Your doctor may recommend treatment with a magnesium infusion if you experience convulsions or have unusually low levels of magnesium in your blood. This magnesium supplement is administered by a medical professional as an injection into a vein in your arm. Talk with your doctor about the side effects of a magnesium infusion before receiving this form of treatment.

Flushing or Sweating

An infusion of magnesium may cause excessive sweating or flushing as side effects of treatment, RxList warns. You may notice that the skin across your body appears unusually pink or red in color and is warm or moist to the touch. When you sweat profusely, your clothing may appear wet or damp. These side effects of a magnesium infusion are temporary and typically subside within a few hours of treatment.

Low Blood Pressure

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This type of magnesium treatment may lower your blood pressure, Drugs.com explains. Unusually low blood pressure, called hypotension, may result in side effects of dizziness, fatigue or headache. If you experience sensations of dizziness or lightheadedness during or following a magnesium infusion, remain seated until such sensations pass. Attempting to stand or move about while you are dizzy may increase your risk of tripping or falling down.

Breathing Difficulties

Breathing difficulties may arise as a side effect of a magnesium infusion. Tell your doctor immediately if you experience shortness of breath, wheezing or chest pain during or following receipt of this magnesium treatment. Severe breathing problems may also exacerbate hypotension symptoms, such as dizziness, confusion or fatigue.

Hypothermia

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Your body's normal temperature may decrease as a side effect of a magnesium infusion. A low body temperature, also called hypothermia, may cause side effects of nausea, vomiting, poor coordination, dizziness, fatigue or confusion, MayoClinic.com explains. Your skin may also feel unusually cool or you may begin shivering. Seek prompt medical care if you develop symptoms of hypothermia after receiving a magnesium infusion.