From the Guidelines
Epsom salt toxicity due to excessive ingestion or absorption through the skin can lead to magnesium toxicity, with signs including nausea, vomiting, abdominal pain, diarrhea, confusion, weakness, irregular heartbeat, low blood pressure, respiratory depression, and seizures. The primary concern with Epsom salt toxicity is magnesium toxicity, as Epsom salt is magnesium sulfate. People with kidney disease are at higher risk because they cannot efficiently clear excess magnesium 1.
Signs and Symptoms of Magnesium Toxicity
- Neurological symptoms: muscular weakness, paralysis, ataxia, drowsiness, and confusion
- Cardiovascular symptoms: vasodilation, hypotension, bradycardia, cardiac arrhythmias, and cardiorespiratory arrest
- Gastrointestinal symptoms: nausea and vomiting
- Other signs: loss of tendon reflexes, sedation, severe muscular weakness, respiratory depression, skin changes (flushing), and electrolyte/fluid abnormalities (hypophosphatemia, hyperosmolar dehydration) 1.
Management of Magnesium Toxicity
Administration of calcium (calcium chloride or calcium gluconate) may be considered during cardiac arrest associated with hypermagnesemia 1. If you suspect Epsom salt toxicity, seek immediate medical attention, as toxicity can occur because excessive magnesium interferes with nerve transmission, muscle function, and cardiac activity by competing with calcium, leading to the symptoms observed. Normal therapeutic use (soaking in a bath with 1-2 cups of Epsom salt for 12-15 minutes) is generally safe for most people, but when taken orally as a laxative, follow package directions (typically 2-4 teaspoons in water) and don't exceed recommended doses.
From the FDA Drug Label
Magnesium intoxication is manifested by a sharp drop in blood pressure and respiratory paralysis. Disappearance of the patellar reflex is a useful clinical sign to detect the onset of magnesium intoxication. Clinical indications of a safe dosage regimen include the presence of the patellar reflex (knee jerk) and absence of respiratory depression (approximately 16 breaths or more/min). The strength of the deep tendon reflexes begins to diminish when magnesium levels exceed 4 mEq/L. Reflexes may be absent at 10 mEq magnesium/L, where respiratory paralysis is a potential hazard.
The signs of magnesium toxicity due to overdose include:
- Sharp drop in blood pressure
- Respiratory paralysis
- Disappearance of the patellar reflex
- Diminishment of deep tendon reflexes when magnesium levels exceed 4 mEq/L
- Respiratory depression (less than 16 breaths/min) 2 2
From the Research
Signs of Magnesium Toxicity
The signs of magnesium toxicity due to Epsom salt overdose include:
- Limb weakness 3, 4, 5
- Vomiting 3
- Confusion 3
- Altered mental status 4, 5
- Respiratory depression 4
- Bradycardia 3, 4
- Hypotension 4
- Cardiac arrest 3, 5, 6
Severity and Treatment
The severity of magnesium toxicity does not always correlate with serum magnesium values, but the risk of cardiac arrest increases with concentrations >6 mmol/l 3. Initial treatment is supportive, and dialysis should be considered when life-threatening features or renal impairment are present 3, 4, 5. Calcium gluconate and intravenous fluids with furosemide may be given as an adjunct to treatment 4.
Hypermagnesemia
Hypermagnesemia is an often overlooked electrolyte abnormality that can have severe consequences, including cardiac arrest and respiratory depression 4. It is usually associated with renal failure, but can also occur in individuals with normal renal function, especially in cases of overdose 3, 5.
Epsom Salt Overdose
Epsom salt overdose can lead to severe hypermagnesemia, which can be fatal if left untreated 5. The use of Epsom salt as a laxative or for other purposes can lead to accidental or intentional overdose, highlighting the need for caution and awareness of the potential risks 3, 4, 5.