Consumer medicine information

DBL Magnesium Sulfate Concentrated Injection

Magnesium sulfate heptahydrate

BRAND INFORMATION

Brand name

DBL Magnesium Sulfate Concentrated Injection

Active ingredient

Magnesium sulfate heptahydrate

Schedule

Unscheduled

What is in this leaflet

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

All medicines have risks and benefits. Your doctor has weighed the risks of you being given magnesium sulfate heptahydrate against the benefits they expect it will have for you.

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

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

What DBL Magnesium Sulfate Concentrated Injection is used for

This medicine is used to:

treat very low levels of magnesium in the body
prevent low levels of magnesium in patients receiving total parenteral nutrition
prevent and treat seizures (fits) in pregnant women due to pre-eclampsia or eclampsia (also called toxaemia of pregnancy).

This medicine 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 it for another reason.

This medicine is not addictive.

Before you are given DBL Magnesium Sulfate Concentrated Injection

When you must not be given it

You must not be given DBL Magnesium Sulfate Concentrated Injection if you have an allergy to:

any medicine containing magnesium.

Some of the 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 must not be given this medicine if you have:

heart block (a slow or irregular heart beat)
severe kidney disease.

This medicine must not be given to pregnant women in the 2 hours prior to delivery, unless it is the only therapy available to prevent or treat eclamptic seizures.

Use of this medicine in pregnancy for prolonged periods of time (5-7 days duration) should be avoided unless indicated by your doctor.

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.

Tell your doctor if you are breast-feeding. 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.

Taking other medicines

Tell your doctor or pharmacist if you are taking any other medicines, including any that you get without a prescription from your pharmacy, supermarket or health food shop.

Some medicines and magnesium sulfate heptahydrate may interfere with each other. These include:

digoxin, a medicine used to treat heart failure
central nervous system depressants (medicines that cause drowsiness or sedation)
neuromuscular blocking agents (medicines used to relax muscles during surgery)
nifedipine, a medicine used to treat high blood pressure or angina.

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

Your doctor and pharmacist may have more information on medicines to be careful; with or avoid while being given this medicine.

How DBL Magnesium sulfate concentrated injection is given

How much is given

Your doctor will decide what dose of magnesium sulfate heptahydrate you will receive and how long you will receive it for. This depends on your medical condition and other factors, such as your weight.

How it is given

DBL Magnesium Sulfate Concentrated Injection may be given as an injection into the vein (intravenous) or into the muscle (intramuscular).

This medicine must only be given by a doctor or nurse.

If you take too much (overdose)

As DBL Magnesium Sulfate Concentrated Injection is given to you under the supervision of your doctor, it is very unlikely that you will receive too much.

Immediately telephone your doctor or the Poisons Information Centre on 13 11 26 for advice, or go to Accident and Emergency at the nearest hospital, if you think that you or anyone else may have taken too much DBL Magnesium Sulfate Concentrated Injection. Do this even if there are no signs of discomfort or poisoning. You may need urgent medical attention.

Symptoms of a magnesium sulfate heptahydrate overdose may include the side effects listed below in the ‘Side effects’ section, but are usually of a more severe nature.

While you are being given DBL Magnesium Sulfate Concentrated Injection

Things you must do

If you are about to be started on any new medicine, remind your doctor and pharmacist that you are receiving magnesium sulfate heptahydrate.

Tell any other doctors, dentists, and pharmacists who treat you that you are taking this medicine.

If you become pregnant while taking this medicine, tell your doctor immediately.

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

Keep all of your doctor’s appointments so that your progress can be checked. Your doctor may do some tests from time to time to make sure the medicine is working and to prevent unwanted side effects.

Things you must do

Be careful driving or operating machinery until you know how magnesium sulfate heptahydrate affects you. This medicine may cause blurred or double vision in some people. If you have any of these symptoms, do not drive, operate machinery or do anything else that could be dangerous.

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. Magnesium sulfate heptahydrate helps most people with low magnesium levels, or in toxaemia of pregnancy, but 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 attention if you get some of the side effects.

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

Ask your doctor or pharmacist to answer any questions you may have.

Tell your doctor or nurse if you notice any of the following and they worry you:

pain or irritation at the injection site (usually following intramuscular injection).

This side effect is usually mild and short-lived.

