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Hyperkalemia (high potassium in the blood)

Also called: Hyperkalemia, high potassium

Too much potassium in the blood, often from kidney disease or some medicines. It can cause dangerous heart rhythms.

DangerHeart rhythm
Common causesKidney disease, some medicines

Overview

High potassium often has no symptoms until it affects the heart.

Salt substitutes contain potassium.

Symptoms

Common signs:

  • Often no symptoms

Less common

  • Weakness
  • Irregular heartbeat

Look up a symptom: Muscle weakness in arms or legs

When to get medical care

Call 911Chest pain, fainting, or very irregular heartbeat.
Get care todayWeakness with known high potassium.
See a doctor soonHigh potassium.

Causes

Kidneys, medicines.

Does it spread or run in families?

  • It isn't contagious. You can't catch it from someone else.

Who is more likely to get it

  • Kidney disease

Possible complications

Diagnosis

A clinician asks about your symptoms and may order tests.

The exam

A physical exam.

Tests

Tests, if needed:

  • Blood test:
  • ECG:

Treatment

Treatment depends on the cause and how severe it is.

Self-care

  • Follow a low-potassium diet if told
  • Review medicines

Which doctor treats this

  • Start with your primary care provider (family doctor or internist).
  • They may send you to a nephrologist (kidney doctor).

Children, pregnancy, and older adults

  • People with kidney disease: Higher risk.

Pregnancy and breastfeeding

  • If you're pregnant or planning to be, tell your prenatal provider about this condition.
  • Don't start or stop any medicine on your own. Some are safe in pregnancy and some need to be changed.
  • Ask before taking any pain reliever. The FDA advises avoiding ibuprofen and naproxen after 20 weeks unless your doctor says to.
  • Breastfeeding: Most medicines are fine, but ask. The NIH LactMed database lists what's known about each one.

Outlook

Treatment lowers potassium quickly.

Getting ready for your visit

Bring a list of your symptoms and medicines.

What to bring

  • A list of your medicines and supplements
  • Notes on when symptoms started and what makes them better or worse

Questions to ask

  • What's causing this?
  • What treatment do you recommend?
  • Should I avoid salt substitutes?

Research studies

Research studies test new ways to find and treat health problems. Some are looking for volunteers. Talk with your doctor before joining one.

Search ClinicalTrials.gov for studies on Hyperkalemia (high potassium in the blood)

Sources

Last updated 2026-11-12.