PSYCHOPHARMACOLOGY
What's New - Does It Work?

Dr. Jeffrey A. LaCroix DVM
908 Pine Grove Drive
Wilmington, NC 28409

Spring 2000, Newsletter

The headline reads, "F.D.A. Approves First Antidepressant For Dogs." The advertising says, "Contrary to popular belief, the signs of old age aren't always signs of old age. Your dog may have Cognitive Dysfunction Syndrome (CDS), and we've got a pill for it!" What are these new drugs, and is there a place for them in Veterinary Medicine?

Actually, treating behavior disorders with drugs in dogs and cats is nothing new to veterinarians. Classes of drugs used to treat or modify behavior have included antihistamines, tranquilizers, mood stabilizers, anticonvulsants, progestins, stimulants, antidepressants, anxiolytics, narcotic a agonists and antagonists. Add to the list miscellaneous drugs including beta-blockers (used primarily to treat heart problems). With the exception of one or two tranquilizers and a hormone (progestin), none of these drugs have had the blessing of the F.D.A. for veterinary use.

The first of these drugs recently approved for veterinary use is Clomicalm by Norvartis Animal Health. This is a proprietary form of the drug clomipramine whose main use in psychaitry is the treatment of obsessive compulsive disorders such as canine lick granuloma, as well as general anxiety disorders including separation anxiety. Clomicalm is being advertised for the treatment of separation anxiety.

Dogs with separation anxiety exhibit signs such as destruction (chewing, digging), soiling (urination, defecation), or vocalization (barking, whining) when left alone. A dog with this disorder may follow you from room to room, become visibly upset when you get ready to leave, and greet you overenthusiastically when you return.

While certain medical problems can produce states of agitation, separation anxiety can, in most cases, be reasonably diagnosed from an accurate history. Drug therapy is not a "quick fix," and the manufacturer, Novartis, is "quick" to point this out. The drug is an adjunct to behavior modification designed to desensitize the dog to events producing anxiety.

The second of these two behavior modifying drugs approved for veterinary use is Anipryl (selegiline hydrochloride). Anipryl's original indication was for the treatment of Canine Cushing Disease (Adrenal Cortical Hyperfunction). With this disease, the adrenal glands work overtime producing excessive amounts of cortisone, usually because of erroneous commands from the pituitary gland. Anipryl tends to normalize these commands by increasing the amount and effectiveness of the brain chemical dopamine. It does this mainly by inhibiting another brain chemical known as monoamine oxidase type B (MOA-B). In people, MOA-B levels are known to increase not only with aging, but particularly in certain neurodegenerative disorders such as Parkinson's disease and Alzheimer's Disease.

Decreases in dopamine and increases in MOA-B may be responsible for some of the neurological signs of aging previously termed senility. It seems the term senility has become politically incorrect. Now, largely through the efforts of Pfizer - the maker of Anipriyl - we've been introduced to the term Cognitive Dysfunction Syndrome (CDS).

CDS is a clinical syndrome manifested by one or more of the following behavior problems in older dogs that cannot be attributed to an unrelated medical condition:

• Disorientation - wanders aimlessly, appears lost or confused, doesn't recognize familiar people
• Altered or decreased interaction with family - solicits attention less, no longer stands or lies for petting
• Decreased greeting behavior - no longer greets owners, less enthusiastic greeting
• Change in sleep-wake cycle - sleeps more overall, sleeps less at night
• Change in activity - increase in aimless activity, such as wandering or pacing
• Loss of house training - signals less to go outside, urinates or defecates indoors

In clinical studies, owners reported that 69-75% of dogs improved in at least one clinical sign after Anilpryl therapy. However, anyone familiar with statistics would not that, if we include enough signs with this syndrome, some will get better or worse simply as a random event.

In a University of California - Davis study, 62% of 11 - 16 year-old dogs displayed signs in at least one behavioral category associated with CDS. 100% of 16 year-old dogs displayed signs in at least one category. Thus 62% of dogs 11 - 16 years of age and 100% of 16 year-old dogs have CDS and are candidates for medication.

There is certainly a biological basis for the use of Anipryl for "senile," (oops!) I meant to say, dogs affected with cognitive dysfunction. Only time will tell what percent are truly improved with drug therapy.