Compulsive disorders in dogs: clomipramine or fluoxetine vs placebo — POSSIBLE

In dogs with compulsive disorders (including acral lick dermatitis), do clomipramine or fluoxetine vs placebo reduce compulsive behaviour frequency?

Shelf #301 · gate-verified and displayed under the developer's blinded-trial rule

POSSIBLE: Both drugs beat placebo in small double-blind trials, but the record is thin on magnitude. For fluoxetine, Wynchank & Berk 1998 randomised 63 dogs with acral lick dermatitis to fluoxetine 20 mg daily or placebo for 6 weeks: owners rated both lesion appearance and licking behaviour as significantly improved on fluoxetine (t = 10.2, df = 29, P < 0.0001 for each) and veterinarian-rated photographs also improved significantly, with no significant change on placebo. For clomipramine, Hewson 1998 randomised 51 dogs with canine compulsive disorder in a double-blind, balanced AB-BA crossover to clomipramine (3 mg/kg PO q 12 h) for 4 weeks and placebo for 4 weeks: both validated owner rating scales demonstrated a treatment effect, but the abstract reports no numeric effect size, and treatment for 4 weeks was not curative — of 45 dogs re-evaluated 1 to 2 years later, all still had their behaviours. Sedation and reduced appetite were reported more commonly on clomipramine than on placebo. Rapoport 1992 adds class support — in double-blind crossover comparisons the serotonin uptake blocking drugs were clinically effective while the comparators were not — but its clomipramine and fluoxetine arms were compared with active drugs, not placebo, and its abstract gives no numbers, so it does not itself carry the vs-placebo claim. Two small positive trials with one unquantified result is POSSIBLE, not more. Drafted Nov 10, 2026 (VetMed build, topic #301); all figures from abstracts fetched and verified at drafting.

Hewson 1998: clomipramine showed a treatment effect on both owner rating scales vs placebo in 51 dogs with compulsive disorder — magnitude not reported

Randomized, placebo-controlled, double-blind, balanced AB-BA crossover clinical study (record's own design wording)

Who: Dogs: 51 dogs with canine compulsive disorder (behaviours included spinning, n = 17, and self-mutilation by licking / acral lick dermatitis, n = 12) in a clinical study — breed and setting beyond the clinical caseload are not stated in the record. Each dog received clomipramine (3 mg/kg PO q 12 h) for 4 weeks and placebo for 4 weeks in balanced AB-BA crossover order.

Result: Both validated owner rating scales demonstrated a treatment effect for clomipramine over placebo (statistical analysis by ordinal regression); the abstract reports no numeric effect size, response rate, or p-value. Compliance was satisfactory and masking was effective. Sedation and reduced appetite were reported more commonly when dogs were given clomipramine than when given placebo. Forty-five dogs available for follow-up 1 to 2 years after completing the study still had their behaviours (6 dogs were lost to follow-up), and the authors conclude that 4 weeks of treatment was not curative and behaviour modification is likely to be necessary.

Watch out: The claim-carrying result is unquantified in the record — 'a treatment effect' on two ordinal scales, with no size given — which is a main reason this shelf is POSSIBLE rather than higher. This is a crossover, so each dog is its own control; there is no separate parallel placebo group.

Hewson CJ, Luescher UA, Parent JM, Conlon PD, Ball RO. Efficacy of clomipramine in the treatment of canine compulsive disorder. J Am Vet Med Assoc. 1998;213(12):1760-6. PMID: 9861971. Registry ID: none in the record. MeSH: Animals · Antidepressive Agents, Tricyclic/adverse effects,pharmacology,therapeutic use · Appetite/drug effects · Behavior, Animal/drug effects · Clomipramine/adverse effects,pharmacology,therapeutic use · Compulsive Behavior/drug therapy · Cross-Over Studies · Dog Diseases/drug therapy · Dogs · Double-Blind Method · Drinking/drug effects · Female · Male · Odds Ratio · Sleep/drug effects · Vomiting/chemically induced,veterinary

Wynchank & Berk 1998: fluoxetine improved lesion appearance and licking vs placebo in 63 dogs with acral lick dermatitis (P < 0.0001)

Placebo-controlled randomized double blind trial (record's own title wording)

Who: Dogs: 63 dogs with acral lick dermatitis — breed and clinic setting are not stated in the record — treated with fluoxetine 20 mg daily or placebo for 6 weeks.

Result: In the fluoxetine group, owners rated both appearance of the lesion (t = 10.2, df = 29, P < 0.0001) and licking behavior (t = 10.2, df = 29, P < 0.0001) as significantly improved by the end of the trial. Veterinarian-rated pre- and post-treatment photographs showed statistically significant improvement in the fluoxetine group (mean = 2.55, on a scale the abstract does not define). There were no significant changes in the placebo group as rated by owners and veterinarians. The authors conclude the results demonstrate the efficacy of fluoxetine in acral lick dermatitis.

