Hyponatraemia and hyperkalaemia are more frequent in renal transplant recipients treated with tacrolimus than with cyclosporin. Further evidence for differences between cyclosporin and tacrolimus nephrotoxicities.
BACKGROUND
This study was designed to examine the hypothesis that the nephrotoxicities caused by cyclosporin and tacrolimus might differ in respect of sodium and potassium handling.


METHODS
125 patients were studied retrospectively for the first 90 days after renal transplantation. Eighty were treated initially with cyclosporin and 45 with tacrolimus.


RESULTS
A serum sodium level of <135 mmol/l was present for 542/5171 (10.5%) days under tacrolimus treatment compared with 377/5486 (6.9%) days under cyclosporin treatment (P < 0.0001). Severe hyponatraemia, below 120 mmol/l, was also more prevalent under tacrolimus than cyclosporin treatment, P < 0.025. Nine patients, all receiving tacrolimus, were treated with fludrocortisone for fluid depletion and/or hyponatraemia. Serum potassium levels were higher in tacrolimus-treated patients (P < 0.0001), and subjects with hyponatraemia were more likely to experience hyperkalaemia (P < 0.0001).


CONCLUSIONS
Hyponatraemia and hyperkalaemia were more frequent in tacrolimus-treated subjects. Taken together with previous work showing that hyperuricaemia is more frequent with cyclosporin treatment, and hypomagnesaemia with tacrolimus treatment, these findings are consistent with qualitative differences between the nephrotoxicities of cyclosporin and tacrolimus.
Higgins
Robert
R
Renal Transplant Unit, University Hospitals Coventry and Warwickshire, Walsgrave Hospital, Coventry, UK. robert.higgins@uhcw.nhs.uk
Ramaiyan
Karam
K
Dasgupta
Tanaji
T
Kanji
Hemali
H
Fletcher
Simon
S
Lam
For
F
Kashi
Habib
H
D000328:Adult; D016572:Cyclosporine / Q000008:administration & dosage / Q000009:adverse effects*; D005260:Female; D005500:Follow-Up Studies; D006084:Graft Rejection / Q000517:prevention & control; D006085:Graft Survival; D006801:Humans; D006947:Hyperkalemia / Q000139:chemically induced / Q000453:epidemiology*; D007010:Hyponatremia / Q000139:chemically induced / Q000453:epidemiology*; D007166:Immunosuppressive Agents / Q000008:administration & dosage / Q000009:adverse effects; D007676:Kidney Failure, Chronic / Q000601:surgery; D016030:Kidney Transplantation / Q000276:immunology* / Q000379:methods; D008297:Male; D008875:Middle Aged; D011182:Postoperative Care; D015995:Prevalence; D011336:Probability; D012189:Retrospective Studies; D018570:Risk Assessment; D012720:Severity of Illness Index; D016559:Tacrolimus / Q000008:administration & dosage / Q000009:adverse effects*; D014181:Transplantation Immunology / Q000187:drug effects / Q000502:physiology; D016896:Treatment Outcome
D007166:Immunosuppressive Agents; D016572:Cyclosporine; D016559:Tacrolimus