Assessment of Ondansetron-Associated Hypokalemia in Pediatric Oncology Patients

Table 2

Comparative values of TTKG, Na and K balance before and after ondansetron show no effect on renal K wasting.

	𝑛	Before ondansetron	After ondansetron	𝑃
PK (mmol/L)	10	3.9 ± 0.3	3.9 ± 0.2	0.774
UK (mmol/L)	10	50.7 ± 22.7	24.7 ± 22.8	0.019
POsm (mmol/kg)	10	287.2 ± 4.2	283.8 ± 18.0	0.573
UOsm (mmol/kg)	10	761.4 ± 183.3	356.7 ± 123.4	0.001
PAld (pmol/L)	10	323.4 ± 484.8	153.9 ± 268.5	0.353
TTKG	5*	5.1 ± 1.9	4.7 ± 2.8	0.463
eGFR (ml/min/1.73 m^2)	10	148.9 ± 17.9	166.8 ± 46.8	0.207
PNa (mmol/L)	10	138.6 ± 1.8	133.9 ± 18.0	0.426
FENa (%)	10	0.8 ± 0.6	3.1 ± 2.54	0.025
Balance studies
Na intake (mmol)	10	2840.0 ± 2034.1	8032.8 ± 7257.5	0.080
Na output (mmol)	10	50.7 ± 22.7	113.8 ± 41.6	0.002
K intake (mmol)	10	1459.7 ± 1306.1	2274.0 ± 1693.0	0.347
K output (mmol)	10	50.7 ± 22.7	24.8 ± 22.8	0.019
Net Na balance (mmol/kg/hr observation)	10	0.15 ± 0.39	0.06 ± 0.11	0.520
Net K balance (mmol/kg/hr observation)	10	0.11 ± 0.07	0.39 ± 0.82	0.305

Values are presented as mean ± standard deviation.
Student’s 𝑡-test, paired, two-tailed, significance 𝑃 < 0.05.
Net balance = (intake − output)/weight (kg)/time (hr) of observation period.
PK: plasma potassium, mmol/L; UK: urine K, mmol/L; Posm: plasma osmolality, mmol/kg; Pald: plasma aldosterone, pmol/L (lower limit of detection 69 pmol/L); TTKG: transtubular potassium gradient; eGFR: estimated glomerular filtration rate (Schwartz [15]); Pna: plasma sodium, mmol/L; FENa: fractional excretion of sodium (%).
*5 subjects were not included in this analysis as they developed hypotonic urine relative to blood, invalidating the TTKG assumptions.