Watch out: Outcomes are owner ratings and photograph ratings, not counted licking episodes, so 'compulsive behaviour frequency' is measured indirectly. The identical t-value (10.2) for both owner outcomes is reproduced exactly as printed in the record. The abstract gives no per-group denominators, no absolute improvement rates, and no adverse-event numbers, so no absolute benefit can be computed from the record.

Wynchank D, Berk M. Fluoxetine treatment of acral lick dermatitis in dogs: a placebo-controlled randomized double blind trial. Depress Anxiety. 1998;8(1):21-3. PMID: 9750975. Registry ID: none in the record. MeSH: Animals · Antidepressive Agents, Second-Generation/pharmacology,therapeutic use · Dermatitis/diagnosis,etiology,veterinary · Disease Models, Animal · Dog Diseases/diagnosis,drug therapy · Dogs · Double-Blind Method · Female · Fluoxetine/pharmacology,therapeutic use · Grooming/drug effects · Male · Mental Disorders/veterinary · Obsessive-Compulsive Disorder/complications · Reproducibility of Results · Treatment Outcome

Rapoport 1992: serotonin uptake blockers were clinically effective in 42 dogs with acral lick — but clomipramine and fluoxetine were compared with active drugs, not placebo

Double-blind crossover comparisons (record's own abstract wording; MeSH: Double-Blind Method)

Who: Dogs: 42 dogs with severe chronic canine acral lick dermatitis — breed and setting are not stated in the record — treated in three double-blind crossover comparisons: clomipramine hydrochloride / desipramine hydrochloride, fluoxetine hydrochloride / fenfluramine hydrochloride, and sertraline hydrochloride / placebo.

Result: The serotonin uptake blocking drugs were clinically effective, while the other drugs were not. The abstract reports no numeric results, group sizes per comparison, or p-values. On phenomenology and pharmacological response the authors propose canine acral lick dermatitis as an animal model of obsessive-compulsive disorder.

Watch out: This record does NOT test clomipramine vs placebo or fluoxetine vs placebo: those two drugs were each compared with another active drug, and only sertraline had a placebo comparator. It is carded as class-level supporting evidence only, not as a vs-placebo trial of the shelf's named drugs. Randomisation is not stated in the record, so none is claimed for this card.

Rapoport JL, Ryland DH, Kriete M. Drug treatment of canine acral lick. An animal model of obsessive-compulsive disorder. Arch Gen Psychiatry. 1992;49(7):517-21. PMID: 1385694. Registry ID: none in the record. MeSH: 1-Naphthylamine/analogs & derivatives,therapeutic use · Animals · Clomipramine/therapeutic use · Dermatitis/drug therapy,veterinary · Desipramine/therapeutic use · Disease Models, Animal · Dog Diseases/drug therapy,physiopathology · Dogs · Double-Blind Method · Fenfluramine/therapeutic use · Fluoxetine/therapeutic use · Follow-Up Studies · Grooming/drug effects,physiology · Humans · Neurotransmitter Uptake Inhibitors/therapeutic use · Obsessive-Compulsive Disorder/drug therapy,physiopathology · Serotonin/physiology · Sertraline · Ulcer/drug therapy,veterinary

Synthesis: two small double-blind placebo trials point the same way, one of them unquantified

Synthesis

Who: Synthesis of the cards above: dogs with canine compulsive disorder (Hewson 1998, 51 dogs, clomipramine crossover) and dogs with acral lick dermatitis (Wynchank & Berk 1998, 63 dogs, fluoxetine parallel trial; Rapoport 1992, 42 dogs, double-blind crossover comparisons).

Result: Fluoxetine has the cleaner vs-placebo result (significant owner- and veterinarian-rated improvement at 6 weeks, no significant placebo change); clomipramine has a demonstrated but unquantified treatment effect at 4 weeks, with sedation and reduced appetite more common and no cure — every followed-up dog still had its behaviour 1 to 2 years later. Clinically: either drug is a reasonable adjunct, behaviour modification remains necessary, and owners should expect control, not cure.

Watch out: No carded record counts compulsive episodes directly, none reports an absolute response rate, and follow-up beyond 6 weeks of treatment is limited to Hewson's 1–2-year behavioural persistence check. Effects in other compulsive presentations are extrapolated mainly from spinning and licking behaviours.

Synthesis of Hewson CJ et al. PMID: 9861971; Wynchank D, Berk M. PMID: 9750975; Rapoport JL et al. PMID: 1385694. Registry ID as on the individual cards.

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