Magnesium Infusions: What an IV Magnesium Drip Does, Who It Suits and What to Expect

"Magnesium infusion" is searched far more often than "magnesium drip", and the searches cover two very different things: the magnesium sulphate drip given in hospital for emergencies, and the wellness drip offered by private clinics. This guide covers both, because it matters which one you are reading about. It explains what magnesium does, who tends to run low, why a blood test and tablets are the sensible first steps, what our Calm Drip contains and costs, who it is not for, and what to expect on the day.

What magnesium does

Magnesium is a mineral involved in several hundred enzyme reactions. The authorised health claims, the ones regulators accept as proven, are that magnesium contributes to normal muscle function, the normal functioning of the nervous system, normal psychological function, normal energy metabolism, the maintenance of normal bones and teeth, and the reduction of tiredness and fatigue. It also relaxes smooth muscle, including the muscle in the walls of blood vessels, which is why it has a place in hospital medicine and why we check your blood pressure around a magnesium drip.

Most of the body's magnesium is in bone and inside cells. Only around 1% is in the blood, which has a practical consequence for testing that we come to below.

Who runs low

A varied diet with green vegetables, nuts, seeds, wholegrains and pulses supplies enough magnesium for most people. Low levels are more likely if:

• You take a proton pump inhibitor such as omeprazole or lansoprazole long term. This is a recognised cause and is the one most often missed.
• You take a diuretic (water tablet), particularly a loop diuretic such as furosemide.
• You drink alcohol heavily. Alcohol increases magnesium loss through the kidneys.
• You have diabetes, especially if it is not well controlled.
• You have a bowel condition that affects absorption, such as coeliac disease, Crohn's disease or a short bowel, or you have chronic diarrhoea.
• You sweat heavily and often, for example endurance athletes training in heat.
• You are older, eat poorly, or take certain chemotherapy or immune-suppressing medicines.

The symptoms of low magnesium are vague and overlap with many other things: muscle cramps and twitching, tiredness, palpitations, poor sleep, low mood. None of them is specific, which is exactly why it is worth measuring rather than guessing. Our guide to the signs of magnesium deficiency goes through them in more detail.

Test first, tablets second, infusion third

This is the order a GP would recommend, and it is the order we recommend even though we sell the drip.

Test first. A serum magnesium test is £35 and tells you whether the level in your blood is low. Because only a small fraction of magnesium is in the blood, a normal serum result does not completely exclude a low total body store; a red cell magnesium test (£65) measures the magnesium inside red blood cells and is a better guide to tissue levels. If you have a reason to suspect deficiency, test before you treat.

Tablets second. For most people with a low or borderline result, oral magnesium for a few weeks corrects it. Magnesium citrate and glycinate are generally better absorbed and gentler on the bowel than magnesium oxide. The common side effect is loose stools, which is dose-related.

Infusion third. An intravenous dose is reasonable when tablets are not tolerated, when absorption from the gut is the problem, or when someone has had their level checked, understands what the drip does, and wants it. It is not a first-line treatment for tiredness, and we will say so if that is why you have come.

What is in our Calm Drip

The Calm Drip is the Myers cocktail with an extra 1 gram of magnesium in the bag. The Myers cocktail itself contains B vitamins, vitamin C, magnesium, calcium, zinc and selenium in 1 litre of fluid, so the Calm Drip is the full multivitamin drip with the magnesium dose raised. It runs over about 45 minutes from start to finish and costs £199.

Glutathione, vitamin B12, vitamin B complex and vitamin D injections can be added after the bag. Add-ons are given separately once the drip has finished and are never mixed into it. The B vitamins in the bag and the vitamin B12 as an add-on both contribute to normal energy metabolism and the reduction of tiredness and fatigue.

What happens at the appointment

Eat something and drink water before you come; do not arrive fasting. Bring a list of your medications and any supplements. Every drip starts with a short consultation with the doctor, who goes through the safety list below and checks your pulse and blood pressure. For a magnesium drip that blood pressure check matters more than usual, because magnesium relaxes blood vessels and can lower blood pressure a little during and after the drip. If your blood pressure is already low, the doctor may decide against it or run it more slowly.

