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One selection filters the source overview, clinical facts, reports and dose calculator. Literature references are not species-filtered.
Choose one species for its overview and dose calculator, or all species to browse the full evidence.
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)Rule-based (RULE_BASED)— applies to the facts and dose entries in this species selection; individual source records retain their own status.
Indications2
Peri-op/CRI analgesia (injectable); post-op pain control up to 4 days (Recuvyra, dogs) or via patch
DogCatExtra-label (EXTRA_LABEL)2 source records · View provenance
- Dog · Plumb's Veterinary Drug Handbook, 7th ed., p. 513–516; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 318–321 — Indications table · Not applicable · Extra-label (EXTRA_LABEL) · Pending clinical review (PROPOSED) · Rule-based
Original excerpt: Peri-op/CRI analgesia (injectable); post-op pain control up to 4 days (Recuvyra, dogs) or via patch — Extra-label (injectable/patch); Recuvyra authorized in dogs
- Cat · Plumb's Veterinary Drug Handbook, 7th ed., p. 513–516; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 318–321 — Indications table · Not applicable · Extra-label (EXTRA_LABEL) · Pending clinical review (PROPOSED) · Rule-based
Original excerpt: Peri-op/CRI analgesia (injectable); post-op pain control up to 4 days (Recuvyra, dogs) or via patch — Extra-label (injectable/patch); Recuvyra authorized in dogs
- Dog · Plumb's Veterinary Drug Handbook, 7th ed., p. 513–516; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 318–321 — Indications table · Not applicable · Extra-label (EXTRA_LABEL) · Pending clinical review (PROPOSED) · Rule-based
Dose regimens7
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 effects205
Respiratory/CNS/circulatory depression (bradycardia) — Dose-related
DogCatNot applicable (NOT_APPLICABLE)2 source records · View provenance
- Dog · Plumb's Veterinary Drug Handbook, 7th ed., p. 513–516; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 318–321 — Side Effects / Adverse Effects table · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
- Cat · Plumb's Veterinary Drug Handbook, 7th ed., p. 513–516; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 318–321 — Side Effects / Adverse Effects table · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
Rash at patch site, urine retention, constipation, dysphoria/agitation — Reported
DogCatNot applicable (NOT_APPLICABLE)2 source records · View provenance
- Dog · Plumb's Veterinary Drug Handbook, 7th ed., p. 513–516; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 318–321 — Side Effects / Adverse Effects table · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
- Cat · Plumb's Veterinary Drug Handbook, 7th ed., p. 513–516; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 318–321 — Side Effects / Adverse Effects table · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
Excitement, restlessness, tachycardia — Common at analgesic doses
HorseNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Horse · Plumb's Veterinary Drug Handbook, 7th ed., p. 513–516; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 318–321 — 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
- Anorexia150 reports
- Vocalisation111 reports
- Vomiting89 reports
- Hypothermia81 reports
- Lethargy (see also Central nervous system depression in 'Neurological')80 reports
- Death by euthanasia79 reports
- Sedation77 reports
- Not eating67 reports
- Diarrhoea60 reports
- Death59 reports
- Inappetence58 reports
- Lack of efficacy - NOS57 reports
Cat
- Not eating15 reports
- Death by euthanasia14 reports
- Hypotension14 reports
- Fever12 reports
- Hyperglycaemia12 reports
- Death11 reports
- Other abnormal test result NOS11 reports
- Dehydration9 reports
- Weight loss9 reports
- Anaemia NOS8 reports
- Tachypnoea8 reports
- Anorexia7 reports
Monitoring1
Respiratory rate/depth (pulse oximetry), heart rate, analgesic efficacy, sedation/excitement level
Species not recordedNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Species not recorded · Plumb's Veterinary Drug Handbook, 7th ed., p. 513–516; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 318–321 — Monitoring Parameters · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
Contraindications1
Known hypersensitivity
Species not recordedNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Species not recorded · Plumb's Veterinary Drug Handbook, 7th ed., p. 513–516; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 318–321 — Contraindications & Warnings table · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
Precautions5
Geriatric/debilitated/pre-existing respiratory disease; febrile patients (↑ absorption from patch); do not expose patch to external heat sources (fatal over-absorption reported)
Species not recordedNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Species not recorded · Plumb's Veterinary Drug Handbook, 7th ed., p. 513–516; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 318–321 — Contraindications & Warnings table · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
Dosing is in micrograms/kg in most references — always double-check mcg vs mg to avoid catastrophic 1000x errors.
