Consumer medicine information

Magnesium Sulfate Heptahydrate 50% Concentrated Injection

Magnesium sulfate heptahydrate

BRAND INFORMATION

Brand name

Phebra Magnesium Sulfate Heptahydrate 50% Injection

Active ingredient

Magnesium sulfate heptahydrate

Schedule

Unscheduled

 

Consumer medicine information (CMI) leaflet

Please read this leaflet carefully before you start using Magnesium Sulfate Heptahydrate 50% Concentrated Injection.

What is in this leaflet

This leaflet answers some common questions about Magnesium Sulfate Heptahydrate 50% Concentrated Injection. It does not contain all the available information. It does not take the place of talking to your doctor.

All medicines have risks and benefits. Your doctor has weighed the risks of you being given Magnesium Sulfate Heptahydrate 50% Concentrated Injection against the benefits they expect it will have for you.

If you have any concerns about being given this medicine, ask your doctor.

Keep this leaflet. You may need to read it again.

What Magnesium Sulfate Heptahydrate 50% Concentrated Injection is used for

Magnesium Sulfate Heptahydrate 50% Concentrated Injection is used to quickly increase the amount of magnesium in your body. Other reasons for treatment with Magnesium Sulfate Heptahydrate 50% Concentrated Injection are:

  • the prevention and treatment of life-threatening seizures associated with high blood pressure during pregnancy
  • low potassium levels in the blood
  • to act as a source of nutrition for a patient fed only by intravenous means.

Magnesium Sulfate Heptahydrate 50% Concentrated Injection works by providing a source of magnesium for your body to use.

Ask your doctor if you have any questions about why this medicine has been prescribed for you. Your doctor may have prescribed Magnesium Sulfate Heptahydrate 50% Concentrated Injection for another reason.

Before you are given Magnesium Sulfate Heptahydrate 50% Concentrated Injection

When you must not be given it

You should not be given Magnesium Sulfate Heptahydrate 50% Concentrated Injection if have an allergy to:

  • any medicine containing magnesium or magnesium sulfate heptahydrate
  • any of the ingredients listed at the end of this leaflet.

Some symptoms of an allergic reaction may include:

  • shortness of breath
  • wheezing or difficulty breathing
  • swelling of the face, lips, tongue, or other parts of the body
  • rash, itching or hives on the skin.

You should not be given Magnesium Sulfate Heptahydrate 50% Concentrated Injection if you are breast-feeding. Magnesium passes into breast milk and there is a possibility your baby may be affected.

You should not be given Magnesium Sulfate Heptahydrate 50% Concentrated Injection if you have slow or irregular heart beat.

You should not be given Magnesium Sulfate Heptahydrate 50% Concentrated Injection if you have kidney disease.

You should not be given Magnesium Sulfate Heptahydrate 50% Concentrated Injection if you have liver disease.

You should not be given Magnesium Sulfate Heptahydrate 50% Concentrated Injection if the solution is discoloured, cloudy, turbid, or a precipitate is present. The solution is normally a clear, colourless solution.

You should not be given Magnesium Sulfate Heptahydrate 50% Concentrated Injection if, when diluted with another solution, it causes the solution to precipitate, become cloudy, turbid, discolour, or particles are visible.

You should not be given Magnesium Sulfate Heptahydrate 50% Concentrated Injection after the expiry date printed on the package or if the packaging is torn or shows signs of tampering. If you are given this medicine after the expiry date has passed, it may not work as well.

If you are not sure whether you should be given this medicine talk to your doctor.

Before you are given it

Tell your doctor if you have allergies to any other medicines, foods, preservatives or dyes.

Tell your doctor if you have or have had any of the following medical conditions:

  • kidney problems
  • liver problems
  • myasthenia gravis, a condition in which the muscles become weak and tire easily.

Tell your doctor if you are pregnant or are experiencing any symptoms of labour. Your doctor can discuss with you the risks and benefits involved. If you have not told your doctor about any of the above, tell him/her before you are given Magnesium Sulfate Heptahydrate 50% Concentrated Injection.

