By Rania Gollakner, BS, DVM, MPH

What is carnitine?

Carnitine (brand names: Carnitor®, Xyzal®), also known as levocarnitine or L-carnitine is an amino acid nutrient used in conjunction with other medications to treat dilated cardiomyopathy (DCM), a type of heart disease in dogs. It has also been used for other heart diseases and for valproic acid toxicity.

In cats, it has been used to aid in the treatment of hepatic lipidosis (fatty liver), but this use is controversial.

Dietary supplements are substances that can be used to supplement the diet, such as vitamins, minerals, amino acids, herbs, botanicals, enzymes, and probiotics. While many supplements are sold over the counter, they still contain ingredients that have biological effects that should be managed by your veterinarian. Follow your veterinarian’s directions and cautions very carefully as their directions may be significantly different from those on the label.

There are differences in how countries regulate supplements. In the United States, these substances are not as vigorously regulated by the FDA as other medications, which means they can be sold without the manufacturer proving their effectiveness, safety, and without a guarantee of consistent or accurately reported ingredients. In Canada, products that have been evaluated for quality, safety, and effectiveness by Health Canada and authorized for sale will have a license number on the label.

How effective is carnitine?

Carnitine supplementation is effective in cases of carnitine deficiency. In other cases, studies have shown mixed but overall promising results that carnitine may be helpful as an adjunctive therapy for treating heart disease.

How is carnitine given?

Carnitine is given by mouth in the form of a capsule, tablet, liquid, or powder. It can be given with or without food; however, if stomach upset occurs when dosed on an empty stomach, give future doses with food. Mix the powder form into food. Measure liquid forms carefully.

This medication can take a few weeks before full effects are noted, but gradual improvements are usually noticeable after a few days; however, effects may not be visibly obvious and therefore laboratory tests may need to be done to evaluate this medication’s effectiveness.

What if I miss giving my pet the supplement?

If you miss a dose, give it when you remember, but if it is close to the time for the next dose, skip the dose you missed and give it at the next scheduled time, and return to the regular dosing schedule. Never give your pet two doses at once or give extra doses.

Are there any potential side effects?

Side effects are rare; the most common side effect is gastrointestinal upset such as mild diarrhea, nausea, or vomiting, and most often occurs with high doses.

This short-acting medication should stop working within 24 hours, although effects can be longer in pets with liver or kidney disease.

Are there any risk factors for this supplement?

Studies are limited for this supplement and therefore information regarding risk factors is also limited.

Do not use the D form of carnitine, especially in combination with the L form; use the L (Levo-) form only.

Use during pregnancy is likely safe, but use cautiously as studies are limited.

Are there any drug interactions I should be aware of?

The following medications should be used with caution when given with carnitine: valproic acid.

Vitamins, herbal therapies, and supplements have the potential to interact with each other, as well as with prescription and over the counter medications. It is important to tell your veterinarian about any medications (including all vitamins, supplements, or herbal therapies) that your pet is taking.

Is there any monitoring that needs to be done with this supplement?

There is no specific monitoring that needs to be done while your pet is taking this medication; your veterinarian may check bloodwork occasionally as this is done in human medicine. Your veterinarian may also monitor your pet to be sure that the medication is working.

How do I store carnitine?

Store this supplement at room temperature in a tight container and protected from light.

What should I do in case of emergency?

If you suspect an overdose or an adverse reaction to the medication, call your veterinary office immediately. If they are not available, follow their directions in contacting an emergency facility.

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