Magnesium Deficiency in Dogs

Dogs require essential vitamins and minerals just like humans do. One of these key nutrients is magnesium, involved with energy production at the cellular level. Every time your pet moves a muscle, experiences a heartbeat, or has a thought, magnesium is needed to facilitate that transfer of energy. Also involved are three other minerals: sodium, potassium, and calcium, all dependent to some degree on the action of magnesium. These minerals are necessary for proper heart function, muscle movement and nervous system signaling. Sometimes, whether due to malnutrition, diabetes, or kidney damage, an insufficient amount of magnesium is present for use in the body, leading the other three minerals to drop. This can cause weakness, muscle tremors, and heart arrhythmias that can be fatal. Schedule an appointment with the veterinarian immediately if your dog is behaving strangely and is experiencing pain or difficulty walking.

• Muscle weakness or trembling
• Hyperactive or improperly triggered reflexes
• Difficulty walking
• Muscle pain
• Heart arrhythmia
• Lethargy or abnormal behavior

• Malnutrition
• Diabetes
• Kidney damage
• Treatment with diuretics
• Disease inhibiting absorption of nutrients

See the veterinarian immediately if your dog appears weak, has trouble walking or is seeming uncoordinated as these may be signs of magnesium deficiency. This deficiency should be corrected swiftly to avoid fatal heart problems. Tell the veterinarian about any changes to your dog’s diet, any other treatment your dog has received, and whether your dog’s habits have changed with regard to urination and defecation. Sometimes, if your dog has been treated with diuretics (drugs that help to evacuate excess fluid), it may lose too much magnesium in the process of urinating out all this fluid.

The veterinarian will listen to your dog’s heart, and if any abnormality is detected, will likely order an ECG. An ECG is a medical device which displays the patterns of your dog’s heartbeat on a screen using terminals taped to your dog’s chest. This is a simple machine and most veterinarians will have one. The classic signs of low magnesium are prolonged PR intervals, widened QRS complexes, depressed ST segments and peaked T-waves.

For the next step, even if your dog does not exhibit these cardiac symptoms, the vet will likely order a blood electrolyte test, which will measure the amounts of minerals like magnesium, potassium, calcium and sodium in your pet’s blood, in addition to some other common electrolytes. This gives a definitive picture of what is and is not making its way into your pet’s bloodstream. This test will need to be sent to the lab and may take a short while to perform. If these come back with low magnesium your vet will discuss treatment options.

A number of conditions can lead to low magnesium, such as diabetes, kidney damage or treatment with drugs that stress the kidneys, and diseases that hinder nutrient absorption like IBD. If these are well-controlled, it is unlikely a magnesium deficit will appear. If it does, this could indicate the pre-existing condition needs further treatment.

Treatment for magnesium deficiency alone is simple- giving the animal chewable or (in more severe cases) IV magnesium supplements is usually all that is needed to correct the condition. In cases such as malnutrition where the deficiency has persisted for some time, correction of the associated electrolytes may be needed as well, particularly potassium and calcium.

Dogs without underlying conditions that are treated swiftly usually make a full recovery. However, their recovery must be supervised carefully especially if magnesium supplements are prescribed. Too much magnesium in the body is also an undesirable condition, and so careful adherence to your veterinarian’s instructions will be essential. Especially in the first few days of treatment, your vet may request daily electrolyte testing and potentially an ECG during administration of the treatment, if given by IV. Do not hesitate to call your vet if any of the symptoms return, or your dog develops any new ones.