The Pharmacokinetics of Potassium in Humans Is Unusual

Abstract

Potassium is critical for maintaining cellular tonicity, propagation of nerve impulses, contraction of cardiac, skeletal, and smooth muscles, and normal renal function. The focus of this review is on the pharmacokinetics of potassium, K + , after administration of liquid and solid formulations of potassium chloride, KCl, to healthy subjects. Potassium can be considered an endogenous and exogenous compound. The amounts of endogenous K + are kept constant by balancing intake and loss of exogenous K + . Food and ingestion of KCl-containing medicines are sources for exogenous K + . In the pharmacokinetic context exogenous K + from KCl-containing medicines, K + exo,dose , is of primary interest. The distinction between the different K + entities is critical for obtaining unbiased estimates of the kinetic parameters for K + exo,dose . A literature search using prespecified acceptance criteria was performed. Publications were selected that reported plasma and urine data of K + exo,dose directly or provided information allowing their determination. Additional criteria applied included that the studies used a randomized design and controlled for the important covariates. Most of the selected publications reported urinary excretion data. Only 2 publications also reported plasma concentrations. The excursions of the plasma concentrations of K + exo,dose were considered too small to be of use by most investigators. The aggregate results indicate that urinary recovery data have the potential for providing reliable estimates for bioavailability and bioequivalence of K + exo,dose with KCl-containing formulations. Absorption efficiency, peak rates, and corresponding times of K + exo,dose with liquid formulations are fairly consistent among studies. The mean absorption efficiency of K + exo,dose with solid and liquid formulations of KCl ranges between 70% and 90%. The absorption rate of liquid formulations is rapid, whereas the solid formulations show extended release characteristics. The time-averaged renal clearance of K + exo,dose is about 200 mL/min during daytime and significantly smaller around midnight. Circadian rhythm and delayed homeostatic control of potassium make the pharmacokinetics of K + exo,dose time dependent. The impact of these endogenous controls makes the pharmacokinetics of K + exo,dose unusual. Keywordspotassium, exogenous, endogenous, humans, pharmacokinetics, renal clearance Products containing potassium chloride (KCl) for intravenous infusion and oral administration are approved for marketing in the United States for the treatment and prevention of hypokalemia with or without metabolic alkalosis in adults and in the pediatric population, in digitalis intoxication, and in patients with hypokalemic familial periodic paralysis. KCl is also indicated for the prevention of hypokalemia in adult and pediatric patients who would be of particular risk if hypokalemia were to develop, eg, in digitalized patients with significant cardiac arrhythmias. The potassium component of KCl reduces hypokalemia, and t...

Diet or Additional Supplement to Increase Potassium Intake: Protocol For An Adaptive Clinical Trial

“…There are no reports of hyperkalemia reported in trials using this dose in a similar population [9,12]. Potassium at this dose and formulation has excellent (> 90%) bioavailability [19]. This dose of potassium also should be effective in increasing urinary potassium to desired levels.…”

“…They will receive oral potassium supplementation in the form of 50 to 100 mmol of potassium citrate (25 to 50 ml of the liquid elixir). This dose of potassium is well tolerated in hypertension (reported adverse events, at < 1% frequency and not different from placebo, are change in bowel habits, belching and atulence, and abdominal cramps with the current wax matrixbased and microencapsulated or coated microcrystal-containing preparations with extended release characteristics) [9,19]. There are no reports of hyperkalemia reported in trials using this dose in a similar population [9,12].…”

Diet or additional supplement to increase potassium intake: protocol for an adaptive clinical trial

“…This dose of potassium is well tolerated in hypertension (reported adverse events, at < 1% frequency and not different from placebo, are change in bowel habits, belching and flatulence, and abdominal cramps with the current wax matrix-based and microencapsulated or coated microcrystal-containing preparations with extended release characteristics) [ 9 , 20 ]. There are no reports of hyperkalemia reported in trials using this dose in a similar population [ 9 , 13 ].…”

“…There are no reports of hyperkalemia reported in trials using this dose in a similar population [ 9 , 13 ]. Potassium at this dose and formulation has excellent (> 90%) bioavailability [ 20 ]. This dose of potassium also should be effective in increasing urinary potassium to desired levels.…”

ICRP Publication 151: Occupational Intakes of Radionuclides: Part 5

“…Nickel was given as the sulphate either with drinking water or with a standard North American breakfast. The authors estimated absorbed fractions of ∼0.01 for nickel in food and ∼0.3 for nickel in drinking water. (278) Hindsen et al. (1994) measured nickel concentrations in blood and urine of 52 female patients with five different types of eczema 3 h and 24 h, respectively, after ingestion of 1 mg of nickel as the sulphate in lactose.…”