Drug Monograph
Full clinical overview, indications, dosage references & safety notes.
Available forms3 forms · 5 strengths documentedShow all ↓
Oral tablets 6 mg Tolfedine®Oral tablets 20 mg Tolfedine®Oral tablets 60 mg Tolfedine®
Oral suspension 20 mg/mL Tolfedine®
Injectable solution 40 mg/mL Tolfedine®
Overview
Tolfenamic acid (Tolfedine®) is a nonsteroidal anti-inflammatory drug (NSAID) used in dogs and cats for the alleviation of pain, inflammation, and fever. In dogs, it is also used in the management of chronic locomotor disease. Under its UK authorization the injection covers dogs for post-operative pain and inflammation; it is preferably not given to a cat undergoing general anesthesia until the cat has fully recovered.
Tolfenamic acid should be used cautiously in patients with hepatic or renal disease. In cats, the longer elimination half-life and narrower therapeutic index require careful dose measurement and adherence to the recommended dosage regimen.
Mechanism of Action (MOA): Tolfenamic acid inhibits cyclo-oxygenase (COX), although its selectivity for COX-2 over COX-1 is uncertain. COX inhibition reduces the production of prostaglandins involved in inflammation. It has also been reported to exert a direct antagonistic effect on prostaglandin receptors.
Indications
Tolfenamic acid is used in dogs and cats for the management of pain, inflammation, and fever associated with a variety of clinical conditions.
- Pain and inflammation (dogs and cats): Alleviation of inflammatory conditions and associated pain.
- Chronic locomotor disease (dogs): Management of chronic musculoskeletal disorders.
- Fever (dogs and cats): Management of pyrexia.
- Upper respiratory disease (cats): Given as an adjunct alongside antimicrobial therapy.
Dosage (Reference)
Dog
In dogs, tolfenamic acid is used for the management of pain, inflammation, fever, and chronic locomotor disease. Treatment is initiated with a single injection on the first day, followed by oral therapy when indicated.
| Clinical use | Route | Dose | Frequency | Notes |
|---|---|---|---|---|
| Pain, inflammation, or fever | IM / SC | 4 mg/kg | Once | May be repeated once after 24 hours. |
| Pain, inflammation, chronic locomotor disease, or fever | PO | 4 mg/kg | Once daily for 3 days | Treatment begins with a single injection on Day 1. |
| Long-term oral management (dogs) | PO | 4 mg/kg | Once daily | The 3-day oral regimen may be repeated once weekly: 3 days of medication followed by 4 days without medication. |
- Injectable doses may be repeated once after 24 hours if required.
- For chronic therapy, the oral regimen may be repeated weekly: 3 treatment days followed by 4 rest days.
Cat
In cats, tolfenamic acid is used for the management of pain, inflammation, and fever. Treatment starts with a single injection on the first day, followed by a short oral course. Unlike dogs, repeated weekly treatment is not recommended.
| Clinical use | Route | Dose | Frequency | Notes |
|---|---|---|---|---|
| Pain, inflammation, or fever | SC | 4 mg/kg | Once | May be repeated once after 24 hours. Do not administer IM. |
| Pain, inflammation, or fever | PO | 4 mg/kg | Once daily for 3 days | Treatment begins with a single injection on Day 1. |
| Upper respiratory disease (adjunct) or febrile syndrome | SC or PO | 4 mg/kg | Once daily | Extra-label; give for 3 to 5 days. The injection’s own authorization is a single dose repeated once after 24 hours if required, so a repeated subcutaneous course is outside it. Give the oral dose with food, and give it alongside antimicrobial therapy – this is an adjunct, not a treatment for the infection. |
- Treatment starts with a single injection on Day 1.
- Injectable doses may be repeated once after 24 hours if required.
- Repeated weekly oral treatment is not recommended in cats.
- Because cats have a longer elimination half-life and a narrower therapeutic index, the dose should be measured accurately.
