Gemfibrozil
5-(2,5-dimethylphenoxy)-2,2-dimethylpentanoic acid (Fibric acid derivative)
Also known as: Lopid · CI-719 · gemfibrozilo · gemfibrozilium
Reviewed by the VetSheet Veterinary TeamUpdated Apr 5, 2026Evidence-based veterinary reference
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Dosing by species
🌎 NA — North America🌍 EU — Europe
Dogs
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| Hypertriglyceridemia (not controlled with diet alone) | 150 mg-300 mg (total dose) | PO | q12h | — | 🌎 NA |
| Hypertriglyceridemia (not controlled with diet alone) | 200 mg (total dose) | PO | once daily | — | 🌎 NA |
Cats
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| Hypertriglyceridemia (not controlled with diet alone) | 7.5-10 mg/kg | PO | q12h | — | 🌎 NA |
| Hypertriglyceridemia (not controlled with diet alone) | 10 mg/kg | PO | q12h | — | 🌎 NA |
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Overview
Gemfibrozil is an oral antihyperlipidemic agent belonging to the fibrate class.
Clinical Pearl: While primarily used in human medicine, it is utilized off-label in veterinary medicine for severe hypertriglyceridemia (often >500 mg/dL) in dogs and cats, particularly when dietary management (ultra-low-fat diets) fails. Miniature Schnauzers are a classic breed prone to primary hyperlipidemia that might require this therapy.
Key features include:
- Used as an adjunctive therapy alongside strict dietary fat restriction.
- May reduce influenza-related mortality (noted in murine models) and is being investigated as an adjunctive treatment for severe influenza.
- Clinical experience in veterinary medicine is highly limited, and efficacy/safety profiles are not fully established.
Mechanism of action
Gemfibrozil acts primarily as an agonist for the Peroxisome Proliferator-Activated Receptor-alpha (PPAR-α).
- PPAR-α activation → alters transcription of genes involved in lipid metabolism.
- Increases lipoprotein lipase (LPL) activity → enhances clearance of triglyceride-rich lipoproteins.
- Inhibits lipolysis in adipose tissue → reduces hepatic uptake of plasma free fatty acids → decreases hepatic production of triglycerides.
- Inhibits the synthesis of apolipoprotein B (the primary carrier protein for VLDL) → reduces VLDL production and the incorporation of long-chain fatty acids into triglycerides.
Safety & warnings
Contraindications
- Severe hepatic dysfunction
- Severe renal dysfunction
- Known hypersensitivity to gemfibrozil
Adverse effects
- Abdominal pain
- Vomiting
- Diarrhea
- Abnormal liver function tests
- Dyspepsia (human)
- CNS effects: headache, somnolence, dizziness (human)
- Myositis (human)
- Bone marrow depression (rare, human)
Precautions
Use with extreme caution in dogs or cats as very limited safety data is available for this medication.
Pregnancy Warning: In humans, it is FDA Category C. Animal studies (rats/rabbits) have shown decreased fertility rates, decreased litter sizes, and skeletal abnormalities at doses near the human dose. Safe use during nursing cannot be assured.
Drug interactions
May possibly increase triglyceride concentrations
May possibly increase triglyceride concentrations
May possibly increase triglyceride concentrations
May reduce effectiveness of gemfibrozil
Gemfibrozil may potentiate anticoagulant effects
Monitoring
- Plasma triglycerides (realistic goal for therapy is 400 mg/dL or less)
- Baseline and periodic CBC
- Baseline and periodic liver function tests
- Adverse clinical effects (GI upset, behavior changes)
- Client adherence to prescribed diet and dosing schedule
Pharmacokinetics
Absorption
In humans, rapidly and completely absorbed from the GI tract. Rate and extent of absorption are greatest when administered 30 minutes before a meal. (No veterinary data available).
Distribution
Highly bound to plasma protein. Highest concentrations are found in the liver and kidneys.
Metabolism
Hepatic metabolism; 4 major metabolites are formed in humans.
Elimination
Primarily excreted in the urine.
Overdose
Limited veterinary information is available. The reported LD50 (oral) in rats is 1414 mg/kg.
- Treatment: Consider gut-emptying protocols for recent large oral ingestions and provide supportive care as required.
- Monitoring: Monitor for dehydration and electrolyte imbalance if vomiting and/or diarrhea is severe or persists. Monitor liver function tests.
Available products
Formulations
- Oral tablets
- Oral capsules
Human-labeled
- Gemfibrozil Oral Tablets: 600 mg (Lopid®, generic)
- Gemfibrozil Oral Capsules: 300 mg (Available in Canada)
Regulatory status
No regulatory data for: 🇺🇸 US · 🇪🇺 EU · 🇬🇧 UK · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
Storage & stability
Store tablets or capsules below 30°C (86°F) in tight containers.
Client information
Gemfibrozil is used to help lower dangerously high triglyceride (fat) levels in your pet's blood.
Important: This medication is an addition to a strict low-fat diet, not a replacement for it. If your pet eats high-fat treats or food, the medication will likely not work.
- Administration: For best absorption, try to give this medication about 30 minutes before a meal.
- Investigational Use: This drug is FDA-approved for humans, but its use in dogs and cats is considered 'off-label' or investigational.
- What to Watch For: Contact your veterinarian if you notice any changes in behavior, decreased activity, stomach upset (vomiting, diarrhea, loss of appetite), or yellowing of the eyes/gums (jaundice).
VetSheet drug reference is intended for licensed veterinary professionals as a clinical decision-support aid, not a substitute for professional judgement or the manufacturer’s current label.