys but i dont really understrand it as probenecid increases the half life and concentrations in the blood of antivirals and certain antibiotics. U would think increasing the concentration and drug half life that it would put more stress on the kidneys/liver???
hi heaps, does that mean the probencid gives the kidneys MORE TIME to get rid of the drug--at least that's what I understand about the half life??
 

vli

Senior Member
Messages
653
Location
CA
The Probenecid is supposed to be taken 1 hour prior to the Vistide. It has to be taken with food, so bring a lunch. They have to run 3 liters of NS total for the Tx. (this is what really protects your kidneys). One liter NS without vistide is run in first. Then when they hang bag #2, I would eat and take that first dose of Probenecid....sitting in their office with IV running. When bag #2 is about 2/3 infused, and about 1 hour after taking the Probenecid, the Vistide is added to the running NS and infused slower over another hour. Then bag # 3 is hung and infused very quickly. The remaining doses of Probenecid are taken on your own hours later, but that first dose should be taken in the docs office.....that is if they are going to follow the 3 liter NS protocol, if not, then sure wait until you get there to take it. For the later probenecid doses, just be aware of the closest medical facilities in case of a reaction. Another thought is to carry some benedryl.
hi Tristen,

I was wondering if you would happen to remember the dosages of the probenecid you took--just comparing notes? on drugs.com it says the adult "maintenance" dose for gout is 500mg every 12 hrs, so did you take 4x 125mg doses, or more?? I start in a few weeks and really am not looking forward to the probenecid after hearing about how sick it can make you. Thanks!
 

vli

Senior Member
Messages
653
Location
CA
Probenecid is not used just to protect the kidneys, it's also used to hold blood levels of the Vistide longer. Vistide is cleared through the kidneys quite quickly.
I was also thinking, since someone told me how sick probenecid made them, that taking it over three or four(?) doses may serve two purposes: like you say to keep vistide in the bloodstream longer and to help the patient tolerate the probenecid better(?). My fear is I would just throw up the probenecid if it made me too sick.
 

aquariusgirl

Senior Member
Messages
1,732
Any DR lerner patients out there who are doing IV vistide?
I asked his office about the insurance coverage .. and they more or less said they let Walgreeen's take care of it. I guess Walgreens is involved in suppling the IV vistide somehow.
Not v. reassuring.
 

vli

Senior Member
Messages
653
Location
CA
when i was making enquiries a few mos ago I found that you COULD get generic IV cidofovir as opposed to the brand name Vistide that Gilead makes. This makes me wonder whether Dr Lerner is using generic cidofovir, especially since that was what Ema called it in her first post. However, I would imagine there to be a big difference in price between the brand and generic cidofovir--or am I wrong? If the two are similar in price, it begs the question of why anyone would bother to get the generic??
 

Ema

Senior Member
Messages
4,729
Location
Midwest USA
The directions on the 500 mg Probenecid read:

Take 4 tabs 3 hours before infusion, 2 tabs 2 hours after, and 2 more tabs after infusion as directed.

Very clear as always.

It's those first 4 tabs I'm worried about. I'd rather take, say, 1 tab at the infusion center to make sure I wasn't allergic before taking all 4 at once!

As far as the IV, the script read for cidofovir, so I would guess that it is the generic and not the brand name. But hopefully I will know more tomorrow as the person who deals with setting it all up was not in today.

Ema
 

Tristen

Senior Member
Messages
638
Location
Northern Ca. USA
hi Tristen,

I was wondering if you would happen to remember the dosages of the probenecid you took--just comparing notes? on drugs.com it says the adult "maintenance" dose for gout is 500mg every 12 hrs, so did you take 4x 125mg doses, or more?? I start in a few weeks and really am not looking forward to the probenecid after hearing about how sick it can make you. Thanks!

Sorry don't recall for sure on the dosages of Probenecid. But possibly we followed the protocol given by Gilead for Vistide administration, which should include Probenecid dosages.
 

Tristen

Senior Member
Messages
638
Location
Northern Ca. USA
Any DR lerner patients out there who are doing IV vistide?
I asked his office about the insurance coverage .. and they more or less said they let Walgreeen's take care of it. I guess Walgreens is involved in suppling the IV vistide somehow.
Not v. reassuring.

Yea, it comes in vials just needing NS for reconstitution. I got all my vials of Vistide from Walgreens. 25 total over all of 2009. Expensive stuff, but my insurance covered it. I prefer to support local small business's, but Walgreens worked best allowing me to pick it up in any of the several cities I would pass through on the way to my destination at Dr P's.
 

aquariusgirl

Senior Member
Messages
1,732
Just heard from my ID doc. Said he would never use vistide in a CFS patient. said he used in AIDS patients and some of them went into renal failure. Hmm.
 

vli

Senior Member
Messages
653
Location
CA
aquarius--so did you just tell him about the Peterson patients/study?
 

vli

Senior Member
Messages
653
Location
CA
The directions on the 500 mg Probenecid read:

Take 4 tabs 3 hours before infusion, 2 tabs 2 hours after, and 2 more tabs after infusion as directed.

Very clear as always.

It's those first 4 tabs I'm worried about. I'd rather take, say, 1 tab at the infusion center to make sure I wasn't allergic before taking all 4 at once!
Then it sounds like Lerner's protocol gives FAR MORE probenecid than Peterson's does, because Tristen wrote he only took one dose before he was infused with vistide.

Also, Lerner's protocol means EIGHT tabs of probenecid that day. That's 4g, twice as much as drugs.com says is the maximum for a day!!
http://www.drugs.com/dosage/probenecid.html#Usual_Adult_Dose_for_Gout

Ema: would you happen to know now whether that's because Lerner wants to be cautious (taking so much)? Perhaps you could point out that drugs.com says 2g is the daily maximum and also that another patient told you they only took the first dose after they had run in the saline and even then it was not 4 tabs??
 

Ema

Senior Member
Messages
4,729
Location
Midwest USA
Any DR lerner patients out there who are doing IV vistide?
I asked his office about the insurance coverage .. and they more or less said they let Walgreeen's take care of it. I guess Walgreens is involved in suppling the IV vistide somehow.
Not v. reassuring.
The infusions are given at Beaumont Hospital. I called there and gave them my insurance info and she is checking on it and will get back to me. She didn't know if Medicare would cover them. She did say that Dr L has been sending over orders for these "by the handful" recently starting about 2 months ago. So apparently he has changed his protocol in the not so distant past.

I have not heard anything about Walgreen's. I find it hard to believe they wouldn't just use the hospital pharmacy but nothing truly surprises me anymore.

I've also asked the nurse about the probenecid dosage and she says it is OK as it is not ongoing. I guess that is a max daily dose if you are taking it daily for gout. Im going to check and see if I can find the recommended dosage on the Vistide site too. She is also going to double check on the cross reactivity possibility with sulfa drugs.

I'll keep you all posted as I learn things!
 

Tristen

Senior Member
Messages
638
Location
Northern Ca. USA
Medi-Care paid it's 80% on all my clinic visit costs involved with having the IV Vistide Tx. That was a pretty good chunk of change figuring each visit was ~6 hours of IV Tx and supplies, times 25 infusions over that year. My Part D paid for the Vistide, but it was apparent to me that getting the full coverage (which I did), especially for that long, would require a very astute doc knowing how to justify it's off label use like that.