We've had prednisone prescribed for a lot of different conditions during our many years of pet cohabitation: from skin rashes to allergies to cancer. But this year is the first time that I've ever questioned its potential for side effects.

Rio was prescribed prednisone during her chemotherapy regimen two years ago. The purpose was to minimize the side effects of a potentially toxic chemo drug. Pred was supposed to speed healing to the tissues, and to help alleviate inflammation and pain. Last fall, before this most recent round of cancer drama, I started noticing Rio's hair was thinning. I chalked it up to aging, although she really didn't seem like she was having much else in the way of "old dog" symptoms. Not much in the way of joint pain or weight gain, although when she laid down, she looked a little bloated. She also seemed hungrier than normal, and was occasionally wetting the bed. As we went into winter, the hair loss became more noticeable — to the point where I bought her a fleecy to keep her warm when she went outside. You could see skin through her hair.

When we finally got brave/scared enough to go to the doctor's for "the" lump in January, I asked them about thyroid disorders or other causes behind Rio's hair loss. We did a full blood and urine work-up, and her numbers came back with some anomalies. Her alkaline phosphatase was sky-high and her cholesterol, triglycerides and microalbuminuria were high as well, and her T4s were low. She also had an elevated pH in her urine. While none of these findings screamed Cushing's, they indicated enough of a system imbalance to do some additional testing. We did a creatinine/cortisol ratio test to check for elevated cortisol, and followed it up by an ACTH stimulation test. By this time, we were already into our chemotherapy regimen (see our blog for more details about this). I had questioned the use of prednisone during Rio's chemo, because we were pretty sure that she did have Cushing's, but our oncologist thought that the risks outweighed the benefits. She said she'd never had issues giving Cushingoid cancer dogs Pred in the past.

Cushing's is one of those diseases that is kinda tricky to nail down. It can be caused by a benign tumor in the pituitary gland, by a cancerous tumor in the adrenal glands, or by overusing steriods such as Prednisone. There are a number of tests to determine Cushing's, however many of them simply rule out other causes, rather than a definitive diagnosis. However, when Rio's skin started developing raised bumps and peeling off in sheets, we took a few punch biopsy samples and the diagnosis was clear — calcinosis cutis — calcium and other mineral deposits in the skin — a side effect of only one known disease. At that point, although Rio's numbers were still borderline for Cushings, we went with the theory "walks like a duck, quacks like a duck, must be a duck." (Although we haven't truly nailed down the source of Rio's Cushings, we believe that it is originating in her pituitary gland.)

We immediately stopped using the Prednisone (usually you do a taper-off, but under doctor's orders, we just stopped) and started Rio on a drug called Trilostane. Within weeks, her hair started growing back. Where she had been shaved for her surgery, her hair had completely fallen out from the roots (she looked like a ham), but within just a couple of months on the Trilostane, her hair returned, soft and downy at first, but then completely filling in. Because Rio isn't just dealing with Cushing's, but also battling metastatic cancer, her internist wants to keep her cortisol levels higher than in a normal Cushings-only situation. This should help with her overall mobility, joint health and pain management, not to mention the pulmonary inflammation she's recently developed. Unfortunately, this also means that her patches of calcinosis cutis will likely never go away.

While I can't definitively point at Prednisone as being the cause of Rio's Cushings, as it is a relatively common malady in older dogs, I can say that the Pred definitely made it worse. She went from being this beauty, from having a silky-soft, glossy black and brindle coat to having naked, crusty, tortoise-shell skin in a matter of a month or two. Her high, narrow waist turned into a slack pot belly, and her well-muscled thighs looked sunken. Not to mention her excessive thirst, frequent potty accidents (while she was asleep) and raging appetite.

In hindsight, I probably should have pushed harder on the oncologist or spoken to the internist sooner. However, I know better now, and this knowledge will definitely color any future Pred usage in my household.

Rio was on a similar regimen (minus the Palladia) to what Ajax is on two years ago when the previous MCT appeared. This time she alternated between Vinblastine and CCNU and initially, Pred.

I'm not saying that Pred isn't a valuable drug, but like Jerry said, it can also have very harmful side effects, and yet, the vets seem to hand it out like candy. In fact, when Rio's lung inflammation popped up, even with the Cushings, the first thing her vet said was that she was tempted to put her on a low dose of Pred. I love my vet, and I know that she loves Rio and would only do the best for her, but this is a case where she can't just do what she would normally do.

In my opinion, the use of Prednisone is very similar to the overuse of antibiotics (which has led to resistant bacterias). Doctors are busy folks, with many patients to see, and they tend to go with whatever has worked for them on their other cases. Additionally, patients tend to expect to get a pill (or drops or cream) to fix whatever ails them. It's our responsibility to question their doctors and get the whole picture rather than just taking the drugs that are prescribed. We have to weigh the positive effects of the drugs with their potential negative side effects.

I don't know where to post this, so will do it here – Admin, thanks for changing our avatar!  This pic is better for a Tripawds site, we think.