Piroxicam
Piroxicam is an NSAID used selectively for pain and as an adjunct in some animal oncology protocols. Elimination is prolonged in dogs.
Group
Oxicam nonsteroidal anti-inflammatory drug
Mechanism of Action
Inhibits cyclooxygenase and prostaglandin synthesis; antitumor effects have also been described.
Dose Rates
Dogs
| Use / stage | Dose | Route | Schedule | Instructions |
|---|---|---|---|---|
| Musculoskeletal pain | 0.3 mg/kg | PO | Every 48 h | |
| Adjunctive cancer treatment — Initial | 0.3 mg/kg | PO | Every 24 h | Initial daily stage; then transition to the separately listed 48-hour schedule according to response and tolerance. |
| Adjunctive cancer treatment — Maintenance | 0.3 mg/kg | PO | Every 48 h | |
| Cancer pain | 0.3 mg/kg | PO | Every 24–48 h | |
| Lymphoplasmacytic rhinitis adjunct | 0.3 mg/kg | PO | Every 24 h | Described with doxycycline 3–5 mg/kg PO q12h or azithromycin 5 mg/kg PO q24h. At 2 weeks, if improved, reduce doxycycline to daily or azithromycin to twice weekly; piroxicam remains daily. Courses may last at least 6 months; reassess benefit and toxicity. |
Cats
| Use / stage | Dose | Route | Schedule | Instructions |
|---|---|---|---|---|
| Selected pain or cancer treatment | 0.3 mg/kg | PO | Every 24 h | Assess gastrointestinal and renal tolerance; not a general substitute for an approved feline NSAID. |
| Alternative fixed feline regimen | 1 mg/animal | PO | Every 24 h | Up to 7 days; Alternative commonly listed total amount; do not administer in addition to the mg/kg regimen. For the pain course, maximum 7 days; not an unlimited oncology prescription. |
| Urothelial carcinoma adjunct | 0.3 mg/kg | PO | Every 24–72 h | Empirical oncology regimen; monitor GI signs, hematocrit and renal function. Alternatives are separate courses, not concurrent dosing. |
| Alternative neoplasia adjunct | 0.3 mg/kg | PO | Every 24–48 h | Reported neoplasia course; analgesic effectiveness cannot be assumed from the cancer literature. |
| Cancer pain | 0.3 mg/kg | PO | Every 24–48 h | Up to 7 days |
| Chronic idiopathic rhinosinusitis adjunct | 0.3 mg/kg | PO | Every 24–48 h |
Horses
| Use / stage | Dose | Route | Schedule | Instructions |
|---|---|---|---|---|
| Experimental single exposure | Reference only | PO | A single 0.2 mg/kg oral exposure was reported without adverse effects; evidence is insufficient to recommend a treatment regimen. | |
| Squamous-cell carcinoma case reports | Reference only | PO | Two reports used 80 mg total orally once daily after or during tumor management. One horse developed colic and was reduced to every other or every third day. These patient-specific totals are not universal equine doses. |
Rabbits
| Use / stage | Dose | Route | Schedule | Instructions |
|---|---|---|---|---|
| Fracture-associated limb swelling | 0.1–0.2 mg/kg | PO | Every 8 h | Up to 21 days; Historical regimen; assess GI and renal risk. |
Indications
- Selected musculoskeletal pain
- Adjunctive treatment of selected tumors, including urothelial carcinoma
Contraindications
- Gastrointestinal ulceration
- Pregnancy
- Clinically significant dehydration or renal compromise
Interactions
- Do not combine with other NSAIDs or corticosteroids.
- Cisplatin and other nephrotoxic drugs increase renal risk.
- May interfere with diuretics and ACE inhibitors.
- Anticoagulants increase bleeding risk; methotrexate toxicity may be potentiated.
- Bisphosphonates may add GI ulcer risk.
Adverse effects
- Vomiting or gastrointestinal ulceration
- Gastrointestinal bleeding
- Renal injury
- Rare severe cutaneous reactions
Toxicity
Overdose can cause prolonged gastrointestinal and renal injury. Stop treatment and provide appropriate monitoring and support.
Preparations
| Preparation | Form | Strength | Route |
|---|---|---|---|
| Piroxicam capsules 10 mg May require professional reformulation for accurate small-animal administration; no assumed compounded stability. | Capsule | 10 mg / capsule | PO |
| Piroxicam capsules 20 mg | Capsule | 20 mg / capsule | PO |
Monitoring and Administration
Monitor appetite, vomiting, melena, CBC when bleeding is suspected, and renal function.
Dog cancer regimens may start daily and move to every 48 hours to improve tolerability; do not combine stages as concurrent doses.
The human capsule strength may be unsuitable for small animals. Compounded products need an established stability period; protect from light.
Selected canine oncology combinations retain their own protocols: piroxicam 0.3 mg/kg PO daily with alternating 3-week etoposide (50 mg/m² daily) and cyclophosphamide (12.5–25 mg/m² daily) courses for stage-II splenic hemangiosarcoma; or with mitoxantrone 5 mg/m² IV every 3 weeks for 4 treatments after urothelial tumor laser ablation. These are complex oncology plans, not simple calculator regimens.
A separate metronomic soft-tissue sarcoma course uses piroxicam 0.3 mg/kg PO daily with cyclophosphamide 10 mg/m² PO daily; alternate-day dosing was used for unacceptable adverse effects. Do not confuse mg/m² with mg/kg.
Give with food to reduce GI upset where appropriate. Some poorly tolerant dogs have been given misoprostol 3 mcg/kg PO q8h; stop piroxicam for significant ulceration or bleeding. Monitor CBC/hematocrit, liver and renal function with chronic therapy.
Piroxicam may interfere with glucose oxidase/peroxidase assays using ABTS. Product-specific compounded stability must be verified; one formulation’s 10-day period does not validate all oral mixtures.