potassium salts

potassium bicarbonate
K+ Care ET

potassium chloride
Apo-K ◆, Cena-K, Gen-K, K⁺8, K-10 ◆, Kaochlor, Kaon-Cl, Kay Ciel, K+ Care, K-Dur, K-Lor, Klor-Con, Klorvess, Klotrix, K-Lyte/Cl, K-Tab, Micro-K Extencaps, Micro-K 10 Extencaps, Micro-K LS, Potasalan, Rum-K, Slow-K

potassium gluconate
Kaon, Kaylixir, K-G Elixir

Available forms
Available by prescription only
potassium bicarbonate
Tablets (effervescent): 25 mEq
potassium chloride
Capsules (controlled-release): 8 mEq, 10 mEq
Injection for I.V. infusion: 0.1mEq/ml, 0.2 mEq/ml, 0.3 mEq/ml, 0.4 mEq/ml
Injection concentrate: 1.5 mEq/ml, 2 mEq/ml
Oral liquid: 20 mEq/15 ml, 30 mEq/15 ml, 40 mEq/ 15 ml
Powder for oral administration: 15 mEq/packet, 20 mEq/packet, 25 mEq/packet
Tablets (controlled-release): 6.7 mEq, 8 mEq, 10 mEq, 20 mEq
Tablets (extended-release): 8 mEq,10 mEq
potassium gluconate
Liquid: 20 mEq/15 ml Available without a prescription
potassium gluconate
Tablets: 500 mg, 595 mg (83.45 mg and 99 mg potassium, respectively)

Indications and dosages
 Prevention of hypokalemia. Adults and children: Initially, 20 mEq of potassium supplement P.O. daily, in divided doses. Adjust dosage, p.r.n., based on serum potassium levels.
 Hypokalemia. Adults and children: 40- to 100-mEq P.O. divided into two to four doses daily. Use I.V. potassium chloride when oral replacement isn’t feasible. Maximum dose of diluted I.V. potassium chloride is 20 mEq/hour at 40 mEq/L. Further dose based on serum potassium levels. Don’t exceed 150 mEq P.O. daily in adults and 3 mEq/kg daily P.O. in children. Further doses are based on serum potassium levels and blood pH. I.V. potassium replacement should be carried out only with ECG monitoring and frequent serum potassium level determinations.
 Severe hypokalemia. Adults and children: Potassium chloride should be diluted in a suitable I.V. solution of less than 80 mEq/L and administered at no more than 40 mEq/hour. Further dose based on serum potassium levels. Don’t exceed 150 mEq I.V. daily in adults, and 3 mEq/kg I.V. daily or 40 mEq/m² daily for children. I.V. potassium replacement should be carried out only with ECG monitoring and frequent serum potassium determinations.
 Acute MI ◇. Adults: High dose-80 mEq/L at 1.5 ml/kg/hour for 24 hours with an I.V. infusion of 25% dextrose and 50 units/L regular insulin. Low dose-40 mEq/L at 1 ml/kg/hour for 24 hours, with an I.V. infusion of 10% dextrose and 20 units/L regular insulin.

Pharmacodynamics
Potassium replacement action: Potassium, the main cation in body tissue, is needed for physiologic processes such as maintaining intracellular tonicity, maintaining a balance with sodium across cell membranes, transmitting nerve impulses, maintaining cellular metabolism, contracting cardiac and skeletal muscle, maintaining acid-base balance, and maintaining normal renal function.

Pharmacokinetics
Absorption: Well absorbed from GI tract.
Distribution: Normal serum levels of potassium range from 3.8 to 5 mEq/L. Plasma potassium levels up to 7.7 mEq/L may be normal in neonates. Up to 60 mEq/L of potassium may be found in gastric secretions and diarrhea fluid.
Metabolism: None significant.
Excretion: Excreted largely by kidneys. Small amounts may be excreted via skin and intestinal tract, but intestinal potassium usually is reabsorbed. A healthy patient on a potassium-free diet will excrete 40 to 50 mEq of potassium daily.

Contraindications and precautions
Contraindicated in patients with severe renal impairment with oliguria, anuria, or azotemia; in those with untreated Addison’s disease; and in those with acute dehydration, heat cramps, hyperkalemia, hyperkalemic form of familial periodic paralysis, or conditions caused by extensive tissue breakdown.
  Use cautiously in patients with cardiac or renal disease.

Interactions
Drug-drug. ACE inhibitors, potassium-sparing diuretics: Causes severe hyperkalemia. Use cautiously.
Anticholinergics that slow GI motility: Increases risk of GI irritation and ulceration. Use together cautiously.
Digoxin: May cause arrhythmias. Potassium isn’t recommended in digitalized patients with severe or complete heart block.
Products that contain potassium: Causes hyperkalemia within 1 to 2 days. Monitor patient closely.
Drug-food. Salt substitutes that contain potassium salts: Causes severe hyperkalemia. Avoid use together.

