BobAug14Q. I’m in my 23rd year as a T9 para. I manage my bladder with intermittent catheterization, drink plenty of water and cath at least four or five times a day to make sure my bladder doesn’t get too full. I rarely had problems with bladder infections until recently. Over the past few years it seems like I’m fighting one after another. I try to flush them by drinking extra water, but more often than not, I end up on a course of antibiotics, which messes with my gut.

In a previous Para/Medic you wrote about an antibiotic called Neosporin G.U. that goes directly into the bladder and can be used on a daily basis. A friend’s urologist has him on a similar system, but it’s a mixture of saline and Gentamicin — he says it has kept UTIs at bay. Does one solution work better than another? And if you use them regularly, do they contribute to antibiotic resistance?

— Jeff

A. Good questions, Jeff. This is a topic that appears quite a bit on SCI-related sites, including CareCure Forum and, which discuss a myriad of solutions that can be added via catheter to the bladder to help reduce UTIs. The solutions can be added during clean intermittent catheterization (CIC) by way of a 60cc syringe that fits into the end of the catheter, or in the case of a suprapubic catheter or indwelling Foley, adding the solution and clamping the catheter for 20 minutes.

To track down answers, I turned to Dr. Michael Kennelly, director of urology at Carolinas Rehab in Charlotte, N.C. Kennelly explained that although “irrigant” is the common term for solutions that go into the bladder, for the most part they are “instilled” — that is, added to the bladder for a period of time — usually until the next catheterization if you are cathing intermittently.

For the scope of this article, I will focus on some of the most common irrigant solutions — saline, acetic acid mixed with saline, Neosporin G.U. (neomycin/polymyxin B) mixed with saline, and gentamicin mixed with saline.

Saline is an irrigant that many wheelers, including myself, were introduced to in rehab. We were taught to add 30cc of saline after each cathing — a time-consuming practice that often faded when we went out the rehab door. Kennelly explains the theory with saline is that it addresses residual urine as well as sediment left in the bladder after a CIC. Residual urine has minerals that will start to crystalize and form stones, which can cause a UTI. Adding saline should help dilute residual urine and sediment and help prevent stones and stop bacteria from colonizing. This is a good reminder to try and empty as much urine as possible when cathing. Because the sphincter is at the bottom of the bladder, it’s best to cath in an upright position, and when urine stops coming out, pull the catheter out slowly. This moves drainage eyes (holes in the end of the catheter) lower in the bladder and lets more urine flow out. For SP and Foley users, your catheter should be flushed with saline to help keep it clear.

Another option that gets a lot of mention on SCI forums is adding distilled white vinegar mixed with saline to the bladder. This supposedly creates an acidic environment that is hostile for bacteria. Kennelly emphasizes that it is important to have a discussion with your doctor before trying any irrigant solutions, and the vinegar-saline solution is a good case in point. He says the solution can irritate the bladder and cause inflammation, which weakens the bladder wall’s defense mechanism and makes the bladder more susceptible to infections.

What Studies and Docs Say
The only FDA-approved solution for bladder irrigation is Neosporin G.U. irrigant, an antibiotic solution that is mixed with saline. I learned about the mixture five years ago from Paula Wagner, my urology nurse practitioner at U.C. Davis Medical Center in Sacramento, Calif. I had been getting frequent UTIs and wanted to get away from strong oral antibiotics that were wreaking havoc on my stomach. Wagner explained that although it is an antibiotic, Neosporin G.U. doesn’t get absorbed systemically, so I can use it as often as twice a day if my urine looks bad, or once every couple of days when things are good. It reduced my UTIs from one every couple of months to less than one a year. Wagner says at U.C. Davis they tried transitioning a couple of people from Neosporin G.U. to straight saline, but they came down with UTIs. says that Neosporin G.U. should only be used for 10 days. However, Wagner says it is OK for long term use if you are consulting your doctor.

Although there are anecdotal reports of success from irrigation with acetic acid, Neosporin G.U. irrigant, and saline, Kennelly points out that hard science is less enthusiastic — specifically a study on neurogenic bladder published in the 2006 Journal of Spinal Cord Medicine that followed 89 people. Some were using indwelling catheters; others used SP or indwelling Foleys. Participants were divided into groups of 30, 30 and 29, and each group instilled Neosporin G.U., acetic acid, and saline, respectively, twice a day for 20 minutes. Based on 52 people who finished the study, results showed no problems with side effects, but also no improvement in reduction of UTIs. Importantly, the paper said more studies should be done on these options, and the studies should consider incorporating increased or more volume of irrigant, more frequency of installation and/or duration of treatment. It will also be interesting to see a study that looks at these options in CIC users.

Kennelly says, “The study doesn’t mean ‘stop things like G.U. irrigant,’ because for some people it is effective. Some of my patients irrigate with Neosporin G.U. or gentamicin, but most just use saline for irrigation to keep the SP or Foley clear.”

A paper that reviewed a number of smaller studies, published in the December 2010 International Journal of Antimicrobial Agents, reported better results with Neosporin G.U. Of four controlled studies using neomycin (Neosporin G.U.) or Kanamycin, two demonstrated a significant reduction in bacteriuria (bacteria in urine) and two did not. And three case studies of gentamicin showed a significant reduction in UTIs and bacteriuria with no relevant side effects. Wagner says that gentamicin works well as an irrigant solution for people with UTIs that are resistant to other antibiotics. She says there is lots of literature on gentamicin, especially for use in augmented bladders.

Kennelly adds that irrigant solutions are really effective when someone has a UTI and the urine sample culture tests for something that is sensitive to Neosporin G.U. or gentamicin, or another antibiotic that can mix as an irrigant. “That is great because we can avoid an oral antibiotic and put the antibiotic directly into the bladder.”

“You can be doing everything right and still have problematic infections,” says Wagner. “When this happens, it is important to talk with your urologist and ask them if an irrigant solution like Neosporin G.U., or gentamicin, is an option you should try. The bottom line is you need to do something to control UTIs, and different things work for different people.”

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