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One selection filters the source overview, clinical facts, reports and dose calculator. Literature references are not species-filtered.
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Source overview
Recorded excerpts for one species. Each dose remains a separate source entry; no regimen is selected.
Choose one species to view its source overview. All-species evidence remains available below.
View full clinical evidence and sources ↓Clinical evidence
Pending clinical review (PROPOSED)— applies to the facts and dose entries in this species selection; individual source records retain their own status.
Indications2
Anorexia associated with CKD/azotemia, CHF, GI disease, hepatic disease, neoplasia; nausea/vomiting incl. chemotherapy-induced; peri-operative inappetence
DogCatExtra-label (EXTRA_LABEL)2 source records · View provenance
- Dog · Plumb's Veterinary Drug Handbook, 7th ed., p. 847–849; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 535–536; Perrin C, Seksel K, Landsberg GM. Drug dosage chart. Vet Clin Small Anim 2014;44:629–632 — Indications table · Not applicable · Extra-label (EXTRA_LABEL) · Pending clinical review (PROPOSED) · Rule-based
Original excerpt: Anorexia associated with CKD/azotemia, CHF, GI disease, hepatic disease, neoplasia; nausea/vomiting incl. chemotherapy-induced; peri-operative inappetence — Extra-label (human drug)
- Cat · Plumb's Veterinary Drug Handbook, 7th ed., p. 847–849; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 535–536; Perrin C, Seksel K, Landsberg GM. Drug dosage chart. Vet Clin Small Anim 2014;44:629–632 — Indications table · Not applicable · Extra-label (EXTRA_LABEL) · Pending clinical review (PROPOSED) · Rule-based
Original excerpt: Anorexia associated with CKD/azotemia, CHF, GI disease, hepatic disease, neoplasia; nausea/vomiting incl. chemotherapy-induced; peri-operative inappetence — Extra-label (human drug)
- Dog · Plumb's Veterinary Drug Handbook, 7th ed., p. 847–849; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 535–536; Perrin C, Seksel K, Landsberg GM. Drug dosage chart. Vet Clin Small Anim 2014;44:629–632 — Indications table · Not applicable · Extra-label (EXTRA_LABEL) · Pending clinical review (PROPOSED) · Rule-based
Dose regimens5
This calculator performs arithmetic only on the sourced dosing field shown for each result — it does not verify the field's accuracy, does not select which field to use for a patient, and does not replace a veterinarian's order. Not for clinical use. Confirm every result against the primary source before dispensing.
Choose one species above to view its dose calculator.
Adverse effects204
Sedation/drowsiness — Main, dose-dependent
Other speciesNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Other species · Plumb's Veterinary Drug Handbook, 7th ed., p. 847–849; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 535–536; Perrin C, Seksel K, Landsberg GM. Drug dosage chart. Vet Clin Small Anim 2014;44:629–632 — Side Effects / Adverse Effects table · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
Vocalization, increased affection — Notable
CatNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Cat · Plumb's Veterinary Drug Handbook, 7th ed., p. 847–849; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 535–536; Perrin C, Seksel K, Landsberg GM. Drug dosage chart. Vet Clin Small Anim 2014;44:629–632 — Side Effects / Adverse Effects table · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
Hypotension (orthostatic), tachycardia — Dose-dependent
Other speciesNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Other species · Plumb's Veterinary Drug Handbook, 7th ed., p. 847–849; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 535–536; Perrin C, Seksel K, Landsberg GM. Drug dosage chart. Vet Clin Small Anim 2014;44:629–632 — Side Effects / Adverse Effects table · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
Blood dyscrasias (rare) — Human signal — caution in leukopenia/neutropenia/thrombocytopenia
Other speciesNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Other species · Plumb's Veterinary Drug Handbook, 7th ed., p. 847–849; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 535–536; Perrin C, Seksel K, Landsberg GM. Drug dosage chart. Vet Clin Small Anim 2014;44:629–632 — Side Effects / Adverse Effects table · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
These are counts of spontaneously reported events, not proven adverse effects, causal relationships, or incidence rates.
Bars compare report counts within each species; they do not show incidence.
