Too much of a good thing? TREATMENT of HYPERkalemia
Last week we discussed potassium supplementation and the treatment of hypokalemia. Even more challenging is when the potassium levels rise excessively, due to chronic kidney disease, heart failure, excessive tissue trauma (burns, etc.) or medications.
Hyperkalemia: serum potassium level greater than 5.5 mEq (mmol)/L. Hyperkalemia is a serious and potentially life-threatening disorder. It can cause: muscle fatigue, weakness, paralysis, nausea and life threatening cardiac arrhythmias.
Drugs noted for causing HYPERkalemia:
- NSAIDS (Ibuprofen, Naproxen, etc)
- Potassium Sparing Diuretics (triamterene, amiloride, spironolactone)
- Angiotensin Converting Enzyme inhibitors (Lisinopril, Enalapril Captopril etc)
- Angiotensin Receptor Blockers (Valsartan, Irbesartan, Losartan etc)
- Trimethoprim (Bactrim-DS)
- Excess doses of potassium supplements
Treatment for hyperkalemia involves three goals, namely restoring normal potassium balance, preventing serious complications, and treating the cause
Treatment for severe hyperkalemia can be broken down into three steps:
1) Antagonizing the effects of potassium on excitable cell membranes
- Calcium gluconate is used to antagonize the effects of potassium on the heart muscle in patients with severe hyperkalemia. NO effect on blood levels of K+
2) Redistributing extracellular potassium into cells
Beta agonists (high-dose nebulized albuterol) help shift potassium from the extracellular fluid to intracellular fluid in patients with severe hyperkalemia.
Insulin can be used to help shift potassium from the extracellular fluid to intracellular fluid in patients with severe hyperkalemia. Give with glucose to prevent hypoglycemia.
3) Enhancing elimination of potassium from the body.
- Diuretics (loop diuretics)
- thiazide diuretics can be used only down to CrCl=40
Sodium polystyrene sulfonate (Kayexalate, Kionex, SPS) -available 1958
Mechanism: ion exchange resin absorbs potassium in the intestinal lumen.
Dose: The average daily adult dose of the resin is 15 g to 60 g. Each gram of resin may bind as much as 1 mEq of potassium and release 1 to 2 mEq of sodium
Side effects: GI disturbance, Constipation, Hypokalemia, Hypocalcemia Hypomagnesemia, Sodium retention, Nausea, Vomiting GI tract ulceration or necrosis, which could lead to perforation.
Avoid in patients on opioid therapy, post op patients, C. dif patients, and patients prone to small or large bowel obstruction.
Use SPS only the following criteria are met:
- Potentially life-threatening hyperkalemia
- Dialysis is not readily available
- Other therapies to like diuretics, or rapid restoration of kidney function have failed or are not possible
Veltassa (patiromer) released October 2015, is the first new treatment for hyperkalemia in 50 years.
Mechanism: is powder form that spherical beads bind to potassium in exchange for calcium, primarily in the colon. The potassium is then excreted from the body fecally.
Limitation of Use: Veltassa® should not be used as an emergency treatment for life threatening hyperkalemia because of its delayed onset of action
Dosage: Administer Veltassa at least 6 hours before or 6 hours after other oral medications. Administer with food. Starting dose of Veltassa is 8.4 grams patiromer once daily. Available in individual packets.
Monitor serum potassium and adjust the dose of Veltassa based on the serum potassium level and the desired target range.
All of the drugs for treatment of hyperkalemia require a hands on approach for mixing and measuring the resins. This is a great opportunity for the independent pharmacist to provide the “hands on” care these complicated patients require.
Lokelma (sodium zirconium cyclosilicate) “ZS-9” released November 2018
Limitation of Use: do not use as an emergency treatment for life-threatening hyperkalemia because of its delayed onset of action.
Mechanism: potassium binder. Sodium zirconium cyclosilicate is a non-absorbed zirconium silicate that preferentially exchanges potassium for hydrogen and sodium. This complex is passed out fecally with bound potassium.
Dosage/Administration: Recommended starting dose is 10 g administered three times a day for up to 48 hours.
- For maintenance treatment, recommended dose is 10 g once daily. (2.1)
- Adjust dose at one-week intervals as needed (by 5 g daily) to obtain desired serum potassium target range
Avoid: patients with severe constipation, bowel obstruction or impaction, including abnormal post-operative bowel motility disorders.
Good things come to those who wait! It took almost 60 years to get a potassium binder than wouldn’t cause bowel necrosis and do more harm than good. Kayexalate (SPS) was first introduced the year I was born in 1958. The two new potassium binders came out the past two years. Veltassa is available as a specialty pharmacy drug. The starting dose for Veltassa, is 8.4grams per day, GoodRx prices it around $900.00 per month. Lokelma is stocked in our warehouse with average wholesale price of $786.00 per month, and is readily available in the community pharmacy practice setting.