Potassium Phosphate, Monobasic and Sodium Phosphate, Monobasic, Anhydrous

INDICATONS AND USAGE K-PHOS® No. 2 is a highly effective urinary acidifier for use in patients with elevated urinary pH. This product helps keep calcium soluble and reduces odor and rash caused by ammoniacal urine. Also, by acidifying the urine, it increases the antibacterial activity of methenamine mandelate and methenamine hippurate.

This product is contraindicated in patients with infected phosphate stones, in patients with severely impaired renal function (less than 30% of normal) and in the presence of hyperphosphatemia.

General This product contains potassium and sodium and should be used with caution if regulation of these elements is desired. Occasionally, some individuals may experience a mild laxative effect during the first few days of phosphate therapy. If laxation persists to an unpleasant degree, reduce the daily dosage until this effect subsides or, if necessary, discontinue the use of this product. Use of this medication should be carefully considered when the following medical problems exist: Cardiac disease (particularly in digitalized patients), Addison's disease, acute dehydration, extensive tissue breakdown, myotonia congenita, cardiac failure, cirrhosis of the liver or severe hepatic disease, peripheral and pulmonary edema, hypernatremia, hypertension, toxemia of pregnancy, hypoparathyroidism, and acute pancreatitis. Rickets may benefit from phosphate therapy, but caution should be observed. High serum phosphate levels increase the risk of extraskeletal calcification. Information for Patients Patients with kidney stones may pass old stones when phosphate therapy is started and should be warned of this possibility. Patients should be advised to avoid the use of antacids containing aluminum, magnesium, or calcium which may prevent the absorption of phosphate. Laboratory Tests Careful monitoring of renal function and serum calcium, phosphorus, potassium and sodium may be required at periodic intervals during phosphate therapy. Other tests may be warranted in some patients, depending on conditions. Drug Interactions The use of antacids containing magnesium, aluminum, or calcium in conjunction with phosphate preparations may bind the phosphate and prevent its absorption. Concurrent use of antihypertensives, especially diazoxide, guanethidine, hydralazine, methyldopa, or rauwolfia alkaloid; or corticosteroids, especially mineralocorticoids or corticotropin, with sodium phosphate may result in hypernatremia. Potassium-containing medications or potassium-sparing diuretics may cause hyperkalemia when used wi t h potassium phosphate. Patients should have serum potassium level determinations at periodic intervals. Plasma levels of salicylates may be increased since salicylate excretion is decreased in acidified urine. Administration of monobasic phosphates to patients stabilized on salicylates may lead to toxic salicylate levels. Carcinogenesis, Mutagenesis, Impairment of Fertility No long-term or reproduction studies in animals or humans have been performed with K-PHOS® No. 2 to evaluate its carcinogenic, mutagenic, or impairment of fertility potential. Pregnancy Teratogenic Effects Pregnancy Category C Animal reproduction studies have not been conducted with K-PHOS® No. 2. It is also not known whether this product can cause fetal harm when administered to a pregnant woman or can affect reproductive capacity. This product should be given to a pregnant woman only if clearly needed. Nursing Mothers It is not known whether this drug is excreted in human milk. Because many drugs are excreted in human milk, caution should be exercised when this product is administered to a nursing woman.

Gastrointestinal upset (diarrhea, nausea, stomach pain and vomiting) may occur with phosphate therapy. Also, bone and joint pain (possible phosphate-induced osteomalacia) could occur. The following adverse effects may be observed (primarily from sodium or potassium): headaches; dizziness; mental confusion; seizures; weakness or heaviness of legs; unusual tiredness or weakness; muscle cramps; numbness, tingling, pain, or weakness of hands or feet; numbness or tingling around lips; fast or irregular heartbeat; shortness of breath or troubled breathing; swelling of feet or lower legs; unusual weight gain; low urine output; unusual thirst.

The use of antacids containing magnesium, aluminum, or calcium in conjunction with phosphate preparations may bind the phosphate and prevent its absorption. Concurrent use of antihypertensives, especially diazoxide, guanethidine, hydralazine, methyldopa, or rauwolfia alkaloid; or corticosteroids, especially mineralocorticoids or corticotropin, with sodium phosphate may result in hypernatremia. Potassium-containing medications or potassium-sparing diuretics may cause hyperkalemia when used wi t h potassium phosphate. Patients should have serum potassium level determinations at periodic intervals. Plasma levels of salicylates may be increased since salicylate excretion is decreased in acidified urine. Administration of monobasic phosphates to patients stabilized on salicylates may lead to toxic salicylate levels.

Teratogenic Effects Pregnancy Category C Animal reproduction studies have not been conducted with K-PHOS® No. 2. It is also not known whether this product can cause fetal harm when administered to a pregnant woman or can affect reproductive capacity. This product should be given to a pregnant woman only if clearly needed.

It is not known whether this drug is excreted in human milk. Because many drugs are excreted in human milk, caution should be exercised when this product is administered to a nursing woman.