K-TAB (potassium chloride extended-release tablets)
is a solid oral dosage form of potassium chloride containing 750 mg of potassium
chloride, USP, equivalent to 10 mEq of potassium in a film-coated (not enteric-coated),
wax matrix tablet. This formulation is intended to slow the release of potassium
so that the likelihood of a high localized concentration of potassium chloride
within the gastrointestinal tract is reduced. The expended inert, porous,
wax/polymer matrix is not absorbed and may be excreted intact in the stool.
K-TAB tablets are an electrolyte replenisher. The chemical
name 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.
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 as a consequence
of therapy with diuretics, primary or secondary hyperaldosteronism, 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.
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 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.
INDICATIONS AND USAGE
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 WITH WHOM THERE IS A PROBLEM OF COMPLIANCE WITH THESE PREPARATIONS.
For the treatment of patients with hypokalemia with or without metabolic
alkalosis, in digitalis intoxication, 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.
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.
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.
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, or amiloride (see OVERDOSAGE ).
K-TAB tablets are contraindicated
in patients with known hypersensitivity to any ingredient in this product.
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 anticholinergic
properties at sufficient doses to exert anticholinergic effects) cause for
arrest or delay in tablet passage through the gastrointestinal tract.
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 intravenously,
but may also occur in patients given potassium orally. Potentially fatal
hyperkalemia can develop rapidly and can 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 adjustment.
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.
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. K-TAB tablets consist of a wax matrix formulated to provide
a controlled rate of release potassium chloride and thus to minimize the possibility
of a 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., nonfasting, no
anticholinergic agent, and 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. K-TAB tablets should
be discontinued immediately and the possibility of ulceration, obstruction
or perforation considered if severe vomiting, abdominal pain, distention,
or gastrointestinal bleeding occurs.
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.
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 to within 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.
Information for Patients
Physicians should consider reminding the patient
of the following:
To take each dose with meals
and with a full glass of water or other liquid.
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
To check with the physician
if there is trouble swallowing tablets or if the tablets seem to stick in
To check with the physician at
once if tarry stools or other evidence of gastrointestinal bleeding is noticed.
To take each dose without crushing, chewing or sucking the
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 vitrohemolysis of the sample.
Potassium-sparing diuretics, angiotensin converting
enzyme inhibitors (see WARNINGS).
Carcinogenesis, Mutagenesis, Impairment of Fertility
Carcinogenicity, mutagenicity and fertility studies
in animals have not been performed. Potassium is a normal dietary constituent.
Pregnancy Category C
Animal reproduction studies have not been conducted
with K-TAB tablets. 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.
The normal potassium ion content of human milk is
about 13 mEq per liter. Since oral potassium becomes part of the body potassium
pool, as long as body potassium is not excessive, the contribution of potassium
chloride supplementation should have little or no effect on the level in human
Safety and effectiveness in children have not been
Clinical Studies of K-Tab tablets 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.
One of the most severe adverse effects is hyperkalemia
(see CONTRAINDICATIONS, WARNINGS , and OVERDOSAGE). There also
have been reports of upper and lower gastrointestinal conditions including
obstruction, bleeding, ulceration, and perforation (see CONTRAINDICATIONSand WARNINGS).
The most common adverse reactions to oral potassium salts
are nausea, vomiting, flatulence, abdominal pain/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
Skin rash has been reported rarely.
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 intravenous administration
is too rapid, 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 P-waves, depression
of S-T segments, and prolongation of the QT intervals). Late manifestations
include muscle paralysis and cardiovascular collapse from cardiac arrest (9-12
Treatment measures for hyperkalemia include
Elimination of foods and medications containing potassium and of any
agents with potassium-sparing properties;
Intravenous administration of 300 to 500 mL/hr of 10% dextrose solution
containing 10-20 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, lowering the serum potassium
concentration too rapidly 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
DOSAGE AND ADMINISTRATION
The usual dietary potassium intake 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
Dosage must be adjusted to the individual
needs of each patient. The dose for the prevention of hypokalemia is typically
in the range of 20 mEq per day. Doses of 40-100 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 mEqis given in a single dose.
K-TAB tablets provide
10 mEq of potassium chloride.
K-TAB tablets should
be taken with meals and with a glass of water or other liquid. This product
should not be taken on an empty stomach because of its potential for gastric
irritation (see WARNINGS).
NOTE:K-TAB tablets are
to be swallowed whole without crushing, chewing or sucking the tablets.
K-TAB (potassium chloride extended-release tablets,
USP) contains 750 mg of potassium chloride (equivalent to 10 mEq). K-TAB
tablets are provided as yellow, ovaloid, extended-release Filmtab® tablets
in bottles of 100 (NDC 0074-7804-13),
1000 (NDC 0074-7804-19) and 5000 (NDC 0074-7804-59) and in ABBO-PAC® unit
dose packages of 100 (NDC 0074-7804-11).
Store below 86°F (30°C).
Filmtab - Film-sealed tablet, Abbott
by: Abbott Pharmaceuticals PR Ltd. Barceloneta, PR 00617 For: Abbott
Laboratories North Chicago, IL 60064
potassium chloride tablet, film coated, extended release