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Nov 28, 2009
Pergolide 101
Available here in Printable Format
Contents:
What is Pergolide?
Formulations of Pergolide
Storing
Dosage
Tapering
Side Effects
Pergolide Sources
How to Get Them to Eat It
Warnings
What is Pergolide?
Pergolide (pergolide mesylate) controls the out-put of a hormone called ACTH. If ACTH is not controlled, it means the pituitary tumor is growing unchecked. To obtain pergolide you will need a prescription from your vet once blood tests (http://tinyurl.com/2kqu5v) have been run and high ACTH levels have been verified. Pergolide should never be administered to a horse with normal blood levels of ACTH. However, no PPID test is perfect and with a difficult to control laminitis case, your veterinarian may decide a trial of pergolide is warranted.
Once you have a prescription in your hand, you can obtain pergolide from many sources. Pergolide used to be very expensive and even today if cost is a concern, you may want to compare prices at different compounding pharmacies. There is a list of compounding pharmacies (http://tinyurl.com/yg4y38b) compiled by group members, in the Database section of the EC&IR Group.
Remember to obtain and save a copy of lab results from your vet so you have an accurate record of ACTH levels. At least if you get behind in updating your horse’s Case History (http://tinyurl.com/yknwhk7) you’ll have all the numbers and units to update with.
For more information see:
Acth Testing & Information (http://tinyurl.com/335t73)
Blood Testing for IR & Cushings Disease (http://tinyurl.com/2kqu5v)
Sending Blood Work To Cornell (http://tinyurl.com/yf56cqf)
Prescriptions -- Is your vet required to give you a prescription? (http://tinyurl.com/yw4te)
Seasonal Rise (http://tinyurl.com/yfnqrb5)
Pergolide Facts EC&IR message # 135349 (http://tinyurl.com/ykfoeku)
Formulations
There are several formulations for pergolide available: liquid, loose powder and capsules. Some vets are not aware that pergolide formulation is vitally important to the shelf life of the drug. There is no benefit to the horse or cost saving if the drug is inert. Save yourself time, money and grief by insisting on a prescription for the formulation that best suits your needs. In general, encapsulated pergolide powder is the most economical and stable
- Encapsulated Powder: This is the formulation of choice for the EC &IR Group because the added barrier to air and humidity provides up to 6 months of pergolide stability. Additionally since the dosage is done by the pharmacy, it is very accurate.
- Liquid Pergolide: Anytime pergolide is exposed to water it has 14 days before expiration.[i] When water is used as a carrier it must be stored in the fridge to prevent things from growing in the bottle[ii]. However, to remain stable pergolide must be kept at room temperature.
- Loose Powder: Though cheaper, with a longer shelf life than liquid it is easier to measure dosage changes with than capsules. However the powder is exposed to humidity and air each time the bottle is opened, and this decreases the potency over time. There also is the added problem of the carrier settling in the container making the dosage inaccurate.
See Also:
Communicating with your Vet (http://tinyurl.com/ygx3qaw ) From TheHorse.com - to access this article, you must first register on the site (free), then enter article 273 in article quick find.
Storage
Pergolide should be kept at room temperature protected from humidity (in its container). Some members keep long time supply, in a double container and put a week or two worth of capsules in a smaller container. Another thing to remember is that freezing will greatly reduce the potency of your pergolide so in winter if it is being delivered by courier or mail, be sure to watch for the delivery person.
Dosage
“The only "correct" dose of pergolide is the one that controls his ACTH.”
- Dr. Kellon EC&IR Message 132610 Sep 2, 2009
Once a horse is diagnosed with PPID, he will be on pergolide for the rest of his life. Diagnosis of PPID is determined by blood levels of ACTH being higher than lab reference ranges but not during the fall seasonal high.
Most horses are started at 0.5 mg per day, but many horses, especially advanced cases require more, up to and possibly beyond 6mg.
There are two ways to judge if your pergolide dose is correct. One is by careful monitoring of the horse’s physical symptoms. The other, though more costly but more accurate, is by blood tests used to monitor the level of the hormone ACTH in the horse’s blood stream (http://tinyurl.com/2kqu5v).
How to monitor physical symptoms to determine pergolide dosage:
Though not as accurate as blood tests, for various reasons, costs not being the least, some EC&IR Group members choose to monitor physical symptoms to determine dosage. Careful daily observation is needed. This may be difficult for owners who board or who are not involved in the day-to-day care of the horse. It is vital that owners know all the symptoms of both PPID and Insulin Resistance because out of control PPID causes Insulin Resistance.
Symptom monitoring is subjected to individual interpretation. Words like large, small, excessive etc. mean different things to different people. For a really great way of measuring changes in your horse’s symptoms please see EC&IR Message # 111988 (http://tinyurl.com/yj2es39).
It is important, though not essential, to know what is normal for your horse. For example owners sometimes monitor their horses without being able to discern any difference in symptoms because while high enough to prevent laminitis, the dosage isn’t high enough to bring about a change in physical symptoms.