Species not recordedNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Species not recorded · Plumb's Veterinary Drug Handbook, 7th ed., p. 513–516; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 318–321 — Clinical pearl · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
DO NOT CUT transdermal patches — alters the drug-release membrane and can cause dangerous rapid release; consult a pharmacist if a partial dose is needed.
Species not recordedNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Species not recorded · Plumb's Veterinary Drug Handbook, 7th ed., p. 513–516; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 318–321 — Clinical pearl · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
Patch absorption is highly interpatient-variable — always have injectable rescue analgesia available when relying on a patch as primary analgesic.
Species not recordedNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Species not recorded · Plumb's Veterinary Drug Handbook, 7th ed., p. 513–516; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 318–321 — Clinical pearl · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
Never apply external heat (heating pads) over a fentanyl patch — fatal overdoses have resulted from increased absorption.
Species not recordedNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Species not recorded · Plumb's Veterinary Drug Handbook, 7th ed., p. 513–516; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 318–321 — Clinical pearl · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
Interactions5
Azole antifungals, macrolides (erythromycin, clarithromycin) — Inhibit fentanyl metabolism → ↑ levels
Species not recordedNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Species not recorded · Plumb's Veterinary Drug Handbook, 7th ed., p. 513–516; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 318–321 — Drug Interactions table · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
MAO inhibitors (amitraz, selegiline) — Severe, unpredictable potentiation — avoid
Species not recordedNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Species not recorded · Plumb's Veterinary Drug Handbook, 7th ed., p. 513–516; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 318–321 — Drug Interactions table · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
Phenobarbital, phenytoin, rifampin — ↑ fentanyl metabolism (↓ levels)
Species not recordedNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Species not recorded · Plumb's Veterinary Drug Handbook, 7th ed., p. 513–516; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 318–321 — Drug Interactions table · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
Tricyclic antidepressants — Fentanyl may exacerbate TCA effects
Species not recordedNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Species not recorded · Plumb's Veterinary Drug Handbook, 7th ed., p. 513–516; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 318–321 — Drug Interactions table · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
Other CNS depressants — Additive depression
Species not recordedNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Species not recorded · Plumb's Veterinary Drug Handbook, 7th ed., p. 513–516; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 318–321 — Drug Interactions table · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
Pharmacokinetics5
Potency — ~80–100x morphine
Other speciesNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Other species · Plumb's Veterinary Drug Handbook, 7th ed., p. 513–516; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 318–321 — Pharmacokinetics table · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
Protein binding — ~15.6% (dog) — low
Other speciesNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Other species · Plumb's Veterinary Drug Handbook, 7th ed., p. 513–516; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 318–321 — Pharmacokinetics table · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
Half-life — ~2–6h IV (dog); ~2.5h (cat)
Other speciesNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Other species · Plumb's Veterinary Drug Handbook, 7th ed., p. 513–516; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 318–321 — Pharmacokinetics table · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
Metabolism — Hepatic; clearance ≈ hepatic blood flow
Species not recordedNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Species not recorded · Plumb's Veterinary Drug Handbook, 7th ed., p. 513–516; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 318–321 — Pharmacokinetics table · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
Elimination — Renal (metabolites)
Species not recordedNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Species not recorded · Plumb's Veterinary Drug Handbook, 7th ed., p. 513–516; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 318–321 — Pharmacokinetics table · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
Pregnancy / lactation considerations1
Safety not established. Human FDA category C. Most opioids cross into milk at levels not clinically significant short-term.
Species not recordedNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Species not recorded · Plumb's Veterinary Drug Handbook, 7th ed., p. 513–516; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 318–321 — Pregnancy & Lactation · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
Literature references15
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.
- Development of a nalmefene formulation suitable for a community-use auto-injector.
Study summary not available in the imported record. Open the original citation to review the study.
- Xylazine test strip utilization among pregnant and postpartum women with opioid use disorder: A pilot study.
Study summary not available in the imported record. Open the original citation to review the study.
- Xylazine reduces methamphetamine-induced hyperlocomotion in rats through κ-opioid and α2-adrenoceptor mechanisms.
Study summary not available in the imported record. Open the original citation to review the study.
- Respiratory depressant interactions of fentanyl and xylazine and their reversal by naloxone and yohimbine in mice.
Study summary not available in the imported record. Open the original citation to review the study.
- Ultrasound-guided bilateral quadratus lumborum block in dogs undergoing abdominal surgery: A retrospective study.
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; 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.