Medications That Cause Hypomagnesemia and Hypokalemia
Loop diuretics and thiazide diuretics are the primary medication classes that cause both hypomagnesemia and hypokalemia, with thiazides having a stronger association with hypomagnesemia while both significantly affect potassium levels. 1, 2
Diuretics
Loop Diuretics
- Furosemide, bumetanide, and torasemide can cause hypokalemia and hypomagnesemia through increased urinary excretion of these electrolytes 3
- Loop diuretics are associated with more significant hypokalemia than hypomagnesemia, particularly with higher doses and prolonged use 1
- Risk factors for electrolyte depletion with loop diuretics include:
- Brisk diuresis
- Restricted salt intake
- Presence of cirrhosis
- Concomitant use of corticosteroids or ACTH 1
Thiazide Diuretics
- Hydrochlorothiazide, metolazone, and indapamide are strongly associated with both hypokalemia and hypomagnesemia 3
- Thiazide diuretics are more strongly associated with hypomagnesemia than loop diuretics 4
- Long-term thiazide use (>390 days) significantly increases the risk of hypomagnesemia with an odds ratio of 2.74-3.14 4
- Chlorthalidone has a higher risk of causing hypokalemia compared to hydrochlorothiazide (hazard ratio 3.06) 5
Other Medications
Proton Pump Inhibitors (PPIs)
- Esomeprazole, pantoprazole, omeprazole, and rabeprazole can cause severe hypomagnesemia even after just 1 year of use 6
- PPI-induced hypomagnesemia can lead to secondary hypokalemia through increased renal potassium excretion 6
Other Medications That Affect Electrolytes
- Corticosteroids and ACTH intensify electrolyte depletion, particularly hypokalemia 2
- Digitalis therapy can exaggerate the metabolic effects of hypokalemia 1
- Laxatives (with prolonged use) can contribute to hypokalemia 1
- Licorice in large amounts can cause hypokalemia 1
Clinical Manifestations and Monitoring
Signs and Symptoms
- Symptoms of hypomagnesemia and hypokalemia include:
Monitoring Recommendations
- Regular monitoring of serum electrolytes (potassium, magnesium, sodium) is essential for patients on diuretics 3, 1
- For patients starting diuretic therapy, check electrolytes every 5-7 days initially until values stabilize, then every 3-6 months 3
- Patients on thiazide diuretics should have magnesium levels checked regularly, even though this is not consistently included in hypertension guidelines 3
Prevention and Management
Prevention Strategies
- Combining thiazide diuretics with potassium-sparing agents (spironolactone, amiloride, triamterene) can prevent hypokalemia and hypomagnesemia 4
- Using the lowest effective dose of diuretics can minimize electrolyte disturbances 3
- Potassium-sparing diuretics tend to increase serum and intracellular magnesium content 7
Treatment Approaches
- For hypokalemia: potassium supplementation or increased dietary intake of potassium-rich foods 2
- For hypomagnesemia: oral magnesium supplements for asymptomatic patients; parenteral magnesium for symptomatic patients with severe deficiency (<1.2 mg/dL) 8
- Spironolactone (12.5-50 mg) can be used to prevent excess potassium and magnesium excretion 3
Special Considerations
High-Risk Populations
- Patients with cirrhosis are at increased risk for diuretic-induced electrolyte abnormalities 1
- Elderly patients are more susceptible to severe electrolyte depletion and its consequences 1
- Patients with heart failure may have altered electrolyte balance at baseline, complicating the management of diuretic-induced electrolyte disorders 9