Hi, Debora - There have been a small number of misdiagnosed horses who were started on pergolide, but did not need it.  We have no firm data (beyond the anecdotal), but it would appear that most have no effects, and  some have more of a pergolide veil than one would suspect.  Since there has been a marked improvement since starting pergolide, I would say that the owner can quite safely stay on pergolide for now.  If there will never be any testing done, it becomes a little harder to know what dose of pergolide will work for this horse; however, many people successfully manage their horse's PPID, dosing by clinical signs. Given the horse's positive response to pergolide right now, at the beginning of the seasonal rise, your client could reasonably expect to increase the pergolide over the winter, and should be alert to any signs that show the necessity for an increase: goopy eyes, bigger/harder crest, more footsoreness, dirty sheath (ie, more sheath secretions), increased urination and drinking.  This, of course, assumes that the IR diet is tight and in place.

What can and *will* do damage is riding so soon after frank laminitis.  It takes 9  to 12 months for a full hoof growth cycle (I know you know this - this is for others reading)  One should not ride a horse who has had frank laminitis until there is a 1/2 to 3/4 growth cycle. That is 6 to 9 months, depending on the horse. Really frightful founders should not be ridden for a full year.  There is a ton of gentle ground work that can be done (no tight circles, no hard ground, use hoof boots);  but definitely no riding. Even when the trim is superb, those laminar attachments are fragile, and will tear loose until there is adequate growth and tight attachment.

IR and PPID horses can be managed effectively without multiple vet visits and bloodwork, but it is a big commitment in observation and management.  In a perfect world, we would all get bloodwork done 3 times a year or more.  I totally get it that not everyone can do this.  However, I would strongly urge not to ride this horse until after Christmas, at the very earliest.