Tell your doctor or nurse as soon as possible if you notice any of the following:

nausea or vomiting
flushing
dizziness or fainting (due to low blood pressure)
drowsiness or sedation
muscle weakness
blurred or double vision.
sweating

The above list includes serious side effects which may require medical attention. Serious side effects are rare.

If any of the following happen, tell your doctor or nurse immediately:

muscle paralysis
difficulty breathing
changes in heart rate
passing little or no urine.

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 nurse if you notice anything that is making you feel unwell. Other side effects not listed above may also occur in some people.

After being given DBL™ Magnesium Sulfate Concentrated Injection

Storage

DBL Magnesium Sulfate Concentrated Injection will be stored in the pharmacy or on the ward. The injection is kept in a cool dry place, protected from light, where the temperature stays below 25C.

Product description

What it looks like

DBL Magnesium Sulfate Concentrated Injection is a clear, colourless solution packaged in glass ampoules.

Ingredients

Each ampoule of DBL Magnesium Sulfate Concentrated Injection contains

magnesium sulfate heptahydrate as the active ingredient.

Each ampoule also contains:

water for injection.

Sponsor

DBL Magnesium Sulfate Concentrated Injection is supplied by:

Australian Sponsor:

Pfizer Australia Pty Ltd
Sydney NSW
Toll Free Number: 1800 675 229
www.pfizer.com.au

DBL Magnesium Sulfate Concentrated Injection is supplied in the following strength:

2.465 grams in 5mL ampoule AUST R 16311

This leaflet was updated in September 2021.

Published by MIMS October 2021

BRAND INFORMATION

Brand name

DBL Magnesium Sulfate Concentrated Injection

Active ingredient

Magnesium sulfate heptahydrate

Schedule

Unscheduled

1 Name of Medicine

Magnesium sulfate heptahydrate.

2 Qualitative and Quantitative Composition

Each ampoule contains 2.465 g magnesium sulfate heptahydrate (493 mg/mL). Each mL of injection contains 2 mmol (4 mEq) of magnesium ions and 2 mmol (4 mEq) of sulfate ions.
For the full list of excipients, see Section 6.1 List of Excipients.

3 Pharmaceutical Form

DBL Magnesium Sulfate Concentrated Injection is a clear, colourless, 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 is indicated in the treatment of acute hypomagnesaemia.
Magnesium salts are also indicated to prevent hypomagnesaemia in patients receiving total parenteral nutrition.
Magnesium sulfate heptahydrate is also indicated in the prevention and treatment of life threatening seizures in the treatment of toxemias of pregnancy (pre-eclampsia and eclampsia).

4.2 Dose and Method of Administration

Magnesium sulfate heptahydrate is administered intravenously or intramuscularly.
Intravenous doses should be diluted to a concentration of 20% magnesium or less. For intravenous dosing, each 5 mL ampoule of DBL Magnesium Sulfate Concentrated Injection should be diluted by adding at least 7.5 mL of a compatible solution (see Section 4.2 Dose and Method of Administration, Compatibilities).
For intramuscular dosing, a concentration of 25 to 50% is satisfactory for adults, while a concentration of 20% should be used for infants or children. For adult intramuscular administration dilution of DBL Magnesium Sulfate Concentrated Injection is not required, but each 5 mL ampoule could be diluted by adding up to 5 mL of a compatible solution.
The dose of magnesium should be adjusted according to the patients individual requirements and response.
The total adult daily dose should not exceed 30 to 40 g of magnesium sulfate heptahydrate per day.

Mild hypomagnesaemia.

Adults.

A dose of 1 g magnesium sulfate heptahydrate (8 mEq) intramuscularly every 6 hours for 4 doses is recommended.

Severe hypomagnesaemia.

Adults.

A dose of 0.25 g/kg magnesium sulfate heptahydrate 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 to 3.0 g magnesium sulfate heptahydrate (4 to 24 mEq) daily may be administered.

Infants.

A dose of 0.25 to 1.25 g magnesium sulfate heptahydrate (2 to 10 mEq) daily may be administered.

Toxemia of pregnancy.

An initial intravenous dose of 4 g magnesium sulfate heptahydrate is recommended. This is followed by an intramuscular dose of 4 to 5 g into each buttock. This may be followed by a dose of 4 to 5 g into alternate buttocks every four hours as needed.
Alternatively, the initial IV dose may be followed by an infusion of 1 to 2 g/hr.

