Alprazolam

Alprazolam is a benzodiazepine anxiolytic used for short-term relief of fear, panic and situational anxiety in selected veterinary patients. It is particularly useful when anxiety occurs in recognizable episodes, such as noise or thunderstorm reactions, and may accompany a longer-term behavioral treatment plan. Veterinary use also includes selected feline anxiety disorders and equine behavioral applications.

Its principal effect is anxiolysis, with sedation and muscle relaxation varying by dose and individual. It can be incorporated into treatment plans that combine medication, environmental management and behavioral modification.

Group

Benzodiazepine anxiolytic

Mechanism of Action

Alprazolam binds to the benzodiazepine site of GABA-A receptors in the central nervous system. It acts as a positive allosteric modulator: it enhances the response to the inhibitory neurotransmitter GABA rather than replacing GABA or directly producing all of its effects independently.

Enhanced GABA-mediated chloride conductance increases neuronal inhibition and reduces excitability in circuits involved in fear, arousal and emotional responses. This produces anxiolysis and, with increasing exposure, sedation, skeletal-muscle relaxation and anticonvulsant effects characteristic of the benzodiazepine class.

The same central action can reduce behavioral restraint in some animals, explaining disinhibition or paradoxical reactions. Repeated exposure can produce tolerance and physical dependence; these are consequences of adaptation to enhanced inhibitory signaling rather than evidence that the underlying anxiety has resolved.

Dose Rates

Dogs

Use / stage	Dose	Route	Schedule	Instructions
Anxiety	0.025–0.05 mg/kg	PO	Every 8 h	Do not use in: Benzodiazepine hypersensitivity; May increase to 0.1 mg/kg if needed; use the separate escalation regimen.
Anxiety - dose escalation	0.1 mg/kg	PO	Every 8 h	Do not use in: Benzodiazepine hypersensitivity; Escalation after assessment of response.
Anxiety - frequent administration	Reference only	PO		Do not use in: Benzodiazepine hypersensitivity; Administration every 4–6 hours is described for selected patients, but the dose paired with that interval is not explicitly specified.
Panic anxiety	0.01–0.1 mg/kg	PO	As needed	Maximum 4 mg/day; Do not use in: Benzodiazepine hypersensitivity; Administer before the anticipated trigger when possible. Do not exceed 4 mg per dog in 24 hours. The daily cap requires tracking all administrations; this regimen is excluded from automatic calculation.
Separation anxiety	0.25–2 mg/animal	PO	Every 8–24 h	Do not use in: Benzodiazepine hypersensitivity
Storm phobia	0.02–0.4 mg/kg	PO	Every 4 h	Do not use in: Benzodiazepine hypersensitivity; As needed for a storm; this is a distinct alternative to the panic regimen, not an instruction to exceed its daily cap.
Storm phobia - low-dose adjunct	0.02 mg/kg	PO	Every 4 h	Do not use in: Benzodiazepine hypersensitivity; Give alprazolam 1 hour before an anticipated storm; repeat every 4 hours only as needed. Use with behavior modification and the separately prescribed clomipramine course. The 0.02 mg/kg amount applies to alprazolam, not clomipramine.
Phobias or night waking	0.01–0.1 mg/kg	PO	Every 6–12 h	Do not use in: Benzodiazepine hypersensitivity
Phobias or night waking - fixed alternative	0.25–2 mg/animal	PO	Every 6–12 h	Do not use in: Benzodiazepine hypersensitivity
Acute anxiety	0.05–0.1 mg/kg	PO	Every 8 h	Do not use in: Benzodiazepine hypersensitivity; Alternative schedule is as needed; give 30–60 minutes before a trigger.

Cats

Use / stage	Dose	Route	Schedule	Instructions
Anxiety	0.125 mg/animal	PO	Every 12 h	Do not use in: Benzodiazepine hypersensitivity
Anxiety - weight-based alternative	0.0125–0.025 mg/kg	PO	Every 8–12 h	Do not use in: Benzodiazepine hypersensitivity
Anxiety - higher-dose alternative	0.125–0.25 mg/kg	PO	Every 12 h	Do not use in: Benzodiazepine hypersensitivity; Start at the lower endpoint; distinct from lower-dose alternatives and titrate to tolerance.
Refractory house soiling	0.1 mg/kg	PO	Every 8–12 h	Do not use in: Benzodiazepine hypersensitivity
Refractory house soiling - fixed alternative	0.125–0.25 mg/animal	PO	Every 8–12 h	Do not use in: Benzodiazepine hypersensitivity
Urine marking	0.05–0.2 mg/kg	PO	Every 12–24 h	Do not use in: Benzodiazepine hypersensitivity
Fears and phobias	0.125–0.25 mg/animal	PO	Every 8–24 h	Do not use in: Benzodiazepine hypersensitivity
Acute anxiety	0.05 mg/kg	PO	Every 8 h	Do not use in: Benzodiazepine hypersensitivity; Alternative is as needed; administer 30–60 minutes before the trigger.

