By Rania Gollakner, BS, DVM, MPH

What is hawthorn?

Hawthorn is a supplement derived from the Crataegus plants of the rose family and is used to enhance digestion, lower blood cholesterol, and to support the heart. The likely active ingredient in hawthorn is an antioxidant bioflavonoid which is known for improving blood circulation to the heart. In animals, it has been used to manage certain heart diseases such as heart failure.

"The likely active ingredient in hawthorn is an antioxidant bioflavonoid which is known for improving blood circulation to the heart."

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 hawthorn?

Limited studies in animals have been performed, but there is anecdotal evidence that hawthorn works to treat heart and circulation issues. In humans, there are more clinical studies that show the following benefits: improved exercise tolerance, improved low blood pressure, reduced mild high blood pressure, improved parameters for heart failure patients, and reduced sensations of anxiety. There is also some evidence that hawthorn may help with digestive issues such as colitis, high blood sugar, obesity, and high blood triglycerides.

How is hawthorn given?

Hawthorn is given by mouth in the form of a capsule, tablet, liquid extract, or dried berries/leaves. It can be given with or without food; however, if stomach upset occurs when dosed on an empty stomach, give future doses with food. Measure liquid forms carefully. Hawthorn should be given for 6-8 weeks before assessing its 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?

Studies are limited for this supplement and therefore information regarding side effects is also limited. Side effects are uncommon but may include dizziness and stomach upset. Skin rashes are also possible in cases of an allergic reaction.

Are there any risk factors for this supplement?

Studies are limited for this supplement and therefore information regarding risk factors is also limited. Hawthorn should not be used in pets that are allergic to it. Do not use hawthorn in pets that are pregnant or nursing, or in pets with severe liver or kidney disease as safety has not been established in these cases. Hawthorn should be used cautiously in pets that have low blood pressure or low heart rates. In cats with hypertrophic cardiomyopathy, hawthorn should be cautiously, as there is conflicting evidence if it is helpful in these cases.

Are there any drug interactions I should be aware of?

The following medications should be used with caution when given with hawthorn: adenosine, anticoagulants, barbiturates, blood pressure medications, caffeine, cardiac glycosides, epinephrine, papaverine, sodium nitrate, or theophylline.

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 monitor your pet to be sure that the medication is working.

How do I store hawthorn?

In general, store this supplement in a cool, dry place, protected from light. There are many formulations and manufacturers of hawthorn, so always follow the specific storage instructions on the product label.

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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