Taking other medicines

Tell your doctor if you are taking any other medicines, including medicines that you buy without a prescription from your pharmacy, supermarket, health food shop, naturopath or herbalist. Some medicines may interfere with magnesium sulfate heptahydrate. These include:

  • medicines used to treat heart failure called cardiac glycosides such as digoxin
  • medicines used to treat heart disease such as nifedipine
  • medicines used as central nervous system depressants
  • medicines used with anaesthetics to relax the muscles called neuromuscular blocking agents.

These medicines may be affected by magnesium sulfate heptahydrate, or may affect how well it works. You may need different amounts of your medicine, or you may need to take different medicines.

Your doctor and pharmacist have more information on medicines to be careful with or avoid while being given Magnesium Sulfate Heptahydrate 50% Concentrated Injection.

How Magnesium Sulfate Heptahydrate 50% Concentrated Injection is given

Magnesium Sulfate Heptahydrate 50% Concentrated Injection must only be given by a doctor or nurse.

Magnesium Sulfate Heptahydrate 50% Concentrated Injection is given by mixing it with other fluids and then infusing it into a vein.

Magnesium Sulfate Heptahydrate 50% Concentrated Injection can also be injected into a muscle.

Your doctor will decide what dose of Magnesium Sulfate Heptahydrate 50% Concentrated Injection you will receive and how long you will receive it for. This depends on your medical condition and other factors, such as your weight.

Sometimes only a single dose of Magnesium Sulfate Heptahydrate 50% Concentrated Injection is required.

If you are given too much (overdose)

Magnesium Sulfate Heptahydrate 50% Concentrated Injection must only be given by a doctor or nurse so an overdose is not likely to occur. Some medical conditions may result in too much magnesium in your blood. Your doctor or nurse will monitor the level of magnesium in your blood.

Symptoms of an overdose are the same as the symptoms of the side effects experiences with this medicine but may be more severe. The symptoms of a side effect are listed under Side Effects.

While you are being given Magnesium Sulfate Heptahydrate 50% Concentrated Injection

Things you must do

If you are about to be started on any new medicine, remind your doctor and pharmacist that you have been given Magnesium Sulfate Heptahydrate 50% Concentrated Injection.

Tell any other doctors, dentists, and pharmacists who treat you that you have been given this medicine.

If you are going to have surgery, tell the surgeon or anaesthetist that you have been given this medicine. It may affect other medicines used during surgery.

If you are about to have any blood tests, tell your doctor that you have been given this medicine. It may interfere with the results of some tests.

If you plan to become pregnant, tell your doctor that you have been given this medicine. Your doctor can discuss with you the risks and benefits involved.

Things to be careful of

Be careful driving or operating machinery until you know how Magnesium Sulfate Heptahydrate 50% Concentrated Injection affects you. This medicine may cause drowsiness, dizziness or light-headedness in some people.

If you feel light-headed, dizzy or faint when getting out of bed or standing up, get up slowly. Standing up slowly, especially when you get up from bed or chairs, will help your body get used to the change in position and blood pressure. If this problem continues, or gets worse, talk to your doctor.

Side Effects

Tell your doctor or nurse as soon as possible if you do not feel well while you are being given Magnesium Sulfate Heptahydrate 50% Concentrated Injection.

Magnesium sulfate heptahydrate helps most people with low levels of magnesium in their bodies, but it may have unwanted side effects in a few people. All medicines can have side effects. Sometimes they are serious, most of the time they are not. You may need medical treatment if you get some of the side effects.

Do not be alarmed by the following list of side effects. You may not experience any of them.

Ask your doctor to answer any questions you may have.

Tell your doctor immediately if you notice any of the following:

  • drowsiness, dizziness or light-headedness
  • nausea and vomiting
  • a feeling of weakness in the muscles or loss of muscle movement
  • breathing difficulties
  • blurred vision or double vision
  • irregular or slow heartbeat
  • chest pain
  • redness of the face and neck.

The above list includes very serious side effects. You may need urgent medical attention or hospitalisation. These side effects are very rare.

