Clomipramine (Clomicalm) for Dogs and Cats: Behavioral Dosing, Efficacy, and Safety

Bottom line

Clomipramine is a tricyclic antidepressant (TCA) whose only FDA-approved indication is canine separation anxiety in dogs older than 6 months, as part of a comprehensive behavioral management program — never as monotherapy [1]. It is used off-label for feline urine marking and for canine and feline compulsive disorders (e.g., acral lick dermatitis, tail chasing, feline psychogenic alopecia) [3][4][6]. Onset is slow: expect typically 1–4 weeks, sometimes longer, for full effect, so pair every prescription with a behavior-modification plan and set owner expectations accordingly [6].

Drug facts

• Class: Tricyclic antidepressant (dibenzazepine).
• Mechanism: Inhibits reuptake of both serotonin and norepinephrine; the active metabolite desmethylclomipramine is comparatively more noradrenergic. Clomipramine also carries meaningful anticholinergic, antihistaminic, and alpha-1-adrenergic-blocking activity, which drives much of its adverse-effect profile [5][6].
• Formulations: Clomicalm (clomipramine hydrochloride) tablets are available as 5, 20, 40, and 80 mg [1].
• FDA-approval status: Approved in the US (Clomicalm) for the treatment of separation anxiety in dogs greater than 6 months of age as part of a comprehensive behavioral management program [1]. Use in cats is off-label [4][6].
• Label indication (dogs): Inappropriate barking, destructive behavior, and inappropriate elimination associated with separation anxiety may be alleviated when clomipramine is combined with behavior modification [1].
• Key label contraindications/cautions: Prior hypersensitivity to TCAs; concurrent or recent (within 14 days) MAOI use; history of seizures or concurrent seizure-threshold-lowering drugs; use with caution in cardiovascular disease and in narrow-angle glaucoma / raised intraocular pressure; not for male breeding dogs [1].

Dosing

Dose by species and indication, and flag the off-label uses explicitly. Titrate from the low end and reassess at 4–6 weeks before judging efficacy [5].

Canine separation anxiety (FDA-approved, on-label). The Clomicalm label dose is 2 to 4 mg/kg/day PO, given as a single daily dose or divided every 12 hours, adjusted to patient response and tolerance, always alongside a behavior-modification program in dogs >6 months [1]. In the registration trial the effective arm used 1 to <2 mg/kg PO q12h (i.e., 2 to <4 mg/kg/day) [2].

Canine compulsive disorder (off-label). The pivotal crossover trial dosed clomipramine at 3 mg/kg PO q12h [3]. Formulary sources generally support roughly 1–3 mg/kg PO q12h for canine compulsive/stereotypic behavior, titrated to effect [5].

Feline urine marking / compulsive disorders (off-label). In the feline dose-determination RCT, the recommended initial dosage was 0.25 to 0.5 mg/kg PO q24h, within a studied range of 0.125–1 mg/kg once daily [4]. Cats are dosed lower and less frequently than dogs; do not extrapolate canine mg/kg figures to cats [4][6].

Do not stop abruptly after chronic use — taper to reduce withdrawal/rebound [5].

Efficacy evidence

Canine separation anxiety — the strongest data. In the multicenter, randomized, double-blind, placebo-controlled registration trial (King et al., 2000; 95 dogs, all receiving behavior therapy), dogs on standard-dose clomipramine plus behavior therapy were rated improved at least three times faster for destruction, defecation, and urination than dogs on placebo plus behavior therapy — evidence that drug plus behavior modification outperforms behavior modification alone [2]. Two caveats temper this: the low-dose arm was not significantly better than placebo, and vocalization did not improve significantly over placebo [2].

Canine compulsive disorder. Hewson et al. (1998) ran a randomized, placebo-controlled, double-blind AB-BA crossover in 51 dogs at 3 mg/kg q12h; clomipramine significantly reduced compulsive behavior versus placebo but 4 weeks was not curative, reinforcing that behavior modification is required for durable control [3].

Feline urine marking. King et al. (2004) treated 67 neutered cats and found all three clomipramine dosages significantly reduced spraying frequency versus placebo, supporting the 0.25–0.5 mg/kg q24h starting dose, with most cats that respond showing meaningful reductions in spraying [4]. As of 2026, feline evidence remains smaller and shorter-term than the canine separation-anxiety dataset, and relapse on discontinuation is common, so frame feline use as adjunctive and often long-term [4][6].

Adverse effects

Most effects are dose-dependent and reflect anticholinergic and monoaminergic activity [5][6]:

• Sedation / lethargy — common early, often attenuates.
• Anticholinergic: dry mouth (reduced salivation), constipation, urinary retention, mydriasis, reduced lacrimation [6].
• GI upset: vomiting and diarrhea, usually mild and transient [1][6].
• Hepatic: transient elevations in liver enzymes have been reported [5].
• Cardiac: dose-dependent conduction effects (tachyarrhythmias, potential QT/conduction changes) at higher exposures [6].
• Neurologic: lowered seizure threshold — clinically relevant in predisposed patients [1].
• Rare idiosyncratic reactions occur; discontinue and reassess if severe.