Warnings & Precautions
Tolfenamic acid should be used cautiously in patients at increased risk of NSAID-associated adverse effects. Careful patient selection and accurate dosing are particularly important in cats.
- Hepatic disease: The authorized product labels list hepatic disease as a contraindication rather than a caution.
- Renal disease: Use cautiously in patients with renal disease and during the perioperative period, as renal perfusion may be adversely affected during episodes of hypotension.
- Dehydration or hypotension: Do not use in dehydrated, hypovolaemic, or hypotensive patients.
- Gastrointestinal or coagulation disorders: Contraindicated in patients with gastrointestinal disease or blood clotting disorders, where there is evidence of a blood dyscrasia, and in animals hypersensitive to tolfenamic acid or to another drug of its class such as meclofenamic acid.
- Pregnancy and young animals: Do not use in pregnant animals or in animals younger than 6 weeks of age. Use in aged animals may also involve additional risk; such patients may require a reduced dosage and careful clinical management.
- Cats: Because cats have a longer elimination half-life and a narrower therapeutic index, do not exceed the recommended dose. Use a 1 mL graduated syringe to ensure accurate dose measurement.
- Route restriction in cats: Do not administer intramuscularly.
Drug Interactions
Most clinically important interactions with tolfenamic acid are related to an increased risk of gastrointestinal or renal toxicity when administered with other medications affecting these systems.
- Other NSAIDs: Do not administer concurrently or within 24 hours of another NSAID because of the increased risk of adverse effects.
- Glucocorticoids: Do not administer concurrently or within 24 hours of glucocorticoid therapy due to an increased risk of gastrointestinal toxicity.
- Nephrotoxic drugs (e.g., aminoglycosides): Concurrent administration is not recommended because of the increased risk of renal toxicity.
- Highly protein-bound drugs (e.g., warfarin): Tolfenamic acid can displace other highly protein-bound drugs, such as warfarin, from plasma protein. Monitor closely if the two are used together.
- Methotrexate: Serious toxicity has occurred when NSAIDs have been given together with methotrexate; use the combination with extreme caution.
- Digoxin: NSAIDs may increase serum levels.
- Furosemide: NSAIDs may reduce its saluretic and diuretic effects and may increase the risk of nephrotoxicity.
Side Effects & Overdose
Side Effects
As with other NSAIDs, adverse effects are primarily gastrointestinal. Most reactions are mild and resolve after discontinuation of therapy.
- Gastrointestinal effects: Vomiting, diarrhea, and other gastrointestinal signs may occur in both dogs and cats.Stop treatment immediately if gastrointestinal bleeding is suspected.
- Persistent GI signs: If gastrointestinal adverse effects persist for more than 1–2 days, discontinue treatment.
- Cardiac effects: NSAIDs have been associated with a small risk of precipitating cardiac failure in humans; whether this occurs in animals is unknown. Both authorized labels contraindicate this drug in an animal with cardiac disease.
- Bleeding and surgery: Tolfenamic acid has significant antithromboxane activity and affects platelet function, and for that reason is not recommended before surgery.
Overdose
Overdose would be expected to increase the risk and severity of NSAID-associated adverse effects.
- Management: Treatment is symptomatic. Empty the gut after an oral ingestion, give supportive care, use intravenous diazepam to control seizures, monitor for gastrointestinal bleeding, and monitor electrolyte and fluid balance, managing renal failure by established guidelines.
Key Notes
Practical clinical points that help optimize the safe and effective use of tolfenamic acid in dogs and cats:
- Wash-out period: Allow a 3–5 day wash-out period before starting another NSAID after discontinuing tolfenamic acid.
- Emerging use: In vitro studies and canine tumor cell lines suggest tolfenamic acid may have anticancer activity against some tumor types, but its clinical significance has not been established.
- Administration: Give the oral forms with food.
- Monitoring: In dogs, treatment continuing beyond 3 months should be under regular veterinary supervision.