Tell your doctor or pharmacist if you notice anything that is making you feel unwell.

Other side effects not listed above may also occur in some people.

Some of these side effects can only be found when your doctor does tests from time to time to check your progress.

After being given Magnesium Sulfate Heptahydrate 50% Concentrated Injection

Storage

Magnesium Sulfate Heptahydrate 50% Concentrated Injection will be stored in the pharmacy, or on the ward of a hospital. The injection is kept in a cool dry place where the temperature stays below 25°C.

Magnesium Sulfate Heptahydrate 50% Concentrated Injection will be opened for use on you. It will be used only once and then it will be discarded. It will never be stored after it is opened or used for more than one person.

Product description

What it looks like

Magnesium Sulfate Heptahydrate 50% Concentrated Injection 50% is a clear, colourless solution in a clear glass vial with a grey rubber stopper and aluminium seal with a blue plastic flip off cap.

Magnesium Sulfate Heptahydrate 50% Concentrated Injection is available in either a 5 mL vial or a 10 mL vial.

The vial stopper is not made with natural rubber latex.

Ingredients

Magnesium Sulfate Heptahydrate 50% Concentrated Injection contains 500 mg/mL magnesium sulfate heptahydrate in water for injections.

Magnesium Sulfate Heptahydrate 50% Concentrated Injection does not contain lactose, sucrose, gluten, tartrazine, alcohol, dyes or any other preservatives.

Manufacturer

Magnesium Sulfate Heptahydrate 50% Concentrated Injection is made in Australia by:

Phebra Pty Ltd
19 Orion Road
Lane Cove West, NSW 2066
Australia

Magnesium Sulfate Heptahydrate 50% Concentrated Injection 5 mL vial
AUST R 23076
Phebra product code INJ056

Magnesium Sulfate Heptahydrate 50% Concentrated Injection 10 mL vial
AUST R 160885
Phebra product code INJ011

This leaflet was updated in Oct 2019.

Published by MIMS December 2019

BRAND INFORMATION

Brand name

Phebra Magnesium Sulfate Heptahydrate 50% Injection

Active ingredient

Magnesium sulfate heptahydrate

Schedule

Unscheduled

 

1 Name of Medicine

Magnesium sulfate heptahydrate.

2 Qualitative and Quantitative Composition

Each mL of injection contains magnesium sulfate heptahydrate 500 mg. This is equivalent to 2 mmol (4 mEq) of magnesium ions and 2 mmol (4 mEq) of sulfate ions in each mL.
For the full list of excipients, see Section 6.1 List of Excipients.

3 Pharmaceutical Form

Magnesium Sulfate Heptahydrate 50% Concentrated Injection is a clear, colourless, slightly viscous, sterile solution. The pH of the solution ranges between 5.5 and 7.0.

4 Clinical Particulars

4.1 Therapeutic Indications

Parenteral administration of Magnesium Sulfate Heptahydrate 50% Concentrated Injection is indicated for:
the treatment of acute hypomagnesaemia;
the prevention of hypomagnesaemia in patients receiving total parenteral nutrition;
the prevention and treatment of life-threatening seizures in the treatment of toxemias of pregnancy (pre-eclampsia and eclampsia);
emergency treatment of some arrhythmias such as Torsade de Pointes and those associated with hypokalemia.

4.2 Dose and Method of Administration

Careful monitoring of plasma magnesium and other electrolyte concentration is essential whenever using this preparation. An intravenous preparation of a calcium salt should always be available in case of toxicity.
Dosage should be reduced in renal impairment.
Magnesium Sulfate Heptahydrate 50% Concentrated Injection is administered intravenously or intramuscularly.

Intravenous dose.

Intravenous doses should be diluted to a concentration of 20% magnesium or less.
Each 5 mL vial of Magnesium Sulfate Heptahydrate 50% Concentrated Injection should be diluted by adding at least 7.5 mL of a compatible solution.
Each 10 mL vial of Magnesium Sulfate Heptahydrate 50% Concentrated Injection should be diluted with at least 15 mL of a compatible solution (see Compatibilities).

