Managing pain in patients with kidney disease

Pain, both acute and chronic, is commonly prevalent in patients with chronic kidney disease (CKD). This is due to the myriad diseases that often coexist in kidney disease patients (like arthritis, diabetes, obesity, etc). I had earlier written a post on how certain painkillers adversely affect the function of the kidneys. So we know that many pain medications are bad for your kidneys. We also know that even if some pain medications are not directly toxic to your kidneys, they can still accumulate in your body and affect other organs in patients who have kidney disease. It saddens me when patients with pain come to my office after being told that they can't take a particular pain medication because "their kidney numbers have worsened". Granted that could certainly happen; but not coming up with an alternative and leaving patients "marooned" is also a disservice to them. What then could be some viable options for patients with kidney disease to deal with their pain conditions?

Few human maladies affect the quality of life as much as pain does. The World Health Organization has recommended a so called "Three Step Approach" to treat escalating levels of pain in the general population:


  • Step 1: Acetaminophen (Tylenol) or Non Steroidal Anti-inflammatory Drugs (NSAIDS, like ibuprofen, Motrin, Aleve, etc)
  • Step 2: Tramadol or low potency opioids like oxycodone (eg. in Percocet), or codeine (something that is found in Tylenol #3)
  • Step 3: More powerful opioids like morphine, fentanyl, methadone, etc 


The above approach needs to be modified for patients with kidney disease. As we discussed earlier, given the damaging effects of NSAIDS on the kidneys and the risk of accumulation of some opioids in the body in patients with kidney disease, there are certain nuances that have to be kept in mind when recommending a safer pain regimen in CKD patients. 


When CKD patients want to minimize the harmful effects of some pain medications like NSAIDS on the kidneys, non-drug options like heat therapy, massage, and cryotherapy should certainly be given a shot. All pain syndromes are not the same, and depending on the situation, there could be other alternatives available to complement the initial medication. For instance, gabapentin (Neurontin) may help patients with neuropathic pain. Cyclobenzaprine (Flexeril) might work for patients with fibromyalgia. The dosages for these medications are different for patients with CKD and are best handled by your physician.  



Image courtesy of Stuart Miles/ FreeDigitalPhotos.net


IS ASPIRIN SAFE FOR PATIENTS WITH KIDNEY DISEASE?

Aspirin is also an NSAID, just like ibuprofen. However, it has certain unique effects. In general (as we discussed earlier), at this time there is no medical evidence to support that regular use of low dose aspirin (as might be recommended for patients with heart disease) is harmful, even in patients with underlying kidney disease. Of course, patients taking aspirin need to be cautious about the risk of bleeding; even more so if they have kidney disease.



ARE ALL NON-ASPIRIN NSAIDS EQUALLY HARMFUL TO THE KIDNEYS?

NSAIDS affect the kidneys in multiple ways. They can temporarily reduce the blood supply to the kidneys, and cause scarring and permanent kidney damage over the long term. They also elevate your blood pressure and cause swelling/edema. But are all NSAIDS created equally? Not really. And it is important to appreciate this fact because for some patients, nothing else might work. In that situation, it is prudent to "pick the least toxic poison". For instance, sulindac might be less toxic to the kidneys than ibuprofen. 

NSAIDS also have different durations of action in the body, and when it comes to the kidneys, shorter acting NSAIDS (like diclofenac or ibuprofen), might be safer than longer acting ones (like naproxen). 

Finally, the newer selective COX-2 inhibitors like celecoxib (Celebrex) or meloxicam (Mobic) have the same damaging effects on the kidneys, as the older non-selective NSAIDS. 



COULD YOU USE TRAMADOL (Eg. Ultram)?

Tramadol is not known to be toxic to the kidneys. But certain points still need to be kept in mind regarding this medication. Even though it might not affect the kidney function, the metabolites of tramadol could still accumulate in patients with advanced kidney disease (GFR <30), and cause respiratory depression and seizures. Hence, it should still be dosed cautiously and the lowest effective dose used on an as needed basis. 



WHICH OPIOIDS ARE RELATIVELY SAFER?

Just like tramadol, we are worried about the accumulation of opioids (eg. morphine) that could occur when taken by patients with kidney disease. Hence, we tend to prefer drugs that are not as dependent on the kidney's function for excretion from the body. These include opioids like methadone which can also be excreted in the feces in patients with kidney disease.   



MEDICAL MARIJUANA FOR KIDNEY DISEASE PATIENTS WITH PAIN?? 

I saw a patient recently in office who faces this quandary. She had tried pretty much whatever she safely could to help her pain, and now she was at a point where she was forced to chose between relieving her pain and the safety of her kidneys. Eventually, she asked me, "doc, what do you think about medical marijuana for my pain? Would that affect my kidneys?" It was a hypothetical question for any patient living in Florida but it made me realize how profound is the problem of pain management in patients with kidney disease.

Lets leave the legal and political angles out of this argument for a while and look at this strictly from a medical viewpoint. We do have some evidence out there that routine heavy marijuana use could harm the kidneys. We certainly know that synthetic marijuana (Spice, K2, etc) use has been linked with kidney damage. This is the official position of the CDC as well. On the other hand, there is also evidence that this might not necessarily be true, especially with limited use.  But that is not the point of this argument. The point is, when it comes to treating severe pain in patients with kidney disease, could medical marijuana be a safer alternative than say, ibuprofen? My answer for now: "I don't know".   


Nephrologist
Bradenton / Lakewood Ranch / Sarasota, FL


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