2.1 Administration and Monitoring

If serum potassium concentration is less than 2.5 mEq/L, use intravenous potassium instead of oral supplementation.

2.2 Dosing

Dosage must be adjusted to the individual needs of each patient. Dosages greater than 40 mEq per day should be divided such that no more than 40 mEq is given in a single dose.

5.1 Gastrointestinal Adverse Reactions

Solid oral dosage forms of potassium chloride can produce ulcerative and/or stenotic lesions of the gastrointestinal tract, particularly if the drug maintains contact with the gastrointestinal mucosa for prolonged periods. Consider the use of liquid potassium in patients with dysphagia, swallowing disorders, or severe gastrointestinal motility disorders.

If severe vomiting, abdominal pain, distention, or gastrointestinal bleeding occurs, discontinue potassium chloride extended-release tablets and consider possibility of ulceration, obstruction or perforation.

Potassium chloride extended-release tablets should not be taken on an empty stomach because of its potential for gastric irritation [see Dosage and Administration (2.1)] .

7.1 Triamterene or amiloride

Use with triamterene or amiloride can produce severe hyperkalemia. Concomitant use is contraindicated [see Contraindications (4)] .

7.2 Renin-angiotensin-aldosterone Inhibitors

Drugs that inhibit the renin-angiotensin-aldosterone system (RAAS) including angiotensin converting enzyme (ACE) inhibitors, angiotensin receptor blockers (ARBs), spironolactone, eplerenone, or aliskiren produce potassium retention by inhibiting aldosterone production. Closely monitor potassium in patients on concomitant RAAS inhibitors.

7.3 Nonsteroidal Anti-inflammatory Drugs (NSAIDs)

NSAIDs may produce potassium retention by reducing renal synthesis of prostaglandin E and impairing the renin-angiotensin system. Closely monitor potassium in patients on concomitant NSAIDs.

8.1 Pregnancy

8.2 Lactation

8.4 Pediatric Use

Safety and effectiveness in the pediatric population have not been established.

8.5 Geriatric Use

Clinical studies of potassium chloride extended-release did not include sufficient numbers of subjects aged 65 and over to determine whether they respond differently from younger subjects. Other reported clinical experience has not identified differences in responses between the elderly and younger patients. In general, dose selection for an elderly patient should be cautious, usually starting at the low end of the dosing range, reflecting the greater frequency of decreased hepatic, renal or cardiac function, and of concomitant disease or other drug therapy.

This drug is known to be substantially excreted by the kidney, and the risk of toxic reactions to this drug may be greater in patients with impaired renal function. Because elderly patients are more likely to have decreased renal function, care should be taken in dose selection, and it may be useful to monitor renal function.

8.6 Cirrhotics

Based on published literature, the baseline corrected serum concentrations of potassium measured over 3 hours after administration in cirrhotic subjects who received an oral potassium load rose to approximately twice that of normal subjects who received the same load. Patients with cirrhosis should usually be started at the low end of the dosing range, and the serum potassium level should be monitored frequently [see Clinical Pharmacology (12.3)] .

8.7 Renal Impairment

Patients with renal impairment have reduced urinary excretion of potassium and are at substantially increased risk of hyperkalemia. Patients with impaired renal function, particularly if the patient is on RAAS inhibitors or NSAIDs, should usually be started at the low end of the dosing range because of the potential for development of hyperkalemia [see Drug Interactions (7.2, 7.3)] . The serum potassium level should be monitored frequently. Renal function should be assessed periodically.

10.1 Symptoms

The administration of oral potassium salts to persons with normal excretory mechanisms for potassium rarely causes serious hyperkalemia. However, if excretory mechanisms are impaired, potentially fatal hyperkalemia can result [see Contraindications and Warnings] .

It is important to recognize that hyperkalemia is usually asymptomatic and may be manifested only by an increased serum potassium concentration (6.5 mEq/L to 8.0 mEq/L) and characteristic electrocardiographic changes (peaking of T-waves, loss of P-wave, depression of S-T segment and prolongation of the QT interval). Late manifestations include muscle paralysis and cardiovascular collapse from cardiac arrest (9 to 12 mEq/L).

10.2 Treatment

Treatment measures for hyperkalemia include the following:

• Elimination of foods and medications containing potassium and of any agents with potassium-sparing properties.
• Intravenous administration of 300 mL/hr to 500 mL/hr of 10% dextrose solution containing 10 to 20 units of crystalline insulin per 1,000 mL.
• Correction of acidosis, if present, with intravenous sodium bicarbonate.
• Use of exchange resins, hemodialysis or peritoneal dialysis.

In treating hyperkalemia, it should be recalled that in patients who have been stabilized on digitalis, too rapid a lowering of the serum potassium concentration can produce digitalis toxicity.

The extended-release feature means that absorption and toxic effects may be delayed for hours. Consider standard measures to remove any unabsorbed drug.

12.1 Mechanism of Action

The potassium ion is the principal intracellular cation of most body tissues. Potassium ions participate in a number of essential physiological processes including the maintenance of intracellular tonicity, the transmission of nerve impulses, the contraction of cardiac, skeletal and smooth muscle and the maintenance of normal renal function.

The intracellular concentration of potassium is approximately 150 mEq to 160 mEq per liter. The normal adult plasma concentration is 3.5 mEq to 5 mEq per liter. An active ion transport system maintains this gradient across the plasma membrane.

Potassium is a normal dietary constituent and under steady state conditions the amount of potassium absorbed from the gastrointestinal tract is equal to the amount excreted in the urine. The usual dietary intake of potassium is 50 to 100 mEq per day.

12.3 Pharmacokinetics

The potassium chloride in potassium chloride extended-release is completely absorbed before it leaves the small intestine. The wax matrix is not absorbed and is excreted in the feces; in some instances the empty matrices may be noticeable in the stool. When the bioavailability of the potassium ion from the potassium chloride extended-release is compared to that of a true solution the extent of absorption is similar.

The extended-release properties of potassium chloride extended-release are demonstrated by the finding that a significant increase in time is required for renal excretion of the first 50% of the Potassium chloride extended-release dose as compared to the solution.

Increased urinary potassium excretion is first observed 1 hour after administration of potassium chloride extended-release, reaches a peak at approximately 4 hours, and extends up to 8 hours.

Mean daily steady-state plasma levels of potassium following daily administration of potassium chloride extended-release tablets cannot be distinguished from those following administration of potassium chloride solution or from control plasma levels of potassium ion.

13.1 Carcinogenesis, Mutagenesis and Impairment of Fertility

Carcinogenicity, mutagenicity and fertility studies in animals have not been performed. Potassium is a normal dietary constituent.

Store at 20° to 25°C (68° to 77°F); excursions permitted to 15° to 30°C (59° to 86°F) [See USP Controlled Room Temperature].

Dispense in a tight container with a child-resistant closure.

Keep tightly closed.