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PetDosageChart

Prozac (Fluoxetine) Dosage for Dogs

Selective serotonin reuptake inhibitor (SSRI) ⏱ Onset: 4-6 weeks for full behavioral effect ⏳ Duration: 24 hours per dose

This dosage information is for educational purposes only. Always consult your veterinarian before giving any medication to your pet. Dosages may vary based on your pet's health conditions, other medications, and individual factors.

Content reviewed by licensed veterinarians. This information is sourced from veterinary drug references including Plumb's Veterinary Drug Handbook and the Merck Veterinary Manual.

Dosage Calculator

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Prozac Dosage Chart for Dogs by Weight

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Weight Low Dose Standard Dose Max Dose Frequency
5 lbs (2.3 kg) 2.5mg 3.5mg 4.5mg Once daily
10 lbs (4.5 kg) 4.5mg 7mg 9mg (10mg tablet) Once daily
15 lbs (6.8 kg) 7mg 10mg (10mg tablet) 13.5mg Once daily
20 lbs (9.1 kg) 9mg (10mg tablet) 13.5mg 18mg (2 × 10mg) Once daily
25 lbs (11.3 kg) 11.5mg (10mg tablet) 17mg 22.5mg Once daily
30 lbs (13.6 kg) 13.5mg 20.5mg (2 × 10mg) 27mg Once daily
40 lbs (18.1 kg) 18mg (2 × 10mg) 27mg 36mg Once daily
50 lbs (22.7 kg) 22.5mg 34mg 45.5mg Once daily
60 lbs (27.2 kg) 27mg 41mg (4 × 10mg) 54.5mg Once daily
70 lbs (31.7 kg) 31.5mg (3 × 10mg) 47.5mg (5 × 10mg) 63.5mg Once daily
80 lbs (36.3 kg) 36.5mg 54.5mg 72.5mg Once daily
90 lbs (40.8 kg) 41mg (4 × 10mg) 61mg (6 × 10mg) 81.5mg (8 × 10mg) Once daily
100 lbs (45.4 kg) 45.5mg 68mg (7 × 10mg) 91mg (9 × 10mg) Once daily
120 lbs (54.4 kg) 54.5mg 81.5mg (8 × 10mg) 109mg (11 × 10mg) Once daily
150 lbs (68 kg) 68mg (7 × 10mg) 102mg (10 × 10mg) 136mg Once daily

What is Prozac (Fluoxetine) used for in dogs?

Separation anxiety Compulsive behaviors Fear-based aggression Thunderstorm and noise phobias

How to give Prozac to your dog

Give fluoxetine once daily by mouth, with or without food, though giving with food may reduce stomach upset. Administer at the same time each day for consistent blood levels. Tablets can be hidden in a small treat or pill pocket. Do not crush capsules. Allow 4-6 weeks to assess effectiveness before requesting a dose change.

Available Forms

Tablet, Capsule, Oral liquid

Give with Food?

Yes — give with food

Side effects of Prozac in dogs

Common side effects

Decreased appetite
Lethargy or sedation
GI upset (vomiting, diarrhea)
Restlessness or agitation during first week

Serious side effects

  • Serotonin syndrome (tremors, hyperthermia, agitation)
  • Seizures
  • Severe aggression changes
  • Liver enzyme elevation

When to call the vet

Call your vet immediately if your dog shows any of these signs:

  • Tremors, rapid breathing, or hyperthermia (signs of serotonin syndrome)
  • Seizure activity
  • Severe or sudden aggression changes
  • Persistent vomiting or complete refusal to eat for more than 48 hours
  • Significant lethargy or inability to rouse

Related Medications for Dogs

Serotonin antagonist and reuptake inhibitor (SARI)

Desyrel

Trazodone

For anxiety

View dosage chart
ACE inhibitor (angiotensin-converting enzyme inhibitor)

Vasotec

Enalapril

For Congestive heart failure

View dosage chart
Janus kinase (JAK) inhibitor

Apoquel

Oclacitinib

For atopic dermatitis

View dosage chart
Proton pump inhibitor

Prilosec

Omeprazole

For Stomach ulcers

View dosage chart

Sources & References

The dosage information on this page is compiled from the following veterinary and pharmaceutical references:

  • Plumb's Veterinary Drug Handbook — the standard veterinary pharmacology reference used by veterinarians worldwide.
  • Merck Veterinary Manual — a trusted, peer-reviewed resource for veterinary professionals and pet owners.
  • DailyMed (FDA Drug Labels) — official FDA-approved drug labeling and prescribing information for Fluoxetine.

Frequently Asked Questions

How long does fluoxetine take to work in dogs?
Fluoxetine typically takes 4-6 weeks to reach full therapeutic effect in dogs. Some improvement may be noticed within 1-2 weeks, but the full behavioral benefits require consistent daily dosing over several weeks. Do not discontinue early because you see no immediate results.
Can I stop fluoxetine for my dog suddenly?
No. Abrupt discontinuation can cause withdrawal symptoms including irritability, GI upset, and worsening anxiety. Fluoxetine should be tapered gradually over 2-4 weeks under veterinary guidance to avoid rebound behavioral problems.
Does fluoxetine make dogs sleepy?
Some dogs experience mild lethargy or sedation, especially during the first 1-2 weeks. This usually resolves as the body adjusts. If sedation is severe or persistent, contact your veterinarian for a dose adjustment.
Is fluoxetine the same as Prozac for dogs?
Yes, fluoxetine is the generic name for Prozac. Reconcile is the FDA-approved veterinary brand of fluoxetine specifically formulated for dogs. Human generic fluoxetine is also commonly prescribed by veterinarians at appropriate canine doses.
Can fluoxetine be used with behavior training for dogs?
Absolutely. Fluoxetine works best when combined with behavior modification training. The medication reduces the baseline anxiety level so the dog can learn more effectively. It is not intended as a standalone solution but as part of a comprehensive behavioral treatment plan.

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