Micro-K® Extencaps® capsules and Micro-K® 10 Extencaps® capsules are oral dosage forms of microencapsulated potassium chloride containing 600 and 750 mg, respectively, of potassium chloride USP equivalent to 8 and 10 mEq of potassium.

Dispersibility of potassium chloride (KCl) is accomplished by microencapsulation and a dispersing agent. The resultant flow characteristics of the KCl microcapsules and the controlled release of K+ ions by the microcapsular membrane are intended to avoid the possibility that excessive amounts of KCl can be localized at any point on the mucosa of the gastrointestinal tract.

Each crystal of KCl is microencapsulated by a patented process with an insoluble polymeric coating which functions as a semi-permeable membrane; it allows for the controlled release of potassium and chloride ions over an eight-to-ten-hour period. Fluids pass through the membrane and gradually dissolve the potassium chloride within the micro-capsules. The resulting potassium chloride solution slowly diffuses outward through the membrane. Micro-K® and Micro-K® 10 are electrolyte replenishers. The chemical name of the active ingredient is potassium chloride and the structural formula is KCl. Potassium chloride USP occurs as a white, granular powder or as colorless crystals. It is odorless and has a saline taste. Its solutions are neutral to litmus. It is freely soluble in water and insoluble in alcohol.

The inactive ingredients are edible ink, ethylcellulose, FD&C blue #2 aluminum lake, FD&C yellow #6, gelatin, magnesium stearate, sodium lauryl sulfate, titanium dioxide. May contain FD&C red #40 and yellow #6 aluminum lakes.

Last updated on RxList: 6/19/2007

BECAUSE OF REPORTS OF INTESTINAL AND GASTRIC ULCERATION AND BLEEDING WITH CONTROLLED-RELEASE POTASSIUM CHLORIDE PREPARATIONS, THESE DRUGS SHOULD BE RESERVED FOR THOSE PATIENTS WHO CANNOT TOLERATE OR REFUSE TO TAKE LIQUID OR EFFERVESCENT POTASSIUM PREPARATIONS OR FOR PATIENTS IN WHOM THERE IS A PROBLEM OF COMPLIANCE WITH THESE PREPARATIONS.

1. For the treatment of patients with hypokalemia with or without metabolic alkalosis, in digitalis intoxications, and in patients with hypokalemic familial periodic paralysis. If hypokalemia is the result of diuretic therapy, consideration should be given to the use of a lower dose of diuretic, which may be sufficient without leading to hypokalemia.
2. For the prevention of hypokalemia in patients who would be at particular risk if hypokalemia were to develop e.g., digitalized patients or patients with significant cardiac arrhythmias, hepatic cirrhosis with ascites, states of aldosterone excess with normal renal function, potassium-losing nephropathy, and certain diarrheal states.

The use of potassium salts in patients receiving diuretics for uncomplicated essential hypertension is often unnecessary when such patients have a normal dietary pattern and when low doses of the diuretic are used. Serum potassium should be checked periodically, however, and if hypokalemia occurs, dietary supplementation with potassium-containing foods may be adequate to control milder cases. In more severe cases, and if dose adjustment of the diuretic is ineffective or unwarranted, supplementation with potassium salts may be indicated.

The usual dietary intake of potassium by the average adult is 50 to 100 mEq per day. Potassium depletion sufficient to cause hypokalemia usually requires the loss of 200 or more mEq of potassium from the total body store.

Dosage must be adjusted to the individual needs of each patients. The dose for the prevention of hypokalemia is typically in the range of 20 mEq per day. Doses of 40 to 100 mEq per day or more are used for the treatment of potassium depletion. Dosage should be divided if more than 20 mEq per day is given such that no more than 20 mEq is given in a single dose. Because of the potential for gastric irritation (see WARNINGS), Micro-K® Extencaps® should be taken with meals and with a full glass of water or other liquid.

Patients who have difficulty swallowing capsules may sprinkle the contents of the capsule onto a spoonful of soft food. The soft food, such as applesauce or pudding, should be swallowed immediately without chewing and followed with a glass of cool water or juice to ensure complete swallowing of the microcapsules. The food used should not be hot and should be soft enough to be swallowed without chewing. Any microcapsule/food mixture should be used immediately and not stored for future use.

Micro-K® Extencaps® are pale orange capsules monogrammed Micro-K® and "Ther-Rx"/ "010" , each containing 600 mg microencapsulated potassium chloride (equivalent to 8 mEq K) in bottles of 100 (NDC 64011-010-04), 500 (NDC 64011-010-08) and Dis-Co® unit dose packs of 100 (NDC 64011-010-11).

