Aminocaproic Acid — Veterinary Vademecum Drug Reference

Dosage & Administration Guidelines

Species	Route	Dose	Frequency	Duration & Clinical Notes
Dog	PO	50-100 mg/kg loading dose, then 25-50 mg/kg q8h	q8h	Duration: Variable; typically 3-7 days or as needed Notes: For severe bleeding, IV administration may be preferred initially. Adjust dose in renal impairment.
Dog	IV	50-100 mg/kg loading dose over 30-60 minutes, then 25-50 mg/kg q8h (or as CRI at 10-20 mg/kg/hr)	q8h or CRI	Duration: Variable; typically 3-7 days or as needed Notes: Administer slowly to avoid hypotension. Monitor for signs of thrombosis.
Cat	PO	50-100 mg/kg loading dose, then 25-50 mg/kg q8h	q8h	Duration: Variable; typically 3-7 days or as needed Notes: Use with caution in cats with renal disease. Adjust dose accordingly.
Cat	IV	50-100 mg/kg loading dose over 30-60 minutes, then 25-50 mg/kg q8h (or as CRI at 10-20 mg/kg/hr)	q8h or CRI	Duration: Variable; typically 3-7 days or as needed Notes: Administer slowly to avoid hypotension. Monitor for signs of thrombosis.
Horse	PO	20-40 mg/kg q8h	q8h	Duration: Variable; typically 3-5 days or as needed Notes: For EIPH, administer 1-2 hours before exercise. Adjust dose in renal impairment.
Horse	IV	20-40 mg/kg loading dose, then 10-20 mg/kg q8h	q8h	Duration: Variable; typically 3-5 days or as needed Notes: Administer slowly to avoid hypotension. Monitor for signs of thrombosis.
Cattle	PO	Not established; extrapolate from other species with caution	Not established	Duration: Not established Notes: Not commonly used; consult veterinary pharmacologist.
Small Ruminants	PO	Not established; extrapolate from other species with caution	Not established	Duration: Not established Notes: Not commonly used; consult veterinary pharmacologist.
Rabbit	PO	Not established; extrapolate from other species with caution	Not established	Duration: Not established Notes: Not commonly used; consult veterinary pharmacologist.
Birds/Poultry	PO	Not established; extrapolate from other species with caution	Not established	Duration: Not established Notes: Not commonly used; consult veterinary pharmacologist.

Clinical Indications & Species Uses

General Indications

Treatment of excessive bleeding due to hyperfibrinolysis
Adjunct in surgical procedures to reduce blood loss
Management of bleeding associated with trauma or coagulopathies

Dog (Canine)

Treatment of bleeding associated with hyperfibrinolysis
Adjunct in surgical bleeding (e.g., hemangiosarcoma, nasal bleeding)
Management of bleeding disorders such as von Willebrand disease (off-label)
Treatment of oral bleeding in dogs with congenital coagulopathies

Cat (Feline)

Treatment of bleeding associated with hyperfibrinolysis
Adjunct in surgical bleeding (off-label)
Management of bleeding disorders such as hemophilia (off-label)

Horse (Equine)

Treatment of bleeding associated with hyperfibrinolysis
Management of exercise-induced pulmonary hemorrhage (EIPH) (off-label)
Adjunct in surgical bleeding

Pharmacology & Mechanism of Action

Drug Class: Antifibrinolytic Agent | Pharmacological Group: Synthetic Lysine Analog

Mechanism of Action: Aminocaproic acid is a synthetic derivative of the amino acid lysine. It competitively inhibits the activation of plasminogen to plasmin, primarily by binding to the kringle domains of plasminogen, thereby preventing its binding to fibrin. This action inhibits fibrinolysis, stabilizing blood clots and reducing bleeding. At higher concentrations, it also directly inhibits plasmin activity.

Pharmacodynamics: Aminocaproic acid exerts its effects by inhibiting both plasminogen activators and, to a lesser extent, plasmin itself. This results in decreased breakdown of fibrin clots, leading to enhanced hemostasis. The drug is most effective in conditions with hyperfibrinolysis. It does not affect the coagulation cascade directly but preserves existing clots.

⚡ Pharmacokinetics Summary

Absorption: Aminocaproic acid is rapidly and well absorbed after oral administration, with peak plasma concentrations occurring within 1-2 hours. Bioavailability is approximately 100%.

Distribution: It is widely distributed throughout the body, including into synovial fluid, pleural fluid, and cerebrospinal fluid. It crosses the placenta and is distributed into milk. The volume of distribution is approximately 0.3-0.4 L/kg in humans.

Metabolism: Aminocaproic acid is minimally metabolized in the liver; the majority of the drug is excreted unchanged in the urine.

Excretion: Renal excretion is the primary route of elimination, with about 80-90% of the dose excreted unchanged in the urine within 12 hours. Renal clearance is high, and dose adjustment is necessary in patients with renal impairment.

Half-Life: The elimination half-life is approximately 1-2 hours in dogs and cats, and about 2 hours in horses.

Bioavailability: Oral bioavailability is essentially complete (approximately 100%).

Protein Binding: Plasma protein binding is negligible (<5%).