Intramuscular dose.

A concentration of less than 25-50% is satisfactory for adults, while a concentration of less than 20% should be used for infants or children. For adult intramuscular administration dilution of Magnesium Sulfate Heptahydrate 50% Concentrated Injection is not required, but each 5 mL vial may be diluted by adding up to 5 mL of a compatible solution and each 10 mL vial with 10 mL of a compatible solution.
The dose of magnesium should be adjusted according to the patient's individual requirements and response.
The total adult daily dose should not exceed 30-40 g of magnesium sulfate per day.

Mild hypomagnesaemia.

Adults.

A dose of 1 g magnesium sulfate intramuscularly every 6 hours for 4 doses is recommended.

Severe hypomagnesaemia.

Adults.

A dose of 0.25 g/kg magnesium sulfate intramuscularly over 4 hours is recommended. Alternatively a dose of 5 g may be given by slow intravenous infusion over 3 hours.

Total parenteral nutrition.

Adults.

A dose of 0.5-3.0 g magnesium sulfate daily may be administered.

Infants.

A dose of 0.25-1.25 g magnesium sulfate daily may be administered.

Torsade de pointes and hypokalemia associated arrhythmias.

Usual dose is 2 g of magnesium sulfate by slow intravenous infusion over 20 minutes.

Toxemia of pregnancy.

An initial intravenous dose of 4 g of magnesium sulfate is suggested. This is followed by an intramuscular dose of 4-5 g into each buttock. This may be followed by a dose of 4-5 g into alternate buttocks every 4 hours as needed.

Compatibilities.

Magnesium Sulfate Heptahydrate 50% Concentrated Injection is reported to be chemically stable and compatible with: sodium chloride 0.9%; lactated Ringer's injection; glucose 5% in water; glucose 5% in sodium chloride 0.9%.
It has been reported that at a concentration of 15 g/L, Magnesium Sulfate Heptahydrate 50% Concentrated Injection is chemically stable and compatible in all the infusion fluids listed above for 24 hours and stored below 25°C. However, in order to reduce microbial contamination, the further diluted solutions should be prepared, stored and used within 24 hours.

4.3 Contraindications

Magnesium Sulfate Heptahydrate 50% Concentrated Injection is contraindicated in patients with:
heart block, since magnesium may exacerbate this condition;
renal failure (creatinine clearance < 20 mL/min), or hepatic disorders since there is an increased risk of hypermagnesaemia in these patients.
Magnesium Sulfate Heptahydrate 50% Concentrated Injection should not be administered to pregnant women in the two hours prior to delivery, unless it is the only therapy available to prevent eclamptic seizures. There is a risk that the neonate will be born with hypermagnesaemia and depressed breathing.

4.4 Special Warnings and Precautions for Use

Magnesium Sulfate Heptahydrate 50% Concentrated Injection may precipitate an acute myasthenic crisis. Sensitivity to parenteral magnesium has been reported. An intravenous preparation of a calcium salt (e.g. calcium gluconate) should be readily available for use when magnesium sulfate is given intravenously.

Use in hepatic impairment.

Magnesium should be administered with caution in patients with impaired hepatic function, since the risk of hypermagnesaemia is increased in these patients.

Use in renal impairment.

Magnesium should be administered with caution in patients with impaired renal function, since the risk of hypermagnesaemia is increased in these patients.

Use in the elderly.

No data available.

Paediatric use.

See Section 4.2 Dose and Method of Administration, Intramuscular dose, Total parenteral nutrition.

Effects on laboratory tests.

Monitoring of serum magnesium levels is advised at periodic intervals during therapy to ensure that normal serum magnesium levels are not exceeded.
The patellar reflex should be tested prior to administering repeat doses of Magnesium Sulfate Heptahydrate 50% Concentrated Injection. Suppression of the reflex is an indication of magnesium intoxication.
Respiration rate should be determined and should be at least 16 per minute prior to each dose of magnesium sulfate, 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.