More reportsFewer reportsDog
- Death by euthanasia73 reports
- Anorexia68 reports
- Vomiting65 reports
- Lethargy (see also Central nervous system depression in 'Neurological')58 reports
- Elevated alanine aminotransferase (ALT)51 reports
- Decreased appetite47 reports
- Diarrhoea46 reports
- Weight loss45 reports
- Other abnormal test result NOS44 reports
- Elevated serum alkaline phosphatase (SAP)40 reports
- Abnormal ultrasound finding37 reports
- Elevated total bilirubin36 reports
Cat
- Lack of efficacy - NOS260 reports
- Death by euthanasia229 reports
- Vomiting215 reports
- Weight loss176 reports
- Not eating153 reports
- Application site reddening151 reports
- Anorexia150 reports
- Death133 reports
- Lethargy (see also Central nervous system depression in 'Neurological')132 reports
- Lethargy (see also Central nervous system depression in Neurological)132 reports
- Behavioural disorder NOS129 reports
- Diarrhoea118 reports
Monitoring1
Appetite, vomiting episodes, weight; sedation level; behavior (vocalization)
Species not recordedNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Species not recorded · Plumb's Veterinary Drug Handbook, 7th ed., p. 847–849; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 535–536; Perrin C, Seksel K, Landsberg GM. Drug dosage chart. Vet Clin Small Anim 2014;44:629–632 — Monitoring Parameters · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
Contraindications1
MAO inhibitor use within past 14 days (e.g., selegiline) — serotonin syndrome risk
Species not recordedNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Species not recorded · Plumb's Veterinary Drug Handbook, 7th ed., p. 847–849; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 535–536; Perrin C, Seksel K, Landsberg GM. Drug dosage chart. Vet Clin Small Anim 2014;44:629–632 — Contraindications & Warnings table · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
Precautions5
Cardiac/cerebrovascular disease (hypotension); renal or hepatic impairment; diabetes (antidepressants can affect glucose); urinary retention/prostatic hypertrophy/glaucoma/GI obstruction (weak anticholinergic activity)
Species not recordedNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Species not recorded · Plumb's Veterinary Drug Handbook, 7th ed., p. 847–849; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 535–536; Perrin C, Seksel K, Landsberg GM. Drug dosage chart. Vet Clin Small Anim 2014;44:629–632 — Contraindications & Warnings table · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
Cats: ¼ of a 15 mg tablet every 72 hours — the every-3-day interval exists because cats glucuronidate poorly; daily dosing risks accumulation (Quimby PK data, t½ 10–15 h even in healthy cats, longer with CKD).
Species not recordedNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Species not recorded · Plumb's Veterinary Drug Handbook, 7th ed., p. 847–849; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 535–536; Perrin C, Seksel K, Landsberg GM. Drug dosage chart. Vet Clin Small Anim 2014;44:629–632 — Clinical pearl · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
Dosing conflict in the literature: the Perrin 2014 behavioral chart lists 1 mg/cat PO q24h — this daily scheme predates the feline PK work; prefer the Plumb q72h 3.75 mg regimen for cats, especially with renal disease.
Species not recordedNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Species not recorded · Plumb's Veterinary Drug Handbook, 7th ed., p. 847–849; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 535–536; Perrin C, Seksel K, Landsberg GM. Drug dosage chart. Vet Clin Small Anim 2014;44:629–632 — Clinical pearl · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
Appetite stimulation is the desired "side effect" (via H1/5-HT2 antagonism and alpha2 blockade); antiemesis comes from 5-HT3 antagonism — mirtazapine can stack with maropitant/ondansetron for refractory nausea.
Species not recordedNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Species not recorded · Plumb's Veterinary Drug Handbook, 7th ed., p. 847–849; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 535–536; Perrin C, Seksel K, Landsberg GM. Drug dosage chart. Vet Clin Small Anim 2014;44:629–632 — Clinical pearl · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
Do not exceed 30 mg/day for appetite stimulation — effect paradoxically disappears above the ceiling.