See also:
For a list of physical symptoms see:
How to use ACTH blood tests to determine pergolide dosage:
Monitoring the ACTH levels to determine the pergolide dosage’s effectiveness should be done on a regular schedule. In all horses, ACTH production rises between August and December and lowers between the months of January and July. When checking ACTH levels to determine if pergolide is controlling ACTH, to prevent seasonal hormonal influences from skewing the ACTH test results, blood should be drawn and tested at the same time as previous years. (For example, run tests yearly in the 3rd week of August or the last week in July etc.) Note: Testing ACTH just before grass actually starts to grow in spring is not recommended as it is suspected that a huge hormonal upset occurs at this time (see EC&IR Message # 123435 - http://tinyurl.com/ydjbodr).
Diagnosis of PPID is based on high ACTH but only during the naturally low ACTH season. This has lead to a mistrust of results of tests run in the fall. However, when it comes to dosage, there are no “false” highs, especially when preventing laminitis is the goal. ACTH naturally runs high in fall making it the most important season to run dosage check ACTH tests.
At the minimum an ACTH test should be run in late summer (August) and pergolide dosage adjusted. Two to four weeks after target dosage has been reached another ACTH test should be run to ensure the ACTH is being controlled
Always watch your horse carefully for symptoms of both IR and PPID. Run ACTH tests when/if you see him back sliding.
For more details and hints see:
How long to wait to retest after changing dosage or starting pergolide?
When testing ACTH for dosage accuracy you should wait two to four weeks after the target dosage has been reached. This time frame is used because it is the amount of time it takes for symptoms to return after a horse has been taken off pergolide.
See also:
Tapering
Whether increasing or decreasing dosage or just starting pergolide for the first time, to reduce the chances of your horse experiencing side effects it is recommended to taper to the targeted dosage. The EC&IR Group recommends a tapering rate of .25 mg over for three days. Ordering a supply of 18 0.25 mg capsules makes tapering easier.
If aiming for an increase of 1 mg dose:
Day 1 to 3: increase by one 0.25 mg capsule - total of 3
Day 4 to 6: increase by two 0.25 mg capsules - total of 6
Day 7 to 9: increase by three 0.25 mg - total of 9
Day 10 - start full 1 mg
For a list of side effects see:
START HERE (http://tinyurl.com/ya4neyr)
New Member Primer
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Side Effects
There are basically two different common (but temporary) side effects that are caused by pergolide: depression and lack of appetite. This is known as the “pergolide veil”. When first starting pergolide some horses feel much better right away but others are affected by the pergolide veil for about 2 weeks. This is a hard time for owners as the horse certainly appears to not like beet pulp or the soaked and safer hay. Hang in there – they do get over it. Once the horse gets used to being on pergolide, he will start to eat normally again, eventually even to like the “yucky” food he is refusing now.
Meanwhile, there are a few things you can do to help your horse during this adjustment period. You can try different flavorings (links below) to tempt the horse to eat but the best thing to do is taper your dosage changes. If tapering and taste tempters fail, adaptogens can help. Adaptogens are natural substances that help the body block negative responses to chronic stress. Two types are APF and Canadian Ginseng. (Note: Other ginsengs can cause elevated insulin Canadian Ginseng is the one to use.) APF though more expensive than Canadian ginseng has a great track record in the EC&IR Group for helping with pergolide veil.
See also:
8 Pulling it Together (http://tinyurl.com/ya6sflv)
Picky eater's checklist (http://tinyurl.com/ya6sflv)
Introducing New Feeds and Supplements (http://tinyurl.com/ya6sflv)
Treats for Horses (http://tinyurl.com/yku6f7y)
APF (http://tinyurl.com/yj575hq)
ADAPTOGENS
APF
How to Get Them to Eat It?
If the drug isn’t getting into the horse, there is no benefit.
During the pergolide veil many horses will not take anything slightly suspicious. It is okay to mix pergolide with water or yogurt and syringe it in. Once the horse is over the pergolide veil, things do get easier. Safe treats often can be used to hide the pergolide.
Some members put pergolide powder on wet beet pulp. The drawback to this method is that sometimes horses dribble food – especially if not being fed by hand – making it impossible to tell if the horse ingested the full dose.
The secret is to find a carrier that is as safe as possible and works for your horse and you. Some members resort to “no-no” treats. This method might be dangerous especially if your horse is border-line laminitic so if you feel you have to go that route, use as little unsafe treats as possible.
Some horses spit out the capsule. More of the carrier fed after the capsule has gone in the horse’s mouth often helps this problem.
See Also:
Treats for Horses (http://tinyurl.com/yku6f7y)
EC&IR Group Message #135684 (http://tinyurl.com/yklsdzn)
Warnings
Acepromazine is a dopamine antagonist so it counteracts pergolide. A single dose for a veterinary procedure isn't a big issue, but it may be a consideration if the vet puts a horse on ace several times a day as a vasodilator for laminitis. This is a judgment call for the vet.
See Also:
Drugs, Pergolide, Cushings Disease Treatments (http://tinyurl.com/2alwqb)
Drugs -- Pergolide Interaction with ACE, etc.
Supplements and Drugs to Avoid with Cushings Horses
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[i] Ian Hudgings, Vet Pet Solutions EC&IR Message #106111 (http://tinyurl.com/yjlqsuv)
[ii] Ian Hudgings, Vet Pet Solutions & ThrivingPets.com EC&IR Message # 112535 (http://tinyurl.com/ygx6q47)
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