Clinical Twisters: Managing ESRD following MI

A 50-year-old man, C.C., has been hospitalized for acute myocardial infarction (MI) and a stent was placed. C.C. also has end-stage renal disease (ESRD) and is on three-times-weekly hemodialysis. Post-MI, his physician has prescribed metoprolol 50 mg b.i.d., ramipril (Altace, King Pharmaceuticals) 10 mg q.d., atorvastatin (Lipitor, Pfizer) 10 mg q.d., nitroglycerin 0.4 mg sublingual, warfarin 5 mg q.d., and clopidogrel (Plavix, Sanofi-Aventis) 75 mg q.d. C.C.'s predialysis lab values today are parathyroid hormone=405 pg/dl, corrected Ca=10.3 mg, P=5.7 mg, Ca x P 58.71 mg²/dl². Dialysate calcium concentration is 2.4 mEq/L. C.C.'s nephrologist is evaluating whether to change his preexisting regimen of calcium acetate and calcitriol. What do you suggest?

Based on C.C.'s lab work, a small increase in calcitriol dose may be indicated, particularly if the PTH (parathyroid hormone) is rising from his most recent level. The phosphate binder could also be switched to a non-calcium-based product such as sevelamer (Renagel, Genzyme) or lanthanum carbonate, which will help prevent the calcium level from rising further. Cinacalcet (Sensipar, Amgen) might be an option for C.C. to help control PTH. However, I'd make sure that vitamin D and phosphate binder therapy are optimized before adding cinacalcet due to its high cost.

We typically do not use dialysate calcium baths of much less than 2.4mEq/L. So I would not change the dialysate calcium concentration. If calcium control continues to be a problem, calcitriol could be changed to another vitamin D analog such as paricalcitol (Zemplar, Abbott) or doxercalciferol (Hectorol, Bone Care International). These agents are very effective at lowering PTH levels without the propensity to cause the hypercalcemia and hyperphosphatemia associated with calcitriol.

Mark Recker, Pharm.D. Pharmacy ManagerLima Memorial HospitalLima, Ohio

C.C. requires better calcium and phosphorus control. Each of his laboratory values exceeds K/DOQI guidelines, and his recent MI indicates high cardiovascular risk. The consequences of calcium and phosphorus imbalance are well known and include both bone disease and increased cardiovascular mortality.

I'd replace calcium acetate with sevelamer and calcitriol with paricalcitol. Sevelamer is a nonabsorbed polymer that binds phosphate without increasing calcium levels and also lowers serum cholesterol. Lanthanum carbonate would be an alternative, but there is less experience with it, and its cholesterol- lowering properties have not been reported. I would continue vitamin D therapy to suppress PTH, substituting paricalcitol for calcitriol, as it is less likely to cause hypercalcemia and hyperphosphatemia. I'd leave dialysate calcium the same, assuming the above measures will adequately lower calcium.

C.C. should be reminded of the importance of limiting phosphorus intake, taking sevelamer with meals, and not missing doses. Recommended follow-up includes calcium and phosphorus level checks in two and four weeks and PTH in one month. Sevelamer and paricalcitol doses should be titrated to the following targets: corrected calcium 8.4-9.5 mg/dl, phosphorus 3.5-5.5 mg/dl, Ca x P < 55 mg²/dl², and iPTH 150-300 pg/ml.

Teddie Gould, M.S., R.Ph., BCPS Associate Professor of Pharmacy PracticeIdaho State UniversityPocatello, Idaho