4.5 Interactions with Other Medicines and Other Forms of Interactions

Magnesium Sulfate Heptahydrate 50% Concentrated Injection can interact with the following drugs:

Cardiac glycosides/ digitalis.

Magnesium salts should be administered with caution in patients treated with cardiac glycosides, since heart block may occur if calcium salts are required to treat magnesium toxicity (see Section 4.9 Overdose).

CNS depressants.

Concurrent use of magnesium salts and CNS depressant drugs may result in an enhanced CNS depressant effect.

Neuromuscular blocking agents.

Concurrent use of magnesium salts with neuromuscular blocking agents such as tubocurarine, suxamethonium and vercuronium may result in an excessive neuromuscular blockade.

Nifedipine.

Concurrent use of magnesium sulfate and nifedipine may result in an exaggerated hypotensive response.

4.6 Fertility, Pregnancy and Lactation

Effects on fertility.

No data available.
(Category D)
Magnesium Sulfate Heptahydrate 50% Concentrated Injection has been administered to pregnant women to treat seizures associated with severe pre-eclampsia and eclampsia. However, increased paediatric mortality has been noted when it was used in pre-term labour.
Magnesium sulfate readily crosses the placenta. Fetal serum concentrations are approximately those of the mother. If magnesium sulfate is administered in the two hours preceding delivery, the neonate may be born with signs of hypermagnesaemia, including respiratory depression, and therefore Magnesium Sulfate Heptahydrate 50% Concentrated Injection should not be given in the two hours preceding delivery unless it is the only therapy available to prevent or treat eclamptic seizures. Fetal heart rate should be monitored.
Bony abnormalities and congenital rickets have been reported in neonates born to mothers treated with parenteral magnesium sulfate for prolonged periods of time (5 to 7 days duration).
Magnesium sulfate should only be used in pregnancy where the benefit outweighs the risk.
 Magnesium Sulfate Heptahydrate 50% Concentrated Injection should not be used during lactation. After intravenous administration, magnesium is distributed into breast milk, and the concentration of magnesium in the breast milk is approximately twice that in the maternal serum. However, magnesium is cleared from the breast milk within 24 hours of the cessation of the infusion.

4.7 Effects on Ability to Drive and Use Machines

The effects of this medicine on a person's ability to drive and use machines were not assessed as part of its registration.

4.8 Adverse Effects (Undesirable Effects)

Excessive administration of magnesium sulfate may result in hypermagnesaemia. The signs of hypermagnesaemia may include drowsiness, loss of deep tendon reflexes, nausea, vomiting, flushing, hypotension, bradycardia, muscle weakness, muscle paralysis, blurred or double vision and CNS depression.
More severe hypermagnesaemia may result in respiratory depression, respiratory paralysis, renal failure, coma, cardiac arrhythmias and cardiac arrest. Hypocalcaemia with tetany, secondary to hypermagnesaemia, has been reported.
After intramuscular injection, irritation and pain at the injection site may result.

Reporting suspected adverse reactions.

Reporting suspected adverse reactions after registration of the medicinal product is important. It allows continued monitoring of the benefit-risk balance of the medicinal product. Healthcare professionals are asked to report any suspected adverse reactions at www.tga.gov.au/reporting-problems.

4.9 Overdose

Hypermagnesaemia may occur when large doses of magnesium are given, especially in patients with renal failure. Signs of hypermagnesaemia include: nausea, vomiting, flushing, hypotension, muscle weakness, muscle paralysis, blurred or double vision, CNS depression and loss of reflexes. More severe hypermagnesaemia may result in respiratory depression, respiratory paralysis, renal failure, coma, cardiac arrhythmias and cardiac arrest.

Treatment of overdosage.

In the treatment of hypermagnesaemia, the following measures may be required.
Blood pressure and respiratory support.
Intravenous administration of 2.5-10 mmol calcium salts (such as calcium gluconate) reverses the effects of magnesium toxicity.
Dialysis may be required, particularly if renal function is impaired.
If renal function is normal, adequate fluids should be given so that urine output is at least 60 mL/hr to assist removal of magnesium from the body.
Physostigmine (0.5-1.0 mg subcutaneously) may be helpful, but routine use is not recommended due to the potential toxicity.
For information on the management of overdose, contact the Poisons Information Centre on 131126 (Australia).