Micro-K® 10 Extencaps® are pale orange and opaque white capsules monogrammed Micro-K® 10 and "Ther-Rx"/"009", each containing 750 mg microencapsulated potassium chloride (equivalent to 10 mEq K) in bottles of 100 (NDC 64011-009-04), 100 Unit-of-Use (NDC 64011-009-21), bottles of 500 (NDC 64011-009-08), and Dis-Co® unit dose packs of 100 (NDC 64011-009-11).

Store at controlled room temperature, between 20° C and 25° C (68° F and 77° F).

Dispense in tight container.

Manufactured by KV Pharmaceutical
for Ther-Rx Corporation., St. Louis, MO 63045
FDA rev date: 8/20/2003

Last updated on RxList: 6/19/2007

One of the most severe adverse effects is hyperkalemia (see CONTRAINDICATIONS, WARNINGS, AND OVERDOSAGE). Gastrointestinal bleeding and ulceration have been reported in patients treated with Micro-K® Extencaps® (see CONTRAINDICATIONS and WARNINGS). In addition to gastrointestinal bleeding and ulceration, perforation and obstruction have been reported in patients treated with other solid KCl dosage forms, and may occur with Micro-K® Extencaps®.

The most common adverse reactions to the oral potassium salts are nausea, vomiting, flatulence, abdominal discomfort, and diarrhea. These symptoms are due to irritation of the gastrointestinal tract and are best managed by taking the dose with meals, or reducing the amount taken at one time. Skin rash has been reported rarely with potassium preparations.

Potassium-sparing diuretics, angiotensin converting enzyme inhibitors (see WARNINGS).

Last updated on RxList: 6/19/2007

Hyperkalemia (see OVERDOSAGE)

In patients with impaired mechanisms for excreting potassium, the administration of potassium salts can produce hyperkalemia and cardiac arrest. This occurs most commonly in patients given potassium by the intravenous route but may also occur in patients given potassium orally. Potentially fatal hyperkalmia can develop rapidly and be asymptomatic. The use of potassium salts in patients with chronic renal disease, or any other condition which impairs potassium excretion, requires particularly careful monitoring of the serum potassium concentration and appropriate dosage adjustments.

Interaction with Potassium-Sparing Diuretics

Hypokalemia should not be treated by the concomitant administration of potassium salts and a potassium-sparing diuretic (e.g., spironolactone, triamterene, or amiloride), since the simultaneous administration of these agents can produce severe hyperkalemia.

Interaction with Angiotensin Converting Enzyme Inhibitors

Angiotensin converting enzyme (ACE) inhibitors (e.g., captopril, enalapril) will produce some potassium retention by inhibiting aldosterone production. Potassium supplements should be given to patients receiving ACE inhibitors only with close monitoring.

Gastrointestinal Lesions

Solid oral dosage forms of potassium chloride can produce ulcerative and/or stenotic lesions of the gastrointestinal tract. Based on spontaneous adverse reaction reports, enteric coated preparations of potassium chloride are associated with an increased frequency of small bowel lesions (40 - 50 per 100,000 patient years) compared to sustained-release wax matrix formulations (less than one per 100,000 patient years). Because of the lack of extensive marketing experience with microencapsulated products, a comparison between such products and wax matrix or enteric coated products is not available. Micro-K® Extencaps® and Micro-K® 10 Extencaps® are microencapsulated capsules formulated to provide a controlled rate of release of microencapsulated potassium chloride and thus to minimize the possibility of high local concentration of potassium near the gastrointestinal wall.

Prospective trials have been conducted in normal human volunteers in which the upper gastrointestinal tract was evaluated by endoscopic inspection before and after one week of solid oral potassium chloride therapy. The ability of this model to predict events occurring in usual clinical practice is unknown. Trials which approximated usual clinical practice did not reveal any clear differences between the wax matrix and microencapsulated dosage forms. In contrast, there was a higher incidence of gastric and duodenal lesions in subjects receiving a high dose of a wax matrix controlled-release formulation under conditions which did not resemble usual or recommended clinical practice (i.e., 96 mEq per day in divided doses of potassium chloride administered to fasted patients, in the presence of an anticholinergic drug to delay gastric emptying). The upper gastrointestinal lesions observed by endoscopy were asymptomatic and were not accompanied by evidence of bleeding (hemoccult testing). The relevance of these findings to the usual conditions (i.e., non-fasting, no anticholinergic agent, smaller doses) under which controlled-release potassium chloride products are used is uncertain; epidemiologic studies have not identified an elevated risk, compared to microencapsulated products, for upper gastrointestinal lesions in patients receiving wax matrix formulations. Micro-K® Extencaps® and Micro-K® 10 Extencaps® should be discontinued immediately and the possibility of ulceration, obstruction or perforation considered if severe vomiting, abdominal pain, distention, or gastrointestinal bleeding occur.

