To do or not to do Colistin?

On oxygen in Colorado and hanging out at over 12,000 feet ANYWAY

I have not updated a lot about my health recently - partly because there has been so much other cool stuff to share with you! But that doesn't mean there hasn't been sort-of a lot going on.

Let's review...  I had my back surgery on May 22. My lungs did great with the general anesthesia. I was on IVs prophylacticly (just in case) both before and after surgery.

Two weeks later, still on a lot of movement restrictions, my lungs began to decline. About four weeks after surgery, my PFTs dipped to one of their lowest points ever (33%). My oxygen sats were low and I was feeling short of breath. We did 3 weeks of IVs and my PFTs only went up to 37%. (The last few years I've averaged 40-45%, but I was actually 49% - which was super awesome - the last time I saw my pulmonary doctor before surgery.) I showed up to my 7-week surgery check-up with oxygen, which I was needing to use with exertion. This was two weeks before we were scheduled to leave on our 3-week cross-country road trip.

With exercise, I continued to slowly improve before our trip to the point that I wasn't really needing oxygen anymore to exercise. I did alright, but I needed a lot of oxygen because we spent most of our time above 5,000 feet out west. When we got back from our trip, my PFTs were at 35% - disappointing, but not too surprising considering that I was out of my regular airway clearance and exercise routine for so long.

I got back into exercising a lot, etc. and at my pulmonary appointment this past week I was at 37%. I track my PFTs at home, so I knew the number was going to be bad. My numbers had actually been improving over the last few weeks (up to slightly above 40%), but then they tanked three days before my appointment (cause could be starting on Tobi Podhaler which can be irritating.) I was on the fence about starting IVs again before my appointment, but then when my numbers fell and I started feeling less than 100%, I felt it was time to take a big risk in hopes of a big payoff.

Colistin, the antibiotic you don't want to use unless you really have to:

With cystic fibrosis, we are constantly giving sputum samples at the doctor's office that are tested against a range of antibiotics that are either sensitive (good), resistant (bad) or show intermediate sensitivity (so-so.) One of my bacteria (pseudomonas) shows intermediate sensitivity to Tobramycin (which I am usually on when I do IVs), sensitivity to Colistin and is resistant to everything else. (Caveat: just because you are resistant to things "on paper" doesn't mean they won't still work, especially if they are combined with other drugs, which can have a synergy effect.)

Colistin stopped being used in the 1970s because of it's toxicity, which is why it has such a bad reputation. (It is currently used in an inhaled form by some CF patients like me with no problem.) But now you will see why I am tempted anyway: It belongs to a class of antibiotics that my bacteria have never seen before; It is the only thing that my pseudomonas is clearly sensitive to; And it is not known to build up resistance. Also, I have not gotten a "boost" from the last few rounds of antibiotics I've done. That doesn't mean they haven't helped, but it does mean they aren't working as well as they used to. Diminishing returns, I've called it.

My doctor's fear is that - worst case - Colistin could cause irreparable kidney damage - and that, in addition to a couple of other what might be seen as strikes against me, could make me ineligible for a lung transplant down the road. There isn't reliable dosing information for Colistin. You can't check the levels like we do with Tobramycin because the levels don't correlate to toxicity. From what I've heard from other cystics who have been on it, there can be some strange neurological side effects (tingly lips, face, drunken walking) but they usually only last a few days and/or go away when the dose is lowered. I've also read about people whose kidneys do get affected by it, but the kidneys almost always bounce back.

If only there was a way to test how the kidneys might hold up...

Creatinine levels are checked at least once a week when I do Tobra. They are always fine, which means my kidneys are handling it. The problem with the creatinine blood test is that it's really a better judge of your kidneys not doing well than if they are doing well. What I mean is that your kidneys have four times the reserve of what normal people need from them. Think of that as a green thermometer (things are all good) with red at the bottom (trouble's a brewin'). You can be at any point in that green and still have normal creatinine numbers - but you don't know how close you are to that red line. These things don't matter unless you are thinking of doing something that could put serious stress on them.

Here was my doctor's idea: the 24-hour creatinine clearance test. Since I am not in immediate need of IVs, we want to take a little time and make this decision very carefully. So this weekend I am doing a 24-hour urine collection at home. This is a more accurate type of creatinine test (not normally done, but then again, Colistin isn't often done with someone who is diabetic and has already been on a good amount of Tobra in her life.) If my kidneys are operating well into the green, then we will think about trying Colistin.

I would have to be hospitalized for this, at least for the first 5 days or so. And there would be lots of blood tests. But I think you know where I stand. To me, the risk is totally worth it. I feel like I have been sitting here all summer watching my numbers dwindle, doing everything I can and seeing very little result from it. I want to preserve what I have now instead of waiting until I am in a landslide toward transplant to bust out the Colistin. If things get wonky when I try it, we will stop right away (and HOPE that there will be no long term damage.) But in my mind, we might have come upon a new go-to drug that would make me feel a lot better and might even give my lung functions a good boost.

What do you guys think?

How close are we to transplant anyway?

If you are like me, this is a question hanging in the back of your mind right now. To me, an FEV1 of 30% and lower was always the number to fear, which is why I have been quite uncomfortable hanging out in the 30s this summer. But my doctor told me yesterday that he doesn't usually recommend people for transplant evaluation until they need oxygen at rest. This was actually a big relief to me because I feel like while my numbers might be bad, my ability to do stuff without oxygen is still really good. I'd like to think that all the exercise I do helps that, but who really knows. The big fear, in my mind, continues to be that I would get a really bad infection that would plummet me quickly downward and where I sit now I don't have the reserves to handle something like that well.

Anyway, like I said, lots going on. I will keep you posted on what we decide to do.