Klor-Con is a brand-name prescription medication containing potassium chloride, used to treat or prevent low potassium levels in the blood. It’s one of the most commonly prescribed potassium supplements in the United States, typically given to people whose potassium levels can’t be managed through diet alone.
Why Klor-Con Is Prescribed
Klor-Con treats a condition called hypokalemia, which means your blood potassium has dropped below the normal range of 3.5 to 5.0 milliequivalents per liter (mEq/L). Low potassium is surprisingly common, and most people who take Klor-Con are on it because another medication, often a diuretic (water pill) used for blood pressure or heart failure, is flushing potassium out through the kidneys faster than the body can replace it.
Potassium is essential for nerve signaling, muscle contraction (including your heartbeat), and kidney function. Your cells maintain potassium at concentrations roughly 30 to 40 times higher inside than outside, and even small shifts in blood levels can cause noticeable symptoms like muscle weakness, cramps, fatigue, or irregular heartbeats. Klor-Con is prescribed when eating more potassium-rich foods (bananas, potatoes, leafy greens) isn’t enough to close the gap.
Available Forms and Strengths
Klor-Con comes in two main forms: extended-release tablets and a powder that dissolves in liquid. The tablets are the most widely prescribed version and are sold under several product names based on their strength:
- Klor-Con M10: 750 mg of potassium chloride (10 mEq of potassium), white oblong tablet stamped “KC M10”
- Klor-Con M15: 1,125 mg of potassium chloride (15 mEq of potassium), white oblong tablet stamped “M 15,” scored so it can be split
- Klor-Con M20: 1,500 mg of potassium chloride (20 mEq of potassium), white oblong tablet stamped “KC M20,” also scored
The tablets use a microencapsulated design, meaning the potassium chloride is packed into tiny coated particles that release slowly as the tablet breaks down. This extended-release approach reduces stomach irritation compared to liquid potassium supplements, which deliver the full dose at once. The powder form is mixed into water or juice and taken as a drink, which some people find easier to tolerate.
How to Take It
Klor-Con extended-release tablets should always be taken with a meal and a full glass of water. Taking them on an empty stomach increases the risk of nausea and stomach irritation. You need to swallow the tablets whole. Do not crush, chew, or suck on them, because breaking the extended-release coating releases too much potassium at once, which can irritate the lining of your stomach or intestines.
If you have trouble swallowing large tablets, the scored M15 and M20 versions can be split in half along the score line. Some people also ask about the powder form as an alternative, which is dissolved in liquid before drinking.
Common Side Effects
The most frequently reported side effects are digestive: nausea, vomiting, gas, stomach discomfort, and diarrhea. These tend to improve when you take the medication with food and plenty of water. If stomach symptoms persist, your prescriber may switch you to a different form or adjust timing.
The more serious risk with any potassium supplement is getting too much potassium in your blood, a condition called hyperkalemia. This is more likely if you have kidney problems, since the kidneys are responsible for clearing excess potassium. Hyperkalemia often produces no obvious symptoms at first. It typically shows up on blood work or an electrocardiogram before you feel anything. At higher levels (above 6.5 mEq/L), it can cause changes in heart rhythm. At very high levels (9 to 12 mEq/L), it can lead to muscle paralysis and potentially dangerous cardiac events. This is why your prescriber will order periodic blood tests to check your potassium level while you’re on the medication.
Medications That Raise Your Risk
Several types of medications can cause potassium to build up when combined with Klor-Con. Potassium-sparing diuretics (the kind of water pill that does not flush out potassium) are the most well-known interaction, because taking extra potassium on top of a drug that’s already conserving it can push levels too high. ACE inhibitors and ARBs, two common classes of blood pressure medication, also tend to raise potassium levels on their own and can compound the effect.
If you’re on any of these medications, your prescriber is likely already aware of the interaction and monitoring your bloodwork accordingly. The key thing on your end is to avoid adding over-the-counter potassium supplements or high-potassium salt substitutes without checking first, since those can tip the balance unexpectedly.
Why Potassium Levels Matter
Your body keeps potassium within a narrow range for good reason. Inside your cells, potassium concentrations sit around 150 to 160 mEq/L, while blood plasma stays between 3.5 and 5 mEq/L. That steep difference across cell membranes is what allows your nerves to fire and your muscles to contract. When blood potassium drops too low, you may notice muscle cramps, weakness, constipation, or heart palpitations. When it climbs too high, the electrical signals controlling your heart can become unstable.
Klor-Con’s job is straightforward: replace the potassium your body is losing and keep blood levels in that safe 3.5 to 5.0 range. For most people, it does this effectively with minimal side effects, as long as it’s taken correctly and monitored with routine blood work.