Ionolyte

What it is

Ionolyte is an injection for intravenous infusion containing sodium chloride, sodium acetate trihydrate, potassium chloride and magnesium chloride.

Approved indications

— Acute hypomagnesaemia — Prevention of hypomagnesaemia in patients receiving total parenteral nutrition

Dosing overview

Ionolyte is administered intravenously, usually by slow intravenous infusion, diluted in glucose 5%. The maximum dose is 1.9 grams of magnesium chloride anhydrous (40 mEq of magnesium) diluted with 250 mL of 5% glucose and infused at a rate not to exceed 3 mL per minute. The total adult daily dose should not exceed 18.7 grams of magnesium chloride anhydrous per day.

Key safety warnings

Respiration rate should be determined and should be at least 16 per minute prior to each dose, as respiratory depression is the most critical side effect of the medication. Urine output should be monitored and should be at least 100 mL during the four hours preceding dosing to ensure adequate excretion of magnesium. The patellar reflex should be tested prior to administering repeat doses, as suppression of the reflex is an indication of magnesium intoxication. Excessive administration of magnesium chloride may result in hypermagnesaemia, which may include signs of nausea, vomiting, flushing, hypotension, muscle weakness, muscle paralysis, blurred or double vision, central nervous system depression and loss of reflexes. More severe hypermagnesaemia may result in respiratory depression, respiratory paralysis, renal failure, coma, cardiac arrhythmias and cardiac arrest. Magnesium may precipitate an acute myasthenic crisis. Concurrent use of magnesium salts and central nervous system depressant drugs may result in an enhanced central nervous system depressant effect.

Contraindications

Magnesium is contraindicated in patients with heart block, since magnesium may exacerbate this condition. Magnesium is contraindicated in patients with renal failure (creatinine clearance less than 20 mL/min), since there is an increased risk of hypermagnesaemia in these patients. Magnesium chloride should not be given to a pregnant woman within two hours preceding delivery, as there is a risk of respiratory depression due to hypermagnesaemia in the neonate. Magnesium chloride is not recommended in lactating patients.

Regulatory history

DBL Magnesium Chloride Concentrated Injection received initial approval on 08 October 1991. Ionolyte was first listed on the ARTG on 09 May 2014 in two strengths (500 mL and 1000 mL Freeflex bags).