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Last reviewed on RxList: 6/19/2007
Please Note: This Brand Name drug is no longer available in the US. (Generic versions may still be available.)
Micro-K Side Effects Center

Medical Editor: John P. Cunha, DO, FACOEP

Last reviewed on RxList 8/8/2016

Micro-K (potassium chloride extended-release) Extencaps are a mineral used to prevent or to treat low blood levels of potassium (hypokalemia). Potassium levels can be low as a result of a disease or from taking certain medicines, or after a prolonged illness with diarrhea or vomiting. The brand name Micro-K is discontinued, but generic versions may be available. Common side effects of Micro-K (potassium chloride extended-release) include:

  • nausea
  • vomiting
  • upset stomach
  • gas
  • diarrhea
  • tingling in your hands or feet
  • appearance of a potassium chloride tablet in your stool

Dosage of Micro-K is individualized. 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. Micro-K may interact with eplerenone, digoxin, quinidine, bronchodilators, ACE inhibitors, or diuretics. Tell your doctor all medications and supplements you use. It is unknown if Micro-K will harm a fetus. Tell your doctor if you are pregnant or plan to become pregnant while using this medication. It is unknown if this drug passes into breast milk or if it could harm a nursing baby. Consult your doctor before breastfeeding.

Our Micro-K (potassium chloride extended-release) Extencaps Side Effects Drug Center provides a comprehensive view of available drug information on the potential side effects when taking this medication.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Micro-K Consumer Information

Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.

Stop using this medication and call your doctor at once if you have any of these serious side effects:

  • confusion, anxiety, feeling like you might pass out;
  • uneven heartbeat;
  • extreme thirst, increased urination;
  • leg discomfort;
  • muscle weakness or limp feeling;
  • numbness or tingly feeling in your hands or feet, or around your mouth;
  • severe stomach pain, ongoing diarrhea or vomiting;
  • black, bloody, or tarry stools; or
  • coughing up blood or vomit that looks like coffee grounds.

Less serious side effects may include:

  • mild nausea or upset stomach;
  • mild or occasional diarrhea;
  • slight tingling in your hands or feet; or
  • appearance of a potassium chloride tablet in your stool.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Read the entire detailed patient monograph for Micro-K (Potassium Chloride Extended-Release)

Micro-K Professional Information


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 (potassium chloride extended-release) ® 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 (potassium chloride extended-release) ® 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.

Read the entire FDA prescribing information for Micro-K (Potassium Chloride Extended-Release)

Related Resources for Micro-K

Read the Micro-K User Reviews »

© Micro-K Patient Information is supplied by Cerner Multum, Inc. and Micro-K Consumer information is supplied by First Databank, Inc., used under license and subject to their respective copyrights.

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