Prescribing Potassium Chloride via PEG Tube
Use liquid potassium chloride formulations administered through the PEG tube with proper flushing technique, dosing based on the degree of hypokalemia and renal function, typically starting with 20-40 mEq doses for mild to moderate deficits.
Formulation Selection
- Liquid (immediate-release) potassium chloride is the optimal formulation for PEG tube administration because it demonstrates rapid absorption, avoids tube occlusion risk, and allows accurate dosing 1.
- Sustained-release or extended-release formulations should be avoided through PEG tubes as they are designed for delayed absorption and may not function properly when crushed or dissolved 2.
- If only capsules are available, open the capsule and dissolve contents in 15-30 mL of water before administration, though liquid formulations remain preferred 3.
Administration Technique
- Flush the PEG tube with 30 mL of water before administering potassium chloride to ensure tube patency 3, 4.
- Administer potassium chloride separately from other medications, with 30 mL water flushes between each drug to prevent interactions and precipitation 3, 4.
- Flush the PEG tube with 30 mL of water after potassium administration to guarantee complete delivery and maintain tube patency 3, 4.
- Use ENFit-standard syringes and connectors to avoid misconnections 3, 4.
Dosing Strategy
- For mild hypokalemia (3.0-3.4 mEq/L), start with 20-40 mEq of potassium chloride per dose 1.
- For moderate hypokalemia (2.5-2.9 mEq/L), consider 40-60 mEq per dose, divided if necessary 1.
- Oral/enteral potassium supplementation is preferred over intravenous when the patient has a functioning gastrointestinal tract 1.
- Monitor serum potassium levels 2-4 hours after administration to assess response and avoid overcorrection 5.
Critical Pitfalls to Avoid
- Do not mix potassium chloride with enteral formula or other medications before administration due to risk of interactions and precipitation 3, 4.
- Never shake ENFit syringes to remove residue, as this alters the delivered dose and exposes personnel to medication 3, 4.
- Ensure the PEG tube has adequate lumen size (minimum 15 Charrière) to prevent clogging 3, 4.
- Avoid excessive potassium supplementation in patients with renal impairment or those on potassium-sparing medications (ACE inhibitors, ARBs, potassium-sparing diuretics) as this can cause life-threatening hyperkalemia 6.
Special Considerations for PEG Tube Patients
- Investigate non-dietary causes of persistent hypokalemia including metabolic acidosis, inadequate dialysis, medications, constipation, or tissue destruction 6.
- In patients with chronic kidney disease on frequent dialysis (5 sessions/week), potassium restriction may not be needed and supplementation may be required to maintain normokalemia 6.
- For patients requiring high-dose potassium supplementation chronically, consider adding potassium to enteral formula after consultation with pharmacy, though this may reduce potassium content by 12-78% if potassium binders are used 6.
- Consult a pharmacist before administering any medication through a PEG tube to confirm route suitability and verify no absorption-site constraints exist 3.
Monitoring Parameters
- Check serum potassium, renal function, and acid-base status before initiating supplementation 6, 7.
- Recheck potassium levels 2-4 hours after oral/enteral supplementation to assess response 5.
- Monitor for signs of hyperkalemia (peaked T waves, widened QRS) especially in patients receiving aggressive repletion 8, 5.
- Assess for tube patency and proper function during each administration 9, 4.