Dialysis: controlling PTH, calcium and phosphate with Sensipar®

Dialysis: controlling PTH, calcium and phosphate with Sensipar®
dialyblog | September 16, 2011 at 5:32 pm | Categories: Healthy dialysis | BLOG URL: http://wp.me/puMEh-bZ
I’ve had an annoying excess phosphate/calcium problem for about a year. I knew it was a problem because I developed a maddening itch, on my arms, chest, legs and back. It drove me crazy. And each time I started to scratch it just got worse. I found it hard to stop, and constant scratching in polite society is a real conversation killer. Eventually I found ways to minimise it, but now I have just about stopped it at the cause.
Kidneys specialise in more than urine, they also manage the calcium and phosphate mix through the parathyroid glands in your neck (see this post). Once they leave the building, the calcium and phosphate mix in the bloodstream can go haywire, causing the parathyroid glands to release too much parathyroid hormone (PTH). This creates a range of problems from itchiness to bone disease, heart disease and abnormal calcium deposits in blood vessels and other parts of the body (including the brain!).
One way to control this is to take phosphate binders (like Caltrate) with each meal. These binders attach themselves to the phosphate in the meal and then head for the bowel, rather than allowing the phosphate to bind with the calcium in the bloodstream.
In dealing with this problem, my nephrologist first upped the number of Caltrate (calcium) phosphate binders I took, then offered a different type, Alutabs (aluminium hydroxide), made from aluminium. There has been lots of studies that indicate aluminium is one of the causes of Alzheimer’s Disease, so I politely declined. Some side effects are better than others, but Alzheimer’s ain’t one of them.
Then we tried Renagel (sevelamer hydrochloride if you prefer), which also didn’t suit. Side effects vary with each person, and mine were stomach ache and diarrhea, so no. Finally we settled on Fosrenol® (lanthanum carbonate hydrate) a horse pill-sized chewable tablet I take with meals. This worked initially, but gradually my PTH jumped again.
This had happened to me before. Then, the only way to stop the glands was to surgically remove them. I had 90 percent parathyroidectomy in 2001, but over the next ten years they grew back even stronger (if only kidneys could learn that trick).
Now they can be stopped with a drug. It’s called Cinacalcet, or Sensipar®. It lowers PTH by telling my parathyroid glands to stop releasing too much PTH into my blood. It also lowers calcium and phosphate levels. I think of it as chemical surgery. Once you start, the tests and management is the same as surgery. I started on 30mg per day and daily blood tests to track my PTH, phosphate and calcium levels.
Ideal levels are:
PTH: between 15- 21 pmol/L
Corrected calcium: 2.2 – 2.4 mmol/l
Phosphate: 1.1 – 1.8 mmol/l.
It took about a week for my PTH level to fall into the ideal range. Once there I cut back to 30 mg every second day and twice-weekly blood tests. My calcium and phosphate gradually fell over two weeks. In fact the calcium fell below the ideal range, so I now take two Caltrate between meals, to boost my blood level calcium.
Sensipar’s most common side effects are dizziness, skin tingling, nausea and vomiting, with the usual undesirables less likely. Fortunately, so far, touch wood, mine are minimal (and I would like them to stay that way). Once all is under control and stable, I will go to weekly blood tests.
I have been on Sensipar now for about a month. Early days, but worth documenting. I’m looking forward to two main benefits: reduced itchiness (which is happening, I don’t use the creams anymore) and my bones recovering the calcium that has been leached from them over the last year. I won’t be able to feel that when it happens, but, I have a bone density test coming up next year, and I am expecting good news.
I’ll let you know how things proceed.