Stuff on weight loss, excercise, domestic abuse and bladder function. Put together by a medstudent blogger, Clinton Pong at Not my second opinion.
Patient information: over-the-counter medications
What over the counter medications should I be careful about with my kidney disease?
All over-the-counter medications have the potential to be harmful and so they should only be taken according to the labels and if you have any questions you should call you doctor. However, there are a few over-the-counters that are particularly problematic for patients with weak kidneys. Here they are:
- Ibuprofen (Advil, Motrin), Naproxen (Naprosyn)
- Sodium phosphorous solutions (Fleets enemas or fleets oral cathartics)
- Magnsesium citrate (MagCitrate)
- Pseudophedrine
Ibuprofen (Advil, Motrin), Naproxen (Naprosyn). Both of these medications are non-steroidal anti-inflammatory drugs or NSAIDs. There are a number of other NSAIDs that are prescription only including indomethacin, Celebrex and others. The problems with NSAIDs goes for all of these agents, not just the over-the-counter ones. NSAIDs block the production of prostaglandins that trigger inflammation in the body. Unfortunately, in the kidneys, prostaglandins help maintain blood flow. Blocking prostaglandins can decrease the blood flow to the kidney and cause the kidney to shut down. This is more common when patients are also taking diuretics (water pills) and blood pressure medicines called ACE inhibitors or ARBs. (Common ACE inhibitors include Vasotec, Zestril benazapril, Altace or any drug which ends with –pril. Common ARBs include Cozaar, Diovan, and Atacand or any drug which ends with –sartan.)
NSAIDs can also interfere with blood pressure medicines and cause patients to retain fluid.
Sodium phosphorous cathartics. Fleets enemas and oral solutions are used to treat constipation or prepare patients for surgery or colonoscopy. Recently we have learned that these medications can cause severe permanent kidney damage. Little is known about how often this occurs and appears to be rare but people with normal kidney function have developed severe renal failure requiring dialysis or transplant following exposure to these medications. Unfortunately not all doctors are aware of this complication and are still prescribing these medications. A clear picture of who is at risk for this complication has not emerged but experts agree on the following risk factors:
- Advanced age
- Chronic kidney disease
- Use of diuretics (water pills)
- Use of ACE inhibitors or ARBs
In addition to the risk of damaging the kidneys with sodium phosphorous, patients on dialysis who take these drugs are at risk of severe elevations in phosphorous that may kill them.
Magnesium citrate is sold under the brand names Citro-mag and Citroma. Magnesium citrate is used to treat constipation and to cleanse the bowels before surgery. In patients with severe kidney disease (CKD stage 4 and 5 and dialysis) it can cause harmful levels of magnesium.
Pseudoephedrine is the active ingredient in some cold medicines (Actifed, Sudafed) that are now kept behind the counter due to the fact that pseudoephedrine is one of the ingredients needed to manufacture methamphetamine (crystal meth). Pseudoephedrine raises the blood pressure by about one point and the heart rate by about 2 beats per minute in patients with normal blood pressure or people with well-controlled high blood pressure. This should not cause any problems. However, in patients with poorly controlled or untreated hypertension, pseudoephedrine may cause larger changes in blood pressure and should only be used after speaking with your doctor.
Patient information: Nephrogenic Fibrosing Dermopathy
Are MRIs safe for patients with kidney disease?
Sometimes. In 2000 a new skin disease was discovered that caused patients to develop thick skin around their joints, especially the knees. The thickened skin prevented people from bending their legs so they can’t walk. The disease was initially only found in patients on dialysis.The condition was named nephrogenic fibrosing dermopathy or NFD for short.
For a long time doctor’s had no idea what caused NFD. Then in 2006 some doctors in Europe noticed that only patients who received gadolinium during an MRI developed NFD. Other physicians verified this association and now it is generally accepted, though not proven, that gadolinium is at least part of the cause of NFD.
Gadolinium is used as contrast for patients receiving an MRI when doctors want a better view of the blood vessels. It is always used in a related imaging technique called an MRA. The FDA has identified people at risk of developing NFD. The list includes people with:
1. Acute renal failure
2. CKD stages 4 or 5
3. Cirrhosis induced kidney disease (called hepatorenal sndrome)
4. End-stage renal disease on dialysis
There is no proven strategy to prevent NFD except to avoid exposure to this agent. New contrast agents are being developed that do not have gadolinium. If your medical condition absolutely requires a gadolinium MRi then your doctor may schedule special dialysis sessions to remove the toxin right after MRI.
If you are on dialysis or have any of the other risk factors you should make sure your doctor knows about NFD and you should coordinate the MRI with your nephrologist.
There is no risk of NFD if you do not receive contrast with your MRI.
Patient information: Contrast nephropathy
I am writing some patient information articles to go on our SCSP’s website, scsp.net.
I am including them here as I fine tune them. I have been in contact with Dr. Shah, a nephrologist who has produced some gorgeous patient information booklets that we will be posting online also.
I have heard that getting a dye for a cardiac catheterization or CAT scan can damage my kidneys. Is that true?
Yes. X-ray dye is usually made with iodine and is sometimes called iodinated contrast. The dye allows doctors to see the blood vessels and used when using x-rays to diagnose a number of medical problems. The dye that can damage the kidneys is always given intravenously. Another type of dye is given as a oral liquid. This oral contrast is not harmful to the kidneys.
If you have healthy kidneys the IV dye is almost never harmful; however if you have weak kidneys (chronic kidney disease stage 3, 4 or 5) and especially if you also have diabetes or are also over the age of 65 you are at risk of kidney damage from the contrast.
The kidney damage is called radiocontrast nephropathy. The damage is usually temporary (7-10 days) but sometimes it can cause permanent renal failure requiring dialysis.
There are ways to reduce the risk of developing radiocontrast nephropathy, though even in expert haqnds the risk cannot be eliminated. Protective strategies include:
1. Stopping diuretics
2. Hydrating the patient with saline solution
3. Taking an anti-oxidant called N-acetyl cysteine
4. Reducing the dose of contrast
5. Using a contrast agent with less toxicityIt is important, that if you are at risk of radiocontrast nephropathy and are going to get IV contrast that you notify your nephrologist beforehand so she can coordinate the protective strategy to spare your kidneys.