Species not recordedNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Species not recorded · Plumb's Veterinary Drug Handbook, 7th ed., p. 847–849; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 535–536; Perrin C, Seksel K, Landsberg GM. Drug dosage chart. Vet Clin Small Anim 2014;44:629–632 — Clinical pearl · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
Interactions5
Tramadol, linezolid — Increased serotonin syndrome risk
Species not recordedNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Species not recorded · Plumb's Veterinary Drug Handbook, 7th ed., p. 847–849; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 535–536; Perrin C, Seksel K, Landsberg GM. Drug dosage chart. Vet Clin Small Anim 2014;44:629–632 — Drug Interactions table · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
Selegiline, amitraz — Serotonin syndrome — considered contraindicated
Species not recordedNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Species not recorded · Plumb's Veterinary Drug Handbook, 7th ed., p. 847–849; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 535–536; Perrin C, Seksel K, Landsberg GM. Drug dosage chart. Vet Clin Small Anim 2014;44:629–632 — Drug Interactions table · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
Fluvoxamine — ↑ mirtazapine levels
Species not recordedNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Species not recorded · Plumb's Veterinary Drug Handbook, 7th ed., p. 847–849; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 535–536; Perrin C, Seksel K, Landsberg GM. Drug dosage chart. Vet Clin Small Anim 2014;44:629–632 — Drug Interactions table · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
Clonidine — Blood pressure increase
Species not recordedNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Species not recorded · Plumb's Veterinary Drug Handbook, 7th ed., p. 847–849; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 535–536; Perrin C, Seksel K, Landsberg GM. Drug dosage chart. Vet Clin Small Anim 2014;44:629–632 — Drug Interactions table · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
Benzodiazepines — Additive motor-skill impairment
Species not recordedNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Species not recorded · Plumb's Veterinary Drug Handbook, 7th ed., p. 847–849; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 535–536; Perrin C, Seksel K, Landsberg GM. Drug dosage chart. Vet Clin Small Anim 2014;44:629–632 — Drug Interactions table · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
Pharmacokinetics5
Bioavailability — ~20% (dog, rat); ~50% (human)
Other speciesNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Other species · Plumb's Veterinary Drug Handbook, 7th ed., p. 847–849; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 535–536; Perrin C, Seksel K, Landsberg GM. Drug dosage chart. Vet Clin Small Anim 2014;44:629–632 — Pharmacokinetics table · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
Protein binding — ~70–72% (dog); ~85% (human)
Other speciesNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Other species · Plumb's Veterinary Drug Handbook, 7th ed., p. 847–849; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 535–536; Perrin C, Seksel K, Landsberg GM. Drug dosage chart. Vet Clin Small Anim 2014;44:629–632 — Pharmacokinetics table · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
Half-life — 10.2–15.4 h (cat, 1.88–3.75 mg doses); 20–40 h (human)
Other speciesNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Other species · Plumb's Veterinary Drug Handbook, 7th ed., p. 847–849; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 535–536; Perrin C, Seksel K, Landsberg GM. Drug dosage chart. Vet Clin Small Anim 2014;44:629–632 — Pharmacokinetics table · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
Metabolism — CYP2D6/1A2/3A4 + glucuronidation
CatNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Cat · Plumb's Veterinary Drug Handbook, 7th ed., p. 847–849; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 535–536; Perrin C, Seksel K, Landsberg GM. Drug dosage chart. Vet Clin Small Anim 2014;44:629–632 — Pharmacokinetics table · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
Elimination — Urine 75%, feces 15% (human)
Other speciesNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Other species · Plumb's Veterinary Drug Handbook, 7th ed., p. 847–849; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 535–536; Perrin C, Seksel K, Landsberg GM. Drug dosage chart. Vet Clin Small Anim 2014;44:629–632 — Pharmacokinetics table · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
Pregnancy / lactation considerations1
Human FDA category C; no teratogenicity in rats/rabbits/dogs, but post-implantation losses and pup deaths increased; caution in nursing (excreted in small amounts in milk).
Species not recordedNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Species not recorded · Plumb's Veterinary Drug Handbook, 7th ed., p. 847–849; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 535–536; Perrin C, Seksel K, Landsberg GM. Drug dosage chart. Vet Clin Small Anim 2014;44:629–632 — Pregnancy & Lactation · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
Literature references13
References are linked to this drug. Species applicability is not recorded here, so the species filter does not narrow this list. Imported dates do not retain their original precision; confirm dates in the original citation.
- Overcoming mirtazapine's therapeutic limitations in veterinary practice: Development of a taste - masked orally disintegrating tablet with microsphere-based controlled release.
Study summary not available in the imported record. Open the original citation to review the study.
- Owner's Perspective About the Use of Mirtazapine Transdermal Ointment in Cats-A Survey-Based Study.
Study summary not available in the imported record. Open the original citation to review the study.
- Plasma concentrations of mirtazapine are significantly different between sampling sites after oral administration in alpacas.
Study summary not available in the imported record. Open the original citation to review the study.
- Evaluation of the Short-Term Effects of Mirtazapine on Appetite Stimulants in Dogs: A Retrospective Study and a Placebo-Controlled Trial.
Study summary not available in the imported record. Open the original citation to review the study.
- Preliminary Pharmacokinetics and Appetite Stimulant Efficacy of Oral Mirtazapine in Guinea Pigs (Cavia porcellus).
Study summary not available in the imported record. Open the original citation to review the study.
Sources: PubMed, National Library of Medicine; openFDA, U.S. Food and Drug Administration; Perrin C, Seksel K, Landsberg GM. Appendix: Drug Dosage Chart. Vet Clin Small Anim 2014;44:629-632.; Plumb DC. Plumb's Veterinary Drug Handbook. 7th ed. PharmaVet Inc; 2011.
Owner information handout
Plain-language medication information to review with the owner. Open the handout to print it or download a PDF.
Available products
Products listed in the Health Canada Drug Product Database for this active ingredient. A listing does not establish that a product is authorized for the clinical uses described on this page.