What Is Citalopram?
Although data on the use of citalopram in companion animals is extremely limited at this time, this drug offers another adjunctive treatment option to manage behavioral disorders in dogs and cats.
This information is intended to serve as an introduction to citalopram, which may be an unfamiliar drug for many clinicians. Full drug information, including possible interactions, available dosage forms, and a client handout, can be found at Plumbs.com (paid subscription required).
Pharmacology of Citalopram
Citalopram is a selective serotonin reuptake inhibitor (SSRI) with little effect on norepinephrine or dopamine reuptake and very little activity at muscarinic or H1-histaminergic receptors.
Contraindications of Citalopram
Citalopram is contraindicated in dogs and cats that are hypersensitive to it or have received a monoamine oxidase inhibitor within 14 days.
Adverse Effects of Citalopram
Information about the adverse effects of citalopram is limited. In a case series of 9 dogs, adverse effects included sedation (3 dogs), loss of appetite (2 dogs), and constipation (1 dog).1 In cats, citalopram adverse effects are likely similar to other SSRIs and might include sedation, decreased appetite/anorexia, vomiting, diarrhea, behavior changes (eg anxiety, irritability, sleep disturbances), and changes in elimination patterns.
Appropriate Use of Citalopram
Citalopram is not considered a first-line agent for these conditions in either species and may be considered when more commonly used drugs (eg, clomipramine, fluoxetine) have failed or adverse effects preclude use. A 6- to 8-week trial is usually recommended before assessing efficacy and/or dose adjustment.
Dogs
Adjunctive treatment (with behavior modification) of aggression, anxiety, and compulsive behavior disorders is extra-label.
Cats
Anecdotal administration in cats suggests citalopram may be useful for behavior disorders related to aggression, anxiety, compulsive behaviors, and urine marking[JB1] .
Additional Information
There has been interest in using escitalopram, the active S-enantiomer of racemic citalopram, in veterinary patients; however, data are extremely limited.
For more information on aggression, read the Clinician's Brief articles on Canine Aggression Toward Other Dogs & Humans and Feline Aggression; or, take a deeper dive into aggression in dogs and aggression in cats provided by the experts at Standards of Care (paid subscription only).