K+

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Introduction

The total body K+ content in an adult is about 2500-3000 meq. About 98% of K+ is intracellular. Concentration of K+ is about 160 meq/L intracellularly & 3.5-5.0 meq/L extracellularly. K+ is the main intracellular cation & the K+ gradient across the cell membrane provides the force behind the negative potential & electrical excitability of cells. The Na+/K+ ATPase maintains the intracellular K+ concentration.

Mechanisms regulating extracellular K+ concentration:

Dietary K+ occurs as potassium phosphate.

Generally, green leafy vegetables, fruits, & root vegetables are good dietary sources of K+. A dietary K+ intake of 120 mEq/day or more is safe for healthy people, since excess K+ is excreted in the urine. However, patients with renal insufficiency, adrenal insufficiency, the elderly, & patients on ACE inhibitors, ARBs, NSAIDs, or potassium-sparing diuretics may need to monitor K+ intake (& serum K+).[1]

More general terms

Additional terms

Component of

References

  1. 1.0 1.1 Prescriber's Letter 15(9): 2008 Potassium Content of Foods and Salt Substitutes Detail-Document#: http://prescribersletter.com/(5bhgn1a4ni4cyp2tvybwfh55)/pl/ArticleDD.aspx?li=1&st=1&cs=&s=PRL&pt=3&fpt=25&dd=240904&pb=PRL (subscription needed) http://www.prescribersletter.com
  2. Gumz ML, Rabinowitz L, Wingo CS An Integrated View of Potassium Homeostasis. N Engl J Med 2015; 373:60-72. July 2, 2015 <PubMed> PMID: https://www.ncbi.nlm.nih.gov/pubmed/26132942 <Internet> http://www.nejm.org/doi/full/10.1056/NEJMra1313341

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