Horses

Use / stage	Dose	Route	Schedule	Instructions
Behavioral anxiety — Loading	0.1 mg/kg	PO	Once	Do not use in: Benzodiazepine hypersensitivity; Follow with the maintenance schedule.
Behavioral anxiety — Maintenance	0.04 mg/kg	PO	Every 12 h	Do not use in: Benzodiazepine hypersensitivity

Indications

Short-term management of canine noise phobia, thunderstorm phobia and other acute panic or situational anxiety responses.
Adjunctive treatment of selected canine anxiety disorders within a behavioral treatment plan.
Treatment of selected feline anxiety disorders.
Selected equine behavioral applications, including anxiety interfering with mare–foal bonding or acceptance of an orphan foal.

Contraindications

Use cautiously during early pregnancy; animal reproductive risk is not established.
Taper after prolonged use to reduce withdrawal.
Benzodiazepine hypersensitivity.
Use cautiously in narrow-angle glaucoma, renal or hepatic disease, and debilitated or geriatric patients.
Behavioral disinhibition may increase aggression; evaluate this risk in aggressive animals.

Interactions

Ketoconazole, itraconazole and chloramphenicol may decrease hepatic metabolism.
Other CNS depressants have additive effects.
Separate antacids by 2 hours.
Fluoxetine, fluvoxamine, cimetidine, erythromycin and isoniazid may increase exposure; rifampin may reduce effect.
Digoxin or tricyclic-antidepressant exposure may increase; assess for toxicity.

Adverse effects

Sedation.
Paradoxical excitement.
Dependence and withdrawal with chronic use.
Increased appetite, transient ataxia and altered feline behavior.
Learning and performance of working animals may be impaired.

Toxicity

Overdose can cause ataxia, agitation, disorientation or CNS depression. Monitor respiration and cardiovascular function. Decontamination depends on airway safety; flumazenil may be considered for clinically important respiratory depression.

Preparations

Preparation	Form	Strength	Route
Alprazolam 0.25 mg tablet	Tablet	0.25 mg / tablet	PO
Alprazolam 0.5 mg tablet	Tablet	0.5 mg / tablet	PO
Alprazolam 1 mg tablet	Tablet	1 mg / tablet	PO
Alprazolam 2 mg tablet	Tablet	2 mg / tablet	PO
Atrest alprazolam 0.25 mg tablet	Tablet	0.25 mg / tablet	PO
Atrest alprazolam 0.5 mg tablet	Tablet	0.5 mg / tablet	PO
Niravam alprazolam 0.25 mg orally disintegrating tablet Rapidly dissolving oral tablet; equal-dose divisions are not established here.	Tablet	0.25 mg / tablet	PO
Niravam alprazolam 0.5 mg orally disintegrating tablet Rapidly dissolving oral tablet; equal-dose divisions are not established here.	Tablet	0.5 mg / tablet	PO
Niravam alprazolam 1 mg orally disintegrating tablet Rapidly dissolving oral tablet; equal-dose divisions are not established here.	Tablet	1 mg / tablet	PO
Niravam alprazolam 2 mg orally disintegrating tablet Rapidly dissolving oral tablet; equal-dose divisions are not established here.	Tablet	2 mg / tablet	PO
Alprazolam 1 mg/mL oral solution	Oral Liquid	1 mg / mL	PO

Monitoring and Administration

Monitor liver enzymes during chronic therapy. Effects may last only 2–3 hours in some dogs; efficacy evidence is largely observational.

Store tightly closed, protected from light, at room temperature. Certain compounded preparations have 60-day stability.

Rapidly dissolving alprazolam tablets can simplify administration to difficult-to-medicate patients.

Handle orally disintegrating tablets with dry hands and protect them from moisture. A 1 mg/mL suspension in equal Ora-Plus and Ora-Sweet or Ora-Sweet SF has 60-day stability at 5°C or 25°C, protected from light.

A canine storm-phobia combination trial used clomipramine 2 mg/kg PO every 12 hours for 3 months, followed by 1 mg/kg every 12 hours for 2 weeks and 0.5 mg/kg every 12 hours for 2 weeks. Alprazolam 0.02 mg/kg PO was given 1 hour before anticipated storms and repeated every 4 hours only as needed. Desensitization and counter-conditioning accompanied medication. This is a studied combination course, not evidence that either drug alone produced the improvement.

During combination treatment, assess sedation, ataxia, paradoxical excitation and behavioral disinhibition. Individualize the regimen to response; the clomipramine taper is separate from any taper required after sustained alprazolam use.