Metabolic Acidosis

Hypokalemia in patients with metabolic acidosis should be treated with an alkalinizing potassium salt such as potassium bicarbonate, potassium citrate, potassium acetate, or potassium gluconate.

General The diagnosis of potassium depletion is ordinarily made by demonstrating hypokalemia in a patient with a clinical history suggesting some cause for potassium depletion. In interpreting the serum potassium level, the physician should bear in mind that acute alkalosis per se can produce hypokalemia in the absence of a deficit in total body potassium, while acute acidosis per se can increase the serum potassium concentration into the normal range even in the presence of a reduced total body potassium. The treatment of potassium depletion, particularly in the presence of cardiac disease, renal disease, or acidosis, requires careful attention to acid-base balance and appropriate monitoring of serum electrolytes, the electrocardiogram, and the clinical status of the patient.

Laboratory Tests

Regular serum potassium determinations are recommended, especially in patients with renal insufficiency or diabetic nephropathy. When blood is drawn for analysis of plasma potassium it is important to recognize that artifactual elevations can occur after improper venipuncture technique or as a result of in vitro hemolysis of the sample.

Carcinogenesis, mutagenesis, impairment of fertility

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

Pregnancy: Teratogenic Effects: Category C

Animal reproduction studies have not been conducted with Micro-K®. It is unlikely that potassium supplementation that does not lead to hyperkalemia would have an adverse effect on the fetus or would affect reproductive capacity.

Nursing Mothers

The normal potassium ion content of human milk is about 13 mEq per liter. Since oral potassium becomes part of the body potassium pool, so long as body potassium is not excessive, the contribution of potassium chloride supplementation should have little or no effect on the level in human milk.

Pediatric Use

Safety and effectiveness in pediatric patients have not been established.

Geriatric Use

Clinical studies of Potassium Chloride Extended-release Capsules 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.

Last updated on RxList: 6/19/2007

The administration of oral potassium salts to persons with normal excretory mechanisms for potassium rarely causes serious hyperkalemia. However, if excretory mechanisms are impaired or if potassium is administered too rapidly intravenously, 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 (6.5-8.0 mEq/L) and characteristic electrocardiographic changes (peaking of T-waves, loss of P-waves, depression of ST segment, and prolongation of the QT interval). Late manifestations include muscle paralysis and cardiovascular collapse from cardiac arrest (9-12 mEq/L).

Treatment measures for hyperkalemia include the following: (1) elimination of foods and medications containing potassium and of any agents with potassium-sparing properties; (2) intravenous administration of 300 to 500 mL/hr of 10% dextrose solution containing 10 to 20 units of crystalline insulin per 1,000 mL; (3) correction of acidosis, if present, with intravenous sodium bicarbonate; (4) 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.

Potassium supplements are contraindicated in patients with hyperkalemia since a further increase in serum potassium concentration in such patients can produce cardiac arrest. Hyperkalemia may complicate any of the following conditions: chronic renal failure, systemic acidosis such as diabetic acidosis, acute dehydration, extensive tissue breakdown as in severe burns, adrenal insufficiency, or the administration of a potassium-sparing diuretic (e.g., spironolactone, triamterene, amiloride) (see OVERDOSAGE).

Controlled-release formulations of potassium chloride have produced esophageal ulceration in certain cardiac patients with esophageal compression due to an enlarged left atrium. Potassium supplementation, when indicated in such patients, should be given as a liquid preparation.

All solid oral dosage forms of potassium chloride are contraindicated in any patient in whom there is structural, pathological (e.g., diabetic gastroparesis) or pharmacologic (use of anticholinergic agents or other agents with anticholineric properties at sufficient doses to exert anticholinergic effects) cause for arrest or delay in capsule passage through the gastrointestinal tract.

Last updated on RxList: 6/19/2007

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 to 160 mEq per liter. The normal adult plasma concentration is 3.5 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.

Potassium depletion will occur whenever the rate of potassium loss through renal excretion and/or loss from the gastrointestinal tract exceeds the rate of potassium intake. Such depletion usually develops slowly as a consequence of therapy with diuretics, primary or secondary hyperaldosteronisms, diabetic ketoacidosis, or inadequate replacement of potassium in patients on prolonged parenteral nutrition. Depletion can develop rapidly with severe diarrhea, especially if associated with vomiting. Potassium depletion due to these causes is usually accompanied by a concomitant loss of chloride and is manifested by hypokalemia and metabolic alkalosis. Potassium depletion may produce weakness, fatigue, disturbances of cardiac rhythm (primarily ectopic beats), prominent U-waves in the electrocardiogram, and in advanced cases, flaccid paralysis and/or impaired ability to concentrate urine.

