K-Dur

Action

Maintains acid-base balance, isotonicity, and electrophysiologic balance throughout body tissues; crucial to nerve impulse transmission and contraction of cardiac, skeletal, and smooth muscle. Also essential for normal renal function and carbohydrate metabolism.

Availability

Capsules (extended-release): 8 mEq, 10 mEq

Powder for oral solution: 20 mEq, 25 mEq

Parenteral injection (concentrate): 2 mEq/ml

Parenteral solution: 0.1 mEq/ml, 0.2 mEq/ml, 0.3 mEq/ml, 0.4 mEq/ml

Potassium chloride in 5% dextrose injection: 10 mEq/L, 20 mEq/L, 30 mEq/L, 40 mEq/L

Potassium chloride in 0.9% sodium chloride injection: 20 mEq/L, 40 mEq/L

Potassium chloride in dextrose and lactated Ringer's injection: various strengths

Potassium chloride in dextrose and sodium chloride injection: various strengths

Solution (oral): 6.7 mEq, 10 mEq, 13.3 mEq, 15 mEq, 20 mEq, 30 mEq, 40 mEq

Tablets: 500 mg, 595 mg

Tablets (effervescent): 25 mEq, 50 mEq

Tablets (extended-release): 8 mEq, 10 mEq, 20 mEq

Tablets (extended-release crystals): 10 mEq, 20 mEq

Tablets (extended-release, film coated): 8 mEq, 10 mEq

Tablets (film-coated): 2.5 mEq, 10 mEq

Indications and dosages

➣ To prevent potassium depletion

Adults: Dosage highly individualized. Usual single dosage is 20 mEq/day P.O. in divided doses.

➣ Potassium depletion; diabetic acidosis; metabolic alkalosis; arrhythmias; periodic paralysis attacks; hyperadren-ocorticism; primary aldosteronism; healing phase of scalds or burns; over-medication with adrenocorticoids, testosterone, or corticotropin

Adults: Dosage highly individualized. 40 to 100 mEq/day P.O. in divided doses, not to exceed 20 mEq in a single dose. For serum potassium level above 2.5 mEq/L, 40 mEq/L as additive to I.V. infusion at a maximum rate of 10 mEq/hour; maximum daily dosage is 200 mEq. For serum potassium level less than 2 mEq/L, 80 mEq/L as additive to I.V. infusion at a maximum rate of 40 mEq/hour (with cardiac monitoring); maximum daily dosage is 400 mEq.

Children: Dosage highly individualized; give up to 3 mEq/kg or 40 mEq/m²/day as additive to I.V. infusion.

Contraindications

• Hypersensitivity to tartrazine or alcohol (with some products)

• Acute dehydration

• Heat cramps

• Hyperkalemia

• Hyperkalemic familial periodic paralysis

• Severe renal impairment

• Severe hemolytic reactions

• Severe tissue trauma

• Untreated Addison's disease

• Esophageal compression caused by enlarged left atrium (with wax matrix forms)

• Concurrent use of potassium-sparing diuretics, angiotensin-enzyme converting (ACE) inhibitors, or salt substitutes containing potassium

Precautions

Use cautiously in:

• cardiac disease, renal impairment, diabetes mellitus, hypomagnesemia

• pregnant or breastfeeding patients

• children (safety and efficacy not established).

Administration

☞ Know that I.V. potassium chloride is a high-alert drug.

☞ Give I.V. form as additive by infusion only. Never give undiluted or by I.V. push or I.M. route. Use peripheral line and infuse at a maximum rate of 40 mEq/hour (with cardiac monitoring).

☞ Dilute in compatible I.V. solution per manufacturer's instructions. Administer slowly to reduce risk of fatal hyperkalemia.

☞ To ensure that potassium is well mixed in compatible solution, don't add potassium to I.V. bottle in hanging position.

☞ Be aware that maximum infusion rate without cardiac monitoring is 20 mEq/hour. Rates above 20 mEq/hour require cardiac monitoring.

• Make sure patient is well-hydrated and urinating before starting therapy.

• If patient complains of burning with I.V. administration, decrease flow rate.

• Give P.O. form with meals and a full glass of water or juice, to minimize GI upset.

• Ensure that patient swallows wax-matrix tablets completely, to avoid serious esophageal problems.

• Don't give wax matrix tablets to patients who have swallowing problems or possible esophageal compression.

• Be aware that potassium preparations aren't interchangeable.

• Know that dosages are expressed in mEq of potassium and that potassium chloride contains 13.4 mEq potassium/g.

Adverse reactions

CNS: confusion, unusual fatigue, restlessness, asthenia, flaccid paralysis, paresthesia, absent reflexes

CV: ECG changes, hypotension, arrhythmias, heart block, cardiac arrest

GI: nausea, vomiting, diarrhea, abdominal discomfort, flatulence

Metabolic: hyperkalemia

Musculoskeletal: weakness and heaviness of legs

Respiratory: respiratory paralysis Other: irritation at I.V. site

Interactions

Drug-drug. ACE inhibitors, potassium-sparing diuretics, other potassium-containing preparations: increased risk of hyperkalemia

Drug-diagnostic tests. Potassium: increased level

Drug-food. Salt substitutes containing potassium: increased risk of hyperkalemia

Drug-herbs. Dandelion: increased risk of hyperkalemia

Licorice: decreased response to potassium

Patient monitoring

• Monitor renal function, fluid intake and output, and potassium, creatinine, and blood urea nitrogen levels.

• Assess vital signs and ECG. Stay alert for arrhythmias.

• Monitor neurologic status. Watch for neurologic complications.

• Monitor I.V. site for irritation.

☞ Know that potassium is contra-indicated in patients with severe renal impairment and must be used with extreme caution (if at all) in patients with any degree of renal impairment, because of risk of life-threatening hyperkalemia.

Patient teaching

• Instruct patient to mix and dissolve powder completely in 3 to 8 oz of water or juice.

• Tell patient to swallow extended-release capsules whole without crushing or chewing them.

• Instruct patient to take oral form with or just after a meal, with a glass of water or fruit juice.

• Tell patient to sip diluted liquid form over 5 to 10 minutes.

• Advise patient to report nausea, vomiting, confusion, numbness and tingling, unusual fatigue or weakness, or a heavy feeling in legs.

• Tell patient to minimize GI upset by eating frequent, small servings of food and drinking plenty of fluids.

• Inform patient that although wax matrix form may appear in stool, drug has already been absorbed.

• Advise patient not to use salt substitutes.

• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs, tests, foods, and herbs mentioned above.