5 Pharmacological Properties

5.1 Pharmacodynamic Properties

Mechanism of action.

Magnesium is an essential body cation and the second most abundant cation of intracellular fluid. It is an essential cation in numerous enzymatic processes, and is necessary for several steps in glycolysis, the Krebs cycle and in protein and nucleic acid synthesis. It is thus vital for normal energy storage and transfer, skeletal development, nerve conduction and muscle contraction. Magnesium plays an important role in neurochemical transmission, and is essential for proper neurochemical functioning.
Magnesium has an anticonvulsant effect. It possibly has antiarrhythmic effects and a role in calcium homeostasis and bone mineralisation. There is conflicting evidence that the routine use of intravenous magnesium sulfate in the setting of acute myocardial infarction is beneficial.
Deficiency of magnesium is closely associated with other electrolyte disturbances, particularly hypocalcaemia and hypokalemia. The specific symptoms of hypomagnesaemia are therefore difficult to determine, but may include nausea, vomiting, muscle weakness, neuromuscular dysfunction such as paraesthesia, tremor and cramp, tachycardia and cardiac arrythmias.

Clinical trials.

No data available.

5.2 Pharmacokinetic Properties

The 95% confidence intervals for magnesium levels in healthy Australian subjects are: neonate 0.6-0.9 mmol/L and adult 0.8-1.0 mmol/L.

Distribution.

Approximately 50% of magnesium in the body is found in bone, with the majority of the remainder stored in muscle and soft tissue. 1% or less is contained in the extracellular compartment, of which approximately 33% is protein-bound, with a further 12% bound to anions.

Metabolism.

No data available.

Excretion.

Magnesium is primarily excreted in the urine, with small amounts excreted in faeces, saliva and breast milk. Over 90% of magnesium filtered by the kidneys is reabsorbed, mainly in the ascending limb of the Loop of Henle, with significant amounts also absorbed in the proximal and distal tubules. The clearance is proportional to the plasma magnesium concentration and the glomerular filtration rate.
The onset of action after intramuscular injection is about 1 hour and after intravenous injection is nearly immediate. The duration of action after intramuscular injection is 3 to 4 hours, and after intravenous injection is about 30 minutes.

5.3 Preclinical Safety Data

Genotoxicity.

No data available.

Carcinogenicity.

No data available.

6 Pharmaceutical Particulars

6.1 List of Excipients

Water for injections.

6.2 Incompatibilities

Magnesium sulfate is incompatible with calcium salts. Calcium sulfate may precipitate when calcium salts are mixed with magnesium sulfate in the same intravenous solution.
Magnesium salts have also been reported to be incompatible with alkali carbonates and bicarbonates and soluble phosphates.

6.3 Shelf Life

In Australia, information on the shelf life can be found on the public summary of the Australian Register of Therapeutic Goods (ARTG)1. The expiry date can be found on the packaging.
1AUST R 23076 (2.5 g/5 mL); AUST R 160885 (5 g/10 mL).

6.4 Special Precautions for Storage

Store below 25°C.

6.5 Nature and Contents of Container

Magnesium Sulfate Heptahydrate 50% Concentrated Injection is presented as: 5 mL vial as a pack of 10 vials. Phebra product code- INJ056.
10 mL vial as a pack of 10 vials. Phebra product code- INJ011.
The vial stopper is not made with natural rubber latex.

6.6 Special Precautions for Disposal

In Australia, any unused medicine or waste material should be disposed of in accordance with local requirements.

6.7 Physicochemical Properties

The molecular weight of the compound is 246.5. The molecular formula is MgSO4.7H2O.

CAS number.

10034-99-8.

7 Medicine Schedule (Poisons Standard)

Unscheduled.

Summary Table of Changes