If potassium depletion associated with metabolic alkalosis cannot be managed by correcting the fundamental cause of the deficiency, e.g., where the patient requires long-term diuretic therapy, supplemental potassium in the form of high potassium food or potassium chloride may be able to restore normal potassium levels.

In rare circumstances (e.g., patients with renal tubular acidosis) potassium depletion may be associated with metabolic acidosis and hyperchloremia. In such patients potassium replacement should be accomplished with potassium salts other than the chloride, such as potassium bicarbonate, potassium citrate, potassium acetate, or potassium gluconate.

Last updated on RxList: 6/19/2007

Physicians should consider reminding the patient of the following: To take each dose with meals and with a full glass of water or other suitable liquid. To take each dose without crushing, chewing, or sucking the capsules. To take this medicine following the frequency and amount prescribed by the physician. This is especially important if the patient is also taking diuretics and/or digitalis preparations. To check with the physician if there is trouble swallowing capsules or if the capsules seem to stick in the throat.

To check with the physician at once if tarry stools or other evidence of gastrointestinal bleeding is noticed.

Last updated on RxList: 6/19/2007

IMPORTANT NOTE: This is a summary and does not contain all possible information about this product. For complete information about this product or your specific health needs, ask your health care professional. Always seek the advice of your health care professional if you have any questions about this product or your medical condition. This information is not intended as individual medical advice and does not substitute for the knowledge and judgment of your health care professional. This information does not contain any assurances that this product is safe, effective, or appropriate for you.

POTASSIUM CHLORIDE - ORAL

(poh-TASS-ee-um KLOR-ide)

USES: This medication is a mineral supplement used to prevent or treat low amounts of potassium in the blood. A normal level of potassium in the blood is important so that your cells, nerves, heart, muscles, and kidneys work properly. Normal blood levels of potassium are usually achieved by eating a well-balanced diet. However, certain situations cause your body to lose potassium faster than you can replace it from your diet. These situations include treatment with certain "water pills" (diuretics), a poor diet, or certain medical conditions (e.g., severe diarrhea especially with vomiting).

HOW TO USE: Take this medication by mouth as directed by your doctor. To prevent stomach upset, take each dose with a meal and a full glass (8 ounces or 240 milliliters) of water unless your doctor directs you otherwise. Do not lie down for 30 minutes after taking this medication. If your total daily dosage is more than 20 milliequivalents, your doctor may direct you to divide the daily dose so that you take smaller amounts of medication several times a day, but do not take more than 20 milliequivalents as a single dose. This will also help to reduce stomach upset.

Take this medication regularly in order to get the most benefit from it. Remember to take it at the same time(s) each day. Dosage is based on your medical condition and response to therapy. Do not increase your dose or take it more often than prescribed. Too much potassium in the blood can cause serious side effects.

Sustained-release capsules and tablets must be swallowed whole. Do not crush, chew, or suck the pills because this may increase side effects.

If you have trouble swallowing the capsules, ask your doctor or pharmacist about certain brands that may be opened up and the contents sprinkled onto a spoonful of cool, soft food such as applesauce or pudding. Swallow the food/medication mixture immediately without chewing. Do not prepare the mixture ahead of time. Drink a glass of cool water after each dose to make sure you swallow all the medication.

Inform your doctor if symptoms of low potassium blood levels (e.g., muscle cramps/weakness, tiredness, irregular heartbeat) persist or worsen.

SIDE EFFECTS: Stomach pain/upset, nausea, vomiting, or diarrhea may occur. See How to Use for ways to reduce stomach upset. If any of these effects persist or worsen, tell your doctor or pharmacist promptly.

For some capsule forms of this medication, an empty capsule shell may appear in your stool. This is harmless.

Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.

Tell your doctor immediately if any of these unlikely but serious side effects occur: difficult/painful swallowing, feeling as if the capsule/tablet is stuck in your throat.

Tell your doctor immediately if any of these rare but very serious side effects occur: vomit that looks like coffee grounds, stomach/abdominal pain or swelling, black/tarry stools.

A very serious allergic reaction to this drug is unlikely, but seek immediate medical attention if it occurs. Symptoms of a serious allergic reaction may include: rash, itching, swelling, severe dizziness, trouble breathing.