Compatibilities.

Magnesium sulfate heptahydrate is reported to be chemically stable and compatible with either sodium chloride 0.9%, lactated Ringer's injection, glucose 5% in water, or glucose 5% in sodium chloride 0.9%. It has been reported that at a concentration of 15 g/L, magnesium sulfate heptahydrate 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 is contraindicated in patients with heart block, since magnesium may exacerbate this condition.
Magnesium is also contraindicated in patients with renal failure (creatinine clearance < 20 mL/min), since there is an increased risk of hypermagnesaemia in these patients.
Magnesium sulfate heptahydrate 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 may precipitate an acute myasthenic crisis. Sensitivity to parenteral magnesium has been reported.
Monitoring serum magnesium levels and the patient's clinical status is essential to avoid the consequences of overdosage in toxemia.
An intravenous preparation of a calcium salt (e.g. calcium gluconate) should be readily available for use when magnesium sulfate heptahydrate is given intravenously.

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.

No data available.

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. 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 heptahydrate, 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

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 may result in an excessive neuromuscular blockade.

Nifedipine.

Concurrent use of magnesium sulfate heptahydrate and nifedipine may result in an exaggerated hypotensive response.
Drug induced renal losses of magnesium occur with the following drugs and drug classes:
Aminoglycosides, ciclosporin, amphotericin B, diuretics, cisplatin.
Also see Section 6.2 Incompatibilities.

4.6 Fertility, Pregnancy and Lactation

Effects on fertility.

No data available.
Magnesium sulfate heptahydrate is administered to pregnant women to treat seizures associated with severe pre-eclampsia and eclampsia. Magnesium sulfate heptahydrate readily crosses the placenta. Foetal serum concentrations approximate those of the mother. If magnesium sulfate heptahydrate is administered in the two hours preceding delivery, the neonate may be born with signs of hypermagnesaemia, including respiratory depression, and therefore DBL Magnesium Sulfate 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.
Bony abnormalities and congenital rickets have been reported in neonates born to mothers treated with parenteral magnesium sulfate heptahydrate for prolonged periods of time (5-7 days duration).
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. Magnesium salts should therefore be used with caution in lactating patients. 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 heptahydrate may result in hypermagnesaemia. The signs of hypermagnesaemia may include: nausea, vomiting, flushing, hypotension, sweating, hypothermia, circulatory collapse, 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. Hypocalcaemia with tetany, secondary to hypermagnesaemia, has been reported.
After intramuscular injection, irritation and pain at the injection site may result.

Reporting suspected adverse effects.

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 http://www.tga.gov.au/reporting-problems.

4.9 Overdose

Clinical features.

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.
Disappearance of the patellar reflex is a useful clinical sign to detect the onset of magnesium intoxication.

Treatment.

In the treatment of hypermagnesaemia, the following measures may be required:
blood pressure and respiratory support;
intravenous administration of 2.5 to 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 to 1.0 mg subcutaneously) may be helpful, but routine use is not recommended due to the potential toxicity.
Hypermagnesemia in the newborn may require resuscitation and assisted ventilation as well as IV calcium.
For information on the management of overdose, contact the Poisons Information Centre on 13 11 26 (Australia).

5 Pharmacological Properties

5.1 Pharmacodynamic Properties

Mechanism of action.

Magnesium is the second most abundant cation of intracellular fluid. It is an essential cation in over 300 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. 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 heptahydrate in the setting of acute myocardial infarction is beneficial.
Deficiency of magnesium is closely associated with other electrolyte disturbances, particularly hypocalcaemia and hypokalaemia. 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 to 0.9 mmol/L and adult 0.8 to 1.0 mmol/L.
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.
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.
Also see Section 4.5 Interactions with Other Medicines and Other Forms of Interactions.

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). The expiry date can be found on the packaging.

6.4 Special Precautions for Storage

Store below 25°C.

6.5 Nature and Contents of Container

DBL Magnesium Sulfate Concentrated Injection is supplied in glass ampoules.

Strength.

Magnesium sulfate heptahydrate 49.3%.

Pack.

10 x 5 mL ampoules.

6.6 Special Precautions for Disposal

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

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