St. John's Wort

St. John's WortWhat is St. John’s Wort?

St. John’s Wort is a herb, prepared from the plant Hypericum perforatum, that is mainly used for treating depression and anxiety disorders in people. This is a fairly modern use of St. John’s Wort. Traditionally, the herb was used to ease the pain of peripheral nerve injuries.

Why recommend administration of St. John’s Wort to my pet?

While St. John’s Wort is typically thought of as promoting human mental health, research indicates that the herb is also anxiolytic (reduces anxiety) in some animal species. In addition, the herb is effective in laboratory animals at reducing depression and psychological stress. Because of these relaxant effects, some practitioners prescribe St. John’s Wort for obsessive compulsive disorders as well as mild anxiety associated with thunderstorms, visits to the groomer or vet’s, and other mild fears and phobias.

Science has also discovered a chemical basis for the herb’s ability to relieve pain, namely a mechanism similar to opiates, which are in the same chemical class as morphine. Hypericum finds use as an analgesic in the management of intervertebral disc disease, tail injuries and following amputation of limbs. Topical application of the essential oil prepared from St. John's Wort may help with mild contusions, muscle aches, and minor skin irritations.

An effect of Hypericum unrelated to the nervous system is its activity against lentiviruses, including FIV (Feline Immunodeficiency Virus) and perhaps even Feline Leukemia. Clinical experience with Hypericum in the management of feline leukemia suggests it is effective, and has a role in the integrated management of this condition.

How much experience is there with the use of St. John’s Wort in pets?

Despite the therapeutic possibilities discussed above, experience with St. John’s Wort in pets is still limited. Veterinarians who have used it by itself or in herbal preparations report positive results. It is a leading prescription remedy for depression in people in Europe.

What species of animals are being treated regularly with St. John’s Wort?

Dogs and cats are treated with St. John’s Wort.

How much research has been conducted on this supplement?

While a significant amount of research has been conducted on the effects of St. John’s Wort in people and laboratory animals, research in pet animals is lacking.

How can my pet benefit from St. John’s Wort?

Pets with mild anxiety, phobic conditions, obsessive compulsive disorders, or depression may benefit. Feline hyperesthesia syndrome, a convulsive disorder of cats, appears amenable to serotonin reuptake inhibitors, and may benefit from the serotonin-raising effects of St. John’s Wort. Feline hyperesthesia can also be considered a severe form of peripheral neuralgia, which was a traditional indication for St. John’s Wort. Psychogenic alopecia (hair loss resulting from psychological reasons) and even acral lick dermatitis (also called lick granuloma) might similarly benefit, given the herb’s relaxant and peripheral analgesic (pain relieving) effects.

Hypericum may also be used to relieve the acute back pain secondary to disc prolapse, phantom pain following amputation of a limb, and tail injuries. Hypericum appears to be effective in the treatment of feline immune deficiency viruses, although these benefits are probably only seen with the use of liquid extracts.

St John's Wort is a pain relieverHow safe is St. John’s Wort?

St. John’s Wort appears quite safe for use in dogs and cats if given under veterinary supervision. Photosensitization (sensitivity to sunlight) is possible with extended use of high doses. Animal and human research has indicated that photosensitization is not likely to occur at the dosages typically used.

St. John's Wort may potentiate (increase the effects of) anesthetics and other sedatives. It is typically recommended for humans that St. John’s Wort not be combined with prescription antidepressants since it has been speculated that the herb acts, like many pharmaceuticals, to increase serotonin levels in the brain. Recent neurophysiological research suggests, however, that St. John’s Wort may act at least partly through other mechanisms. Preliminary investigation suggests that the hypericin in St. John’s Wort may increase the activity of a liver enzyme called cytochrome P-450. Because this enzyme can break down drugs, St. John’s Wort may cause the body to speed the breakdown of various drugs (such as theophylline, an asthma medication), thereby decreasing their effectiveness. St. John's Wort may raise blood pressure, and cause agitation, drowsiness, and confusion in surgical patients.

Finally, preliminary reports from the University of Colorado suggest that St. John’s Wort may interfere with the action of the anti-tumour drugs etoposide (VePesid), teniposide (Vumon), mitoxantrone (Novantrone), and doxorubicin (Adriamycin). More research is needed in these areas.

Safety in young children, pregnant or nursing women, or those with severe liver or kidney disease has not been established. Similar precautions in pets are warranted.

Where do I obtain St. John’s Wort and do I need a prescription?

You do not need a prescription to buy St. John’s Wort, but we would strongly advise you use it under our supervision. Please speak to one of the vets if you would like to discuss its use in your animal. We would be happy to advise.

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