Just lately, I decided to educate myself on the subject of bute. You know what I’m referring to – that handy tube of paste, or container of powder, or liquid form which we frequently reach for when a horse in our care indicates it is in some form of pain, soreness or distress.

Phenylbutazone (Bute) is a NSAID (non-steroidal anti-inflammatory drug) given for multiple reasons including swelling, soreness, musculosketetal pain and lameness including laminitis. If you have owned horses for even a short period of time, it is more than likely that you have either had to give a dose yourself, or known a horse who was prescribed bute. As common as this drug may be, it is easily misunderstood, and there are more than a few misconceptions surrounding it’s administration, effectiveness and general use.

As it turns out, I learned we as horse owners, need to be careful in the administration of bute. That it is not, in fact, the equine equivalent to Advil, which is a common misconception. So, without further ado, here are 11 points of information we all oughta’ know – about bute.

1) The three forms of bute: paste, granulars (powder), and injections.

Paste: This form of bute has been marketed as one of the easiest methods of administering the medication to your horse. Some studies note that paste is absorbed in horses faster than with powder formulas, however, other studies suggested that both methods led to approximately the same absorption. It is generally accepted that bute in paste form will reach minimum therapeutic levels (meaning the minimum amount to start decreasing inflammation) in about an hour.

What you may not realize is that the paste may not reach the maximum concentration – meaning the entire dosage absorbed in the body – for up to 18 hours. And, a factor which may delay the absorption of the med is the the feeding of hay.

The effects of bute in paste generally seem to last around 8-12 hours.

Granular: The powdered forms of bute were decidedly similar to those of paste in terms of absorption and effect, with some research suggesting granulars had a slightly slower absorption rate.

Injection: Bute injected intravenously is the sure-fire method of reaching maximum concentration in the fastest time – sometime between 1-3 hours, and will last as long as paste – between 8-12 hours. Remember, injections should be left to veterinarians or trained animal health technologists.

Bute in all its forms, provides the identical duration of pain relief – 8 to 12 hours.

2) Bute and ulcers – a high risk.

The risk of ulcers when medicating your horse with bute is very real, and dangerously common. While NSAIDs as a group are known to cause gastric and colonic ulcers, bute is more likely to cause ulcers than any other. This is because the drug inhibits prostaglandins, to reduce swelling and inflamation, but also a prostaglandin that plays a vital role in protecting the gut lining. Horses on vet-recommended doses of bute have been shown to develop ulcers in as little as five days. When given orally, bute can also cause ulcers in the mouth and esophagus.

Bottom line: if you are administering bute for any prolonged period of time, be sure you are aware of the symptoms of ulcers in horses, and have the direction of a veterinarian to counsel you. Often with extended treatment, bloodwork is recommended and giving the horse a break off bute for short periods of time is suggested.

3) A word about side effects.

Dr. Jordan Cook of Moore & Co. Vet Clinic has this to say about common dosing with bute.

“Using bute ‘here and there’ is all too common and comes with greater risks than people often realize. Overdosing occurs frequently, more is not better in this case and can have detrimental effects. Unfortunately the rate of occurrence of side effects (ulcers, colic, kidney problems) varies horse to horse. Some horses can tolerate (anecdotally) accidental administration of very high doses whereas others begin to show bloodwork changes and clinical signs after a few days on average doses.”

4) There is no bute on the market with an added ulcer preventative.

There are however, ulcer remedies, both herbal and pharmaceutical, which can be taken in conjunction with bute.

5) There are shipping regulations regarding horses and bute.

Bute is a banned substance for any equine intended for human consumption, therefore horses intended for slaughter, with a record of bute administration will be stopped at the Canadian/U.S. border.

6) Bute is not the horse equivalent of Advil (ibuprofen).

Technically both medications are NSAIDS, used for treating inflammation and pain caused by such swelling and inflammation. However, the side effects for bute are far more serious than for any Advil or Tylenol we would take ourselves. In one study, even 50% more than the maximum dose, when given to a horse, caused death within a week. The dosage window for bute is, in fact, very small. So while we might be of the mind frame that bute is equal to one or two Advils, we owners should really be under the advice of a veterinarian before administering it.

7) Humans should never ingest bute themselves, not even in an emergency.

You’re on a trail ride deep in the mountains. An accident occurs. And, it’s you, not your horse who needs the pain relief. Unfortunately, your emergency kit contains only bute. Can you consume the bute? NO, NO and NO. Listen up. Every resource consulted stated that humans must never ingest bute, as the side effects can be crazy-serious for us humanoids. It is know to be toxic to humans, cause bone marrow loss and anemia. Bute is also a known carcinogen, and so must be treated as such. Therefore, your inflammatory emergency is just going to have to wait until you can get back to your own medicine cabinet.

Photo by Kvetina-Marie

8) Bute and babies not a desirable combination.

Bute can pass through the placental lining and also into the milk of a mare, therefore some of your dosage is getting to the foal. Because their systems are not fully developed, foals will exhibit ulcers and kidney problems far more rapidly than full grown horses, and it is extremely easy for them to accumulate toxic amounts in their systems. Bute is also potentially toxic to developing embryos, so use caution with mares that have recently been bred, or are confirmed in foal.

9) Always consult your veterinarian before deciding to give your horse a left-over dosage of bute.

Everyone who has had a horse prescribed bute knows that there is usually a couple doses left over. It is tempting to just give an extra dose when one horse comes up lame, or exhibits swelling. However, resist the temptation to owner-medicate your horse, and call your vet before giving any horse even one dose of bute. Your vet can help you decide if indeed the horse could be helped by the medication, and also the dosage size.

10) Bute is not for every horse, or every situation.

Remember, that with any anti-inflammatory such as bute, you are treating the symptom and not the problem. Although signs of lameness and swelling may be reduced by bute, it does not mean that the root of the problem has been fixed. It is dangerous to give bute to horses that have suspected fractures, as they may further injure themselves once on pain relief. It is also not intended for treating infections. Lastly, the effects of bute can be especially problematic for horses with pre-existing conditions such as ulcers, kidney problems or bleeding conditions. If your horse is on other medications, bute may limit or displace the intended actions.

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And finally, one more tidbit.

11) You cannot bake bute into horse treats.

Just in case you were thinking of it. . . heat will inactivate the medicinal ingredients of bute.

~ Thanks to Western Horse Review editorial intern Amie Peck for the research conducted for this post, and Dr. Jordan Cook of Moore & Co Large Animal Clinic, for the “vet-check.”