Side Effect: Low Blood Magnesium (hypomagnesemia)

What is Low Blood Magnesium (hypomagnesemia)?

Low blood magnesium, or hypomagnesemia is a condition where the level of magnesium in the blood is below normal range. A level below 1.8 mg/dL is considered low.

What does Low Blood Magnesium (hypomagnesemia) look like?

Magnesium is an electrolyte that is important for many bodily functions including energy metabolism, protein synthesis and neuromuscular function. When magnesium levels drop too low, it can cause muscle weakness, changes in mood, seizures, cardiac arrhythmias, and tremors. Low blood potassium, or hypokalemia, can also happen when the blood magnesium is too low.

Who gets Low Blood Magnesium (hypomagnesemia)?

There are many causes of low blood magnesium. Some people may be at higher risk for low blood magnesium:

• Alcohol use disorder
• Chronic diarrhea (Crohn disease, ulcerative colitis)
• Inability to absorb magnesium
• Bowel surgery
• Gastric bypass surgery
• Certain genetic disorders
• Pancreatitis
• Burns
• Proton pump inhibitors: omeprazole (Prilosec®), pantoprazole (Protonix®), esomeprazole (Nexium®)
• Thiazide and thiazide-like diuretics: hydrochlorothiazide (HCTZ), metolazone (Zaroxolyn®, chlorthalidone (Thalitone®)
• Loop diuretics, also may be called “water pills”: furosemide (Lasix®), torsemide (Demadex®), bumetanide (Bumex®)
• Aminoglycoside antibiotics: amikacin, gentamicin, tobramycin
• Amphotericin B (Ambisome®)
• Foscarnet (Foscavir®)

Patients with cancer are at an increased risk of low blood magnesium due to the effects of cancer and its treatment. Some of the causes of low blood magnesium in patients with cancer include:

• Loss of magnesium through urine, sweat or stool
• Low magnesium in your diet
• Poor nutrition
• Parenteral nutrition
• Radiation to the abdomen or pelvis affecting magnesium absorption
• Kidney damage from cancer treatment
• Platinum therapy: cisplatin (Platinol®), carboplatin (Paraplatin®)
• EGFR inhibitors: cetuximab (Erbitux®), panitumumab (Vectibix®)
• EGFR tyrosine kinase inhibitors: afatinib (Gilotrif®), erlotinib (Tarceva®), gefitinib (Iressa®)
• Irinotecan
• HER2 inhibitors: Pertuzumab (Perjeta®, Phesgo®)
• Calcineurin inhibitors: cyclosporine (Sandimmune®, Neoral®, Gengraf®), tacrolimus (Prograf®)
• Anthracyclines: pegylated liposomal doxorubicin (Doxil®)
• Ifosfamide (Ifex®)
• Carfilzomib (Kyprolis®)

How to prevent Low Blood Magnesium (hypomagnesemia)

Magnesium is in a wide variety of plant and animal foods. To prevent low blood magnesium, it is important to maintain a healthy diet that includes a variety of foods such as leafy green vegetables, nuts and seeds, whole grains and seafood. People who are at risk of low blood magnesium due to certain medical conditions should also be monitored regularly by their healthcare provider to ensure that their magnesium levels remain within normal range.

How to treat Low Blood Magnesium (hypomagnesemia)

The main goal of treatment is to prevent or treat life-threatening complications and replace the magnesium that has been lost with intravenous (IV) or oral magnesium. In some cases, if magnesium is low, the potassium level in the blood may also be low. If potassium in the blood is also low, IV or oral potassium may be given.