Potassium Phosphate-Sodium Acid Phosphate

Potassium Phosphate-Sodium Acid Phosphate is a combination medication used for the treatment of hypophosphatemia and low urinary phosphate.

• Potassium Phosphate-Sodium Acid Phosphate is available under various brand names: K-Phos M.F., K-Phos No. 2, K-Phos Neutral, Neutra-Phos, Uro-KP Neutral

Common side effects of Potassium Phosphate-Sodium Acid Phosphate include:

• nausea,
• vomiting,
• stomach pain,
• diarrhea,
• bone or joint pain,
• headache,
• dizziness,
• tiredness,
• muscle pain or weakness,
• increased thirst, and
• numbness or tingly feeling

Serious side effects of Potassium Phosphate-Sodium Acid Phosphate include:

• severe or ongoing diarrhea,
• seizures,
• shortness of breath,
• little or no urinating,
• painful or difficult urination,
• swelling in the feet or ankles,
• tiredness, and
• shortness of breath

Rare side effects of Potassium Phosphate-Sodium Acid Phosphate include:

• none

Seek medical care or call 911 at once if you have the following serious side effects:

• Severe headache, confusion, slurred speech, arm or leg weakness, trouble walking, loss of coordination, feeling unsteady, very stiff muscles, high fever, profuse sweating, or tremors;
• Serious eye symptoms such as sudden vision loss, blurred vision, tunnel vision, eye pain or swelling, or seeing halos around lights;
• Serious heart symptoms include fast, irregular, or pounding heartbeats; fluttering in the chest; shortness of breath; sudden dizziness, lightheadedness, or passing out.

This is not a complete list of side effects and other serious side effects or health problems that may occur because of the use of this drug. Call your doctor for medical advice about serious side effects or adverse reactions. You may report side effects or health problems to FDA at 1-800-FDA-1088.

Adult and pediatric dosage

Tablet

• 126 mg/67 mg
• 250 mg/298 mg
• 250 mg/160 mg

Hypophosphatemia

Adult dosage

• K-Phos Neutral: 1-2 tablets orally every 4 hours
• Phos-NaK: 1 packet mixed with 75 mL water or juice

Pediatric dosage

• Aged below 4 years: Safety and efficacy not established
• Aged above 4 years: K-Phos Neutral, 1 tablet orally every 6 hours; Phos-NaK, 1 packet orally every 6 hours mixed with 75 mL water or juice

Low Urinary Phosphate

Adult dosage

• 1-2 tablets orally every 6 hours

Pediatric dosage

• Aged below 4 years: Safety and efficacy not established
• Aged above 4 years: 1-2 tablets orally every 6 hours

Dosage Considerations – Should be Given as Follows: 

• See “Dosages”

If your medical doctor is using this medicine to treat your pain, your doctor or pharmacist may already be aware of any possible drug interactions and may be monitoring you for them. Do not start, stop, or change the dosage of any medicine before checking with your doctor, health care provider, or pharmacist first.

• Potassium Phosphate-Sodium Acid Phosphate has severe interactions with the following drug:
  • sodium phosphate rectal
• Potassium Phosphate-Sodium Acid Phosphate has serious interactions with the following drugs:
  • baloxavir marboxil
  • erdafitinib
  • potassium phosphates, IV
• Potassium Phosphate-Sodium Acid Phosphate has moderate interactions with the following drugs:
  • deflazacort
  • dextroamphetamine
  • lisdexamfetamine
  • magnesium supplement
  • methamphetamine
  • methylenedioxymethamphetamine
  • omadacycline
  • potassium iodide
  • pseudoephedrine
  • sarecycline
• Potassium Phosphate-Sodium Acid Phosphate has minor interactions with no other drugs.

This information does not contain all possible interactions or adverse effects. Visit the RxList Drug Interaction Checker for any drug interactions. Therefore, before using this product, tell your doctor or pharmacist about all your products. Keep a list of all your medications with you and share this information with your doctor and pharmacist. Check with your healthcare professional or doctor for additional medical advice, or if you have health questions or concerns.

Contraindications

• Patients with infected phosphate stones
• Severe renal impairment
• Hyperphosphatemia

Effects of drug abuse

• None

Short-Term Effects

• See “What Are Side Effects Associated with Using Potassium Phosphate-Sodium Acid Phosphate?”

Long-Term Effects

• See “What Are Side Effects Associated with Using Potassium Phosphate-Sodium Acid Phosphate?”

Cautions

• Patient may experience a mild laxative effect within first few days of therapy; if laxative effect persists, reduce the dose or discontinue use until diarrhea improves
• Use caution in cardiac disease, especially in digitalized patients with heart failure, patients with hypertension, renal calculi, renal impairment, rickets, adrenal insufficiency, acute dehydration, renal disease, extensive tissue breakdown, as in severe burns, myotonia congenita, cirrhosis of liver, edema, hypertension, hypoparathyroidism, acute pancreatitis, hepatic impairment, hypernatremia, metabolic alkalosis

Pregnancy & Lactation

• Use with caution if benefits outweigh risks during pregnancy
• Lactation
  • Unknown whether drug is distributed in breast milk; caution is advised