A small cannula is placed in a vein in your arm and the bag runs over about 45 minutes. A warm feeling or a flush is expected with magnesium, more so than with the other drips, and a metallic taste can happen. Both pass. You sit comfortably with a drink. Your pulse and blood pressure are checked again before you leave, and you can drive home afterwards.

Who should not have it

Please tell us before your appointment if any of these apply, so we can advise you or rebook without charge:

• You have kidney disease. The kidneys clear magnesium, and intravenous magnesium can accumulate to dangerous levels if they are not working properly. This is the most important exclusion for a magnesium drip.
• You have heart block, a very slow pulse, or heart failure. Magnesium slows conduction in the heart.
• You have myasthenia gravis. Magnesium can worsen muscle weakness in this condition.
• You are pregnant or breastfeeding.
• You have a liver condition.
• You are under 18 or over 60.
• You have a known allergy to any vitamin or mineral.
• You have a haemolytic condition such as G6PD deficiency, sickle cell, spherocytosis or thalassaemia.

Tell us about every medication you take. Magnesium interacts with some antibiotics, bisphosphonates for bone thinning, and medicines that slow the heart, and the doctor needs the full list.

Side effects and what to watch for

The flush and warmth during the drip are the commonest effects and are expected. A small fall in blood pressure can cause light-headedness, which is why you are checked before you leave. Mild tiredness or a headache for a day afterwards can happen, and a little bruising at the cannula site. Because the magnesium is cleared by the kidneys you may pass more urine for a few hours.

Contact us if the cannula site becomes hot, swollen or painful in the days afterwards, or if you develop a fever or a rash. If you have severe difficulty breathing or swelling of the face or lips, call 999. Symptoms of too much magnesium are unlikely at this dose in someone with normal kidneys, but marked drowsiness, muscle weakness or a very slow pulse after the drip should be reported urgently.

Where we are

OneMedicine is a CQC-registered clinic at 1 High Street, Kings Heath, Birmingham B14 7AR, opposite Kings Heath railway station, with free parking at the rear of the clinic. Drips are given by Dr Ahmed in the Infusions and Vitamins Room and everything is booked online, with no referral needed.

Frequently asked questions

What does a magnesium infusion do?

It raises blood magnesium directly, bypassing the gut. Magnesium contributes to normal muscle and nerve function, normal psychological function and the reduction of tiredness and fatigue. In someone whose level is genuinely low it corrects the deficiency faster than tablets; in someone whose level is normal, the benefit is not established.

How long does a magnesium drip take?

Our Calm Drip runs over about 45 minutes from start to finish, including the consultation and the blood pressure checks before and after. Add-ons given after the bag add a few minutes.

Is a magnesium infusion the same as the magnesium sulphate drip in hospital?

No. The hospital drip is a high dose of magnesium sulphate given rapidly, under monitoring, for emergencies such as eclampsia, severe asthma and certain arrhythmias. A clinic magnesium drip is a much lower dose in a multivitamin bag given slowly to a well person.

What are the side effects of a magnesium infusion?

A warm flush during the drip, a possible small fall in blood pressure with light-headedness, and mild tiredness or a headache for a day. Serious effects are rare at this dose in people with normal kidneys, which is why kidney disease is the main exclusion.

Should I have a blood test before a magnesium drip?

We think so, if your reason for wanting it is a suspected deficiency. A serum magnesium test is £35 and a red cell magnesium test is £65. A low result justifies treatment and makes tablets a sensible first step; a normal result is worth knowing before you spend £199.

How much does a magnesium drip cost?

The Calm Drip is £199 at OneMedicine, including the GP consultation and blood pressure checks. Add-ons after the bag cost from £20.

Can I have a magnesium drip if I have kidney problems?

No. Magnesium is cleared by the kidneys and can build up to harmful levels if they are not working well. Tell us about any kidney condition before you book.

Is there a magnesium infusion near me in Birmingham?

Yes. OneMedicine is in Kings Heath, south Birmingham, opposite the railway station with free parking at the rear, and appointments are booked online.

Written by Dr Ibrar Ahmed — MBChB MRCP MRCGP PhD PG Dip (Cardiology)
Specialist interest: Cardiovascular Medicine · OneMedicine, CQC-registered clinic