title: Extrarenal effect of cyclosporine A on potassium homeostasis in renal transplant recipients.
abstract: Cyclosporine A (CyA) is known to cause hyperkalemia by impairing renal potassium excretion. However, the observation of transient and severe hyperkalemia occurring within 3 to 5 hours of CyA ingestion in several organ transplant patients led us to postulate that it might also cause a potassium efflux from the intracellular to the extracellular fluid space. We tested this hypothesis by studying 22 nondiabetic, renal transplant patients with stable renal function (serum creatine < 2.25 mg/dL) who were treated with CyA (CyA group; n = 14) or imuran and prednisone (STD group; n = 8). Eight CyA and four STD patients also were treated with a beta-blocker (BB). While at rest, fasting plasma potassium levels were sampled hourly in all patients from 8:00 am to 1:00 pm. All medications (including CyA and BBs) were given after the 8:00 am blood sampling. Venous pH, osmolality, insulin, aldosterone, epinephrine, norepinephrine, and CyA levels also were determined at 8:00 am, 11:00 am, and 1:00 pm. Urine was collected from 11:00 pm to 8:00 am prior to the study (period I) and from 8:00 am to 1:00 pm during the study (period II) for measurement of potassium excretion (standardized to a 5-hour period). A significant increase in serial plasma potassium levels was noted in the CyA + BB group only (P = 0.0006 by repeated measures analysis of variance).(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Division of Nephrology, Toronto Hospital, Ontario, Canada.
authors.forename: Y
authors.initials: Y
authors.lastname: Pei
authors.forename: R
authors.initials: R
authors.lastname: Richardson
authors.forename: C
authors.initials: C
authors.lastname: Greenwood
authors.forename: P Y
authors.initials: PY
authors.lastname: Wong
authors.forename: A
authors.initials: A
authors.lastname: Baines
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D016572:Cyclosporine / Q000009:adverse effects* / Q000627:therapeutic use; D005260:Female; D006706:Homeostasis / Q000187:drug effects; D006801:Humans; D006947:Hyperkalemia / Q000139:chemically induced*; D016030:Kidney Transplantation / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D011188:Potassium / Q000097:blood / Q000652:urine; D013997:Time Factors
chemical_list: D016572:Cyclosporine; D011188:Potassium