Available Formulations & Strengths

Oral Tablet 500 mg, 1000 mg (PO)

Oral Solution 250 mg/mL (PO)

Injectable Solution 250 mg/mL (IV)

Contraindications & Clinical Warnings

Contraindications:

Active disseminated intravascular coagulation (DIC) without concurrent heparin therapy
Known hypersensitivity to aminocaproic acid
Evidence of active intravascular clotting or thrombosis
Severe renal impairment (dose adjustment required; contraindicated if anuria)

Warnings & Clinical Precautions:

Use with extreme caution in patients with cardiac, hepatic, or renal disease
Avoid rapid IV administration to prevent hypotension and bradycardia
Monitor for signs of thrombosis (e.g., limb swelling, dyspnea, neurological signs)
Use with caution in patients with hematuria of upper urinary tract origin (risk of clot obstruction)
Safety in pregnant or lactating animals has not been established; use only if clearly needed
In horses, use with caution in those with a history of thrombosis or hypercoagulable states
Not approved for food animals; extra-label use requires veterinary oversight and extended withdrawal times

Adverse Effects & Reactions

Common:

Nausea
Vomiting
Diarrhea
Hypotension (with rapid IV administration)
Dizziness (in humans; may manifest as ataxia in animals)

Serious / Severe:

Thrombosis (deep vein thrombosis, pulmonary embolism)
Myopathy (especially with prolonged high doses)
Cardiac arrhythmias
Renal failure (especially with underlying renal disease)
Seizures (with rapid IV administration)

Rare:

Allergic reactions (rash, anaphylaxis)
Hyperkalemia
Elevated creatine kinase
Ocular effects (retinal changes) with long-term use

Key Drug Interactions

Interacting Drug / Class	Clinical Effect & Mechanism	Severity
Heparin	Aminocaproic acid may antagonize the anticoagulant effect of heparin; concurrent use may increase risk of thrombosis.	Moderate
Oral Contraceptives (Estrogens)	Additive prothrombotic effects; increased risk of thromboembolism.	High
Factor IX Complex Concentrates	Increased risk of thrombosis when used concurrently.	High
Tranexamic Acid	Additive antifibrinolytic effects; increased risk of thrombosis.	Moderate
Thrombolytic Agents (e.g., streptokinase, tPA)	Antagonizes the thrombolytic effect; avoid concurrent use.	High

Overdose & Toxicity Management

Signs of Toxicity:

Hypotension
Bradycardia
Cardiac arrhythmias
Seizures
Acute renal failure
Myopathy
Thrombosis

Emergency Treatment Protocol: Treatment is primarily supportive. Discontinue the drug immediately. Administer IV fluids to maintain blood pressure and renal perfusion. For severe hypotension, use vasopressors. For seizures, administer anticonvulsants (e.g., diazepam). Monitor renal function, cardiac status, and coagulation parameters. In cases of massive overdose, consider hemodialysis (aminocaproic acid is dialyzable).

Food Animal Withdrawal Times

🥩 Meat: 30 days🥛 Milk: 7 days

Aminocaproic acid is not approved for food animals. Withdrawal times are extrapolated and must be determined by a veterinarian; a minimum of 30 days for meat and 7 days for milk is recommended, but longer may be necessary based on individual pharmacokinetics and regulatory requirements.

Storage, Handling & Regulatory Information

Storage Temperature: Store at room temperature (20-25°C, 68-77°F); protect from freezing.

Handling & Special Conditions: Keep container tightly closed. Protect from moisture. For injectable solutions, use only if clear and colorless; discard any unused portions.

Dispensing Status: Prescription Required (Rx Only)

Approval Status: Not FDA-approved for veterinary species; approved for human use.

Extra-Label (Off-Label) Use: In the US, aminocaproic acid is not FDA-approved for veterinary use; its use in animals is extra-label. Under AMDUCA, extra-label use is permitted by or on the order of a licensed veterinarian within a valid VCPR, provided that appropriate withdrawal times are established for food animals.

Clinical Pearls & Practice Notes

💡 Clinical Insights: Aminocaproic acid is a valuable antifibrinolytic agent in veterinary medicine, particularly for managing bleeding associated with hyperfibrinolysis. It is most commonly used in dogs for conditions such as hemangiosarcoma-related bleeding, nasal bleeding, and as an adjunct in surgical procedures. In horses, it is used off-label for exercise-induced pulmonary hemorrhage (EIPH). The drug is generally well-tolerated, but careful monitoring for thromboembolic events is essential, especially in patients with predisposing factors. Dosage adjustments are required in renal impairment. For food animals, extra-label use requires strict adherence to withdrawal times. Always consider the underlying cause of bleeding; aminocaproic acid is not effective for bleeding due to coagulopathies without a hyperfibrinolytic component. It should not be used in patients with DIC unless heparin is concurrently administered. Clinical response should be monitored by assessing bleeding cessation and coagulation parameters.

References & Literature

📚 Plumb's Veterinary Drug Handbook
📚 Papich Veterinary Pharmacology and Therapeutics
📚 Compendium of Veterinary Products (CVP)