Adverse reactions
CNS: paresthesia of the limbs, listlessness, mental confusion, weakness or heaviness of legs, flaccid paralysis, fever.
CV: hypotension, arrhythmias, cardiac arrest, heart block, ECG changes.
GI: nausea, vomiting, abdominal pain, diarrhea, GI bleeding, ulcer, perforation, obstruction (with oral forms).
Metabolic: hyperkalemia.
Respiratory: respiratory paralysis.
Skin: pain and redness at infusion site.

Effects on lab test results
• May increase potassium levels.

Overdose and treatment
Toxicity causes increased serum potassium level and characteristic ECG changes, including tall peaked T waves, depression of ST segment, disappearance of P wave, prolonged QT interval, and widening and slurring of the QRS complex. Late signs of toxicity include weakness, paralysis of voluntary muscles, respiratory distress, and dysphagia. These may precede severe or fatal cardiac toxicity. Hyperkalemia produces symptoms paradoxically similar to those of hypokalemia.
 For patients with a potassium level greater than 6.5 mEq/L, supportive therapy may include the following interventions (with continuous ECG monitoring): Infuse 40 to 160 mEq sodium bicarbonate I.V. over a 5-minute interval; repeat in 10 to 15 minutes if ECG abnormalities persist. Infuse 300 to 500 ml of dextrose 10% to 25% over 1 hour. Insulin (5 to 10 units per 20 g of dextrose) should be added to the infusion or, ideally, administered as a separate injection.
 Patients with absent P waves or broad QRS complex who aren’t receiving cardiotonic glycosides should immediately be given 0.5 g to 1 g of calcium gluconate or another calcium salt I.V. over a 2-minute period (with continuous ECG monitoring) to antagonize cardiotoxic effect of potassium. May be repeated in 1 to 2 minutes if ECG abnormalities persist.
 To remove potassium from body, use sodium polystyrene sulfonate resin, hemodialysis, or peritoneal dialysis. Administer potassium-free I.V. fluids when hyperkalemia is linked to water loss.

Special considerations
• In patients receiving cardiac glycosides, removing potassium too rapidly may result in digitalis toxicity.
• Don’t give potassium during immediate postoperative period until urine flow is established.
• Monitor serum potassium, BUN, and serum creatinine levels before starting therapy.
• Monitor ECG, pH, serum potassium levels, and other electrolytes during therapy.
• Give parenteral potassium by slow infusion only, never by I.V. push or I.M. Dilute I.V. potassium preparations with large volume of parenteral solutions.
• Give oral potassium supplements with extreme caution because its many forms deliver varying amounts of potassium. Patient may tolerate one product better than another.
• Oral form should be taken with meals and sipped slowly over a 5- to 10-minute period to decrease irritation.
• Potassium gluconate doesn’t correct hypokalemic hypochloremic alkalosis.
• Tablets in wax matrix sometimes lodge in esophagus and cause ulceration in cardiac patients who have esophageal compression caused by enlarged left atrium. In such patients and in those with esophageal or GI stasis or obstruction, use liquid form.
• Drug is often used orally with diuretics that cause potassium excretion. Potassium chloride is most useful because diuretics waste chloride ions. Hypokalemic alkalosis is treated best with potassium chloride.
• Don’t crush controlled or extended-released potassium products.
Breast-feeding patients
• Potassium supplements appear in breast milk. Safety in breast-feeding women hasn’t been established; use potassium only when benefits to mother outweigh risks to infant.
Pediatric patients
• Use cautiously in children.

Patient education
• Suggest diluting liquid potassium product in at least 4 to 8 oz (120 to 240 ml) of water; to take it after meals; and to sip liquid potassium slowly to minimize GI irritation.
• Tell patient to dissolve powder, soluble tablets, or granules completely in at least 4 oz (120 ml) of water or juice, and to allow fizzing to finish before drinking.
• Instruct patient not to crush or chew sustained-release capsules; contents of capsule can be opened and sprinkled onto applesauce or other soft food.
• Tell patient to stop taking drug and report immediately if the following reactions occur: confusion; irregular heartbeat; numbness of feet, fingers, or lips; shortness of breath; anxiety; excessive tiredness or weakness of legs; unexplained diarrhea; nausea and vomiting; stomach pain; or bloody or black stools. Such reactions are rare.
• Tell patient that expelling a whole sustained-release tablet in stool is normal. The body eliminates the shell after absorbing the potassium.
• Warn patient to avoid salt substitutes except when prescribed.
• Take with meals to avoid GI irritation.

Reactions may be common, uncommon, life-threatening, or COMMON AND LIFE THREATENING.
◆ Canada only
◇ Unlabeled clinical use