Applies to potassium chloride: oral tablet extended release. Other dosage forms:

• oral capsule extended release
• intravenous solution
• oral packet, oral solution

Serious side effects of Potassium chloride

WARNING/CAUTION: Even though it may be rare, some people may have very bad and sometimes deadly side effects when taking a drug. Tell your doctor or get medical help right away if you have any of the following signs or symptoms that may be related to a very bad side effect:

• Signs of an allergic reaction, like rash; hives; itching; red, swollen, blistered, or peeling skin with or without fever; wheezing; tightness in the chest or throat; trouble breathing, swallowing, or talking; unusual hoarseness; or swelling of the mouth, face, lips, tongue, or throat.
• Signs of a high potassium level like a heartbeat that does not feel normal; change in thinking clearly and with logic; feeling weak, lightheaded, or dizzy; feel like passing out; numbness or tingling; or shortness of breath.
• Slow heartbeat.
• Chest pain or pressure.
• Signs of bowel problems like black, tarry, or bloody stools; fever; mucus in the stools; throwing up blood or throw up that looks like coffee grounds; or very bad stomach pain, constipation, or diarrhea.
• Swelling of belly.

Other side effects of Potassium chloride

All drugs may cause side effects. However, many people have no side effects or only have minor side effects. Call your doctor or get medical help if any of these side effects or any other side effects bother you or do not go away:

• Stomach pain or diarrhea.
• Upset stomach or throwing up.
• Gas.
• Some products of potassium are in a wax matrix; you may see this in stool. The potassium has been taken into the body, but the wax has not.

These are not all of the side effects that may occur. If you have questions about side effects, call your doctor. Call your doctor for medical advice about side effects.

You may report side effects to the FDA at 1-800-332-1088. You may also report side effects at https://www.fda.gov/medwatch.

For Healthcare Professionals

Applies to potassium chloride: compounding powder, intravenous solution, oral capsule extended release, oral granule extended release, oral liquid, oral powder for reconstitution, oral tablet, oral tablet extended release.

Metabolic

Hyperkalemia can cause muscle weakness, paresthesia of the extremities, listlessness, mental confusion, flaccid paralysis, cold skin, grey pallor, peripheral vascular collapse, fall in blood pressure, paralysis, cardiac arrhythmias, and heart block. Electrocardiogram abnormalities include disappearance of the P-wave, widening and slurring of QRS complex, changes of the S-T segment, tall peaked T-waves. At extremely high concentrations (8 to 11 mmol/L) may cause death from cardiac depression, arrhythmias, or arrest.^[Ref]

Frequency not reported: Hyperkalemia (including cardiac arrest as a manifestation), hypervolemia, hyponatremia and hyponatremic encephalopathy, hypokalemia^[Ref]

Gastrointestinal

Frequency not reported: Nausea, vomiting, flatulence, abdominal pain/discomfort, diarrhea, obstruction, bleeding, ulceration, perforation, gastrointestinal hemorrhage, local irritation of the mucosa

Postmarketing reports: Delayed intestinal transit^[Ref]

Local

Frequency not reported: Injection site pain, injection site phlebitis, infection at injection site, venous thrombosis extending from site of injection, extravasation^[Ref]

Cardiovascular

Frequency not reported: Cardiac arrhythmias, cardiac arrest^[Ref]

Dermatologic

Rare (less than 0.1%): Skin rash

Frequency not reported: Urticaria, pruritus^[Ref]

Other

Frequency not reported: Febrile response^[Ref]