Contraindications and interactions

• Hypersensitivity to clomipramine or other TCAs [1].
• MAOIs — do not co-administer. Avoid within 14 days before or after an MAOI because of serotonin-syndrome risk [1]. In veterinary practice this includes selegiline / l-deprenyl (e.g., for canine cognitive dysfunction or Cushing's) and amitraz-containing products (demodicosis dips, some tick collars), which have MAOI-like activity [1][5].
• Seizure history / seizure-threshold-lowering drugs — contraindicated per label; clomipramine lowers the seizure threshold [1].
• Cardiac arrhythmia / conduction disease — use with caution given TCA conduction effects [1][6].
• Narrow-angle glaucoma or raised intraocular pressure, and urinary or GI retention/obstruction — anticholinergic activity can worsen these [1][6].
• Hepatic impairment — clomipramine is hepatically metabolized; use cautiously and monitor [5].
• Additive serotonergic effects with SSRIs (e.g., fluoxetine), SNRIs, tramadol, trazodone, and other serotonergic agents raise serotonin-syndrome risk; combine only with specialist oversight and dose caution [5].
• Additive anticholinergic/sedative effects with antihistamines, phenothiazines, and other anticholinergics [6]. Hepatic CYP-metabolized drugs can alter clomipramine exposure [5].

Monitoring

• Take a thorough baseline behavioral history and confirm the diagnosis and behavior-modification plan before prescribing [1][6].
• Consider baseline CBC/serum chemistry (including hepatic enzymes) and cardiac auscultation ± ECG in older patients or those with cardiac, hepatic, or seizure risk [5][6].
• Reassess at 4–6 weeks — the earliest reliable point to judge behavioral response — and periodically thereafter [5].
• Taper rather than abruptly discontinue after chronic dosing [5].

Alternatives and where it sits

Clomipramine is one of two evidence-supported first-line oral agents for chronic canine anxiety and compulsive disorders; the other is the SSRI fluoxetine, which shares the serotonergic mechanism with a cleaner (less anticholinergic/cardiac) profile and is often preferred when comorbid cardiac disease, glaucoma, or urinary retention is a concern — see fluoxetine for canine behavior. For acute, situational anxiety (thunderstorms, vet visits, post-op confinement) where a daily maintenance TCA is unnecessary, situational trazodone is the usual choice — see trazodone for dogs. For dog separation anxiety and noise aversion, the newer alpha-2A agonist tasipimidine is an alternative worth knowing — see tasipimidine for noise aversion and separation anxiety. In cats, clomipramine competes chiefly with fluoxetine and, for marking specifically, with buspirone — see buspirone for feline anxiety and urine marking.

Frequently Asked Questions

What is the clomipramine dose for cats?

For feline urine marking, the studied starting dose is 0.25 to 0.5 mg/kg PO once daily, established in a dose-determination RCT of 67 cats; the tested range was 0.125–1 mg/kg q24h [4]. This is off-label — clomipramine is not FDA-approved in cats — and cats are dosed far lower and less often than dogs, so never scale canine mg/kg figures to a cat [4][6].

How long until clomipramine works?

Full behavioral effect typically takes 1–4 weeks, sometimes longer [6], so reassess at the 4–6-week mark before deciding it has failed [5]. Because of this lag, clomipramine is a maintenance drug, not a same-day anxiolytic — reach for situational trazodone when you need an effect within hours [6].

Can you combine clomipramine with fluoxetine?

Generally avoid stacking two potent serotonin-reuptake inhibitors: clomipramine plus fluoxetine produces additive serotonergic effects and raises serotonin-syndrome risk [5]. Switching between them, rather than combining, is the usual approach; any deliberate combination should be reserved for refractory cases under behaviorist supervision with careful dose reduction and monitoring [5].

Clomipramine vs fluoxetine for separation anxiety?

Both have veterinary approvals for canine separation anxiety and both must be paired with behavior modification [1][2]. Clomipramine (a TCA) carries more anticholinergic and cardiac-conduction burden, whereas fluoxetine (an SSRI) generally has a cleaner tolerability profile; drug choice often turns on comorbidities (favor fluoxetine with cardiac disease, glaucoma, or urinary retention) and prior response [1][6].

Is a washout needed after an SSRI or MAOI?

After an MAOI — including selegiline/l-deprenyl and amitraz products — observe at least a 14-day washout before or after clomipramine because of serotonin-syndrome risk [1][5]. When transitioning from an SSRI such as fluoxetine, there is no fixed label interval, but taper and allow a washout appropriate to that drug's long half-life to avoid additive serotonergic toxicity [5].

Is clomipramine safe in a dog with a history of seizures?

No — the label contraindicates clomipramine in dogs with a seizure history or on drugs that lower the seizure threshold, because TCAs reduce that threshold [1]. In an epileptic patient needing behavioral pharmacotherapy, choose an agent without this liability and coordinate with the seizure-management plan [1][6].

Can clomipramine be used as monotherapy?

No. Every indication — approved canine separation anxiety and off-label compulsive/marking uses — requires concurrent behavior modification; the trials showed the drug alone was not curative [1][2][3]. Prescribing clomipramine without a behavior plan is off-protocol and predictably underperforms [2][3].

What is the clomipramine dose for canine separation anxiety?

The Clomicalm label dose is 2 to 4 mg/kg/day PO, as a single daily dose or divided q12h, titrated to response and tolerance in dogs >6 months, always with a behavioral management program [1]. The registration trial's effective arm used 1 to <2 mg/kg q12h [2]; start low, titrate, and reassess at 4–6 weeks [5].