This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.

Contact your doctor for medical advice about side effects. The following numbers do not provide medical advice, but in the US you may report side effects to the Food and Drug Administration (FDA) at 1-800-FDA-1088. In Canada, you may call Health Canada at 1-866-234-2345.

PRECAUTIONS: Before taking potassium, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies.

This medication should not be used if you have certain medical conditions. Before using this medicine, consult your doctor or pharmacist if you have: high potassium blood levels, severe kidney disease (e.g., chronic kidney failure, inability to make urine), adrenal gland problems, severe conditions of tissue breakdown (e.g., severe burns, traumatic injury).

Due to rare reports of stomach/intestinal ulcers and bleeding with sustained-release potassium chloride products, the capsules/tablets should be used only in patients who cannot take liquid or effervescent potassium forms. Patients with blockage/narrowing/slowed movement of the esophagus/stomach/intestines (e.g., diabetic gastroparesis, esophageal compression due to an enlarged heart) are at greater risk for these side effects and should use liquid or effervescent potassium forms.

Before using this medication, tell your doctor or pharmacist your medical history, especially of: kidney problems, certain types of heart disease (e.g., atrioventricular block), stomach ulcers.

Kidney function declines as you grow older. This medication is removed by the kidneys. Therefore, elderly people may be more sensitive to the effects of this drug.

This medication should be used only when clearly needed during pregnancy. Discuss the risks and benefits with your doctor.

Potassium passes into breast milk. Consult your doctor before breast-feeding.

DRUG INTERACTIONS: Your healthcare professionals (e.g., doctor or pharmacist) may already be aware of any possible drug interactions and may be monitoring you for it. Do not start, stop or change the dosage of any medicine before checking with them first.

Before taking potassium supplements, check with your doctor if you are taking other medications/products that may also increase the potassium level in your blood. A potassium level in the blood that is too high may cause serious side effects. Follow your doctor's instructions carefully and continue medications for your condition as directed. Keep all medical/laboratory appointments so your doctor can monitor your potassium levels. Consult with your doctor if you are taking any of the following: ACE inhibitors (e.g., captopril, lisinopril), angiotensin receptor blockers (ARBs such as candesartan, losartan), eplerenone, potassium-sparing "water pills" (diuretics such as amiloride, spironolactone, triamterene), salt substitutes containing potassium.

Before using this medication, tell your doctor or pharmacist of all prescription and nonprescription/herbal products you may use, especially of: digoxin, drospirenone, "water pills" (diuretics such as furosemide, hydrochlorothiazide).

Also tell your doctor or pharmacist if you take medications that may slow down the movement of potassium capsules/tablets in your digestive system, possibly increasing the risk of side effects. These drugs include: anticholinergic drugs (e.g., atropine, scopolamine), certain antihistamines (e.g., diphenhydramine), antispasmodic drugs (e.g., dicyclomine, hyoscyamine), certain anti-Parkinson's drugs (e.g., benztropine, trihexyphenidyl), belladonna alkaloids, bladder control drugs (e.g., oxybutynin, tolterodine).

This document does not contain all possible interactions. Therefore, before using this product, tell your doctor or pharmacist of all the products you use. Keep a list of all your medications with you, and share the list with your doctor and pharmacist.

OVERDOSE: If overdose is suspected, contact your local poison control center or emergency room immediately. US residents can call the US national poison hotline at 1-800-222-1222. Canadian residents should call their local poison control center directly. Symptoms of overdose may include irregular heartbeat, muscle weakness, confusion, numbness/tingling of the hands/feet, chest pain.

NOTES: Do not share this medication with others.

Laboratory and/or medical tests (e.g., potassium blood level, kidney function tests) should be performed periodically to monitor your progress or check for side effects. Consult your doctor for more details.

Eat a well-balanced diet. Foods high in potassium include: bananas, oranges, watermelon, cantaloupe, raisins, dates, prunes, avocados, apricots, beans, broccoli, leafy green vegetables, spinach, potatoes, lentils, fish, chicken, turkey, ham, beef, and milk. Consult your doctor or pharmacist regarding your specific dietary plan.

MISSED DOSE: If you miss a dose, take it as soon as you remember. If it is near the time of the next dose, skip the missed dose and resume your usual dosing schedule. Do not double the dose to catch up.

STORAGE: Store at room temperature between 59-86 degrees F (15-30 degrees C) away from light and moisture. Do not store in the bathroom. Keep all medicines away from children and pets.

Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company for more details about how to safely discard your product.

Information last revised July 2008 Copyright(c) 2008 First DataBank, Inc.