Albumin (Human and Canine)
**Albumin** is a natural protein colloid utilized primarily in critical care settings to manage severe hypoalbuminemia and hypovolemia. It plays a crucial role in maintaining intravascular oncotic pressure. * **Human Serum Albumin (HSA):** Frequently used in veterinary medicine due to availability, but its use as a 'xeno-albumin' (cross-species transfusion) in dogs and cats carries significant risks of severe, potentially fatal immune-mediated hypersensitivity reactions. * **Canine Specific Albumin:** Commercially available as a lyophilized product, which significantly reduces the risk of species-specific hypersensitivity, though clinical data remains somewhat limited compared to HSA. > **Clinical Pearl:** The use of human albumin in healthy dogs (e.g., for simple volume expansion) is strongly discouraged due to a higher observed incidence of severe delayed hypersensitivity (Type III/serum sickness) compared to critically ill, immunosuppressed patients.
Mechanism: Albumin is the primary plasma protein responsible for maintaining intravascular volume. * **Oncotic Pressure:** Provides 75-80% of the oncotic pressure of plasma → reduces hydrostatic pressure → prevents crystalloid fluids from leaking into the interstitium → decreases edema and improves organ perfusion. * **Transport & Binding:** Acts as a carrier protein, binding and transporting drugs, ions, hormones, lipids, and metals (like iron). * **Endothelial & Systemic Effects:** Maintains endothelial integrity, exerts **antioxidant** properties (via thiol groups), aids in acid-base balance, decreases platelet aggregation, and augments antithrombin activity.
Dosing by species
- Refractory hypotension or severe hypoalbuminemia (using 25% Human Albumin) · Test dose of 0.25 mL/kg/h is given over 15 minutes. The maximum volume administered to any dog by the author is 25 mL/kg (6.25 g/kg) administered continuously over 72 hours; the mean volume administered to any dog overall is 5 mL/kg (1.25 g/kg). The maximum volume given as a slow push or bolus to treat hypotension is 4 mL/kg (1 gram/kg), with a mean volume of 2 mL/kg (0.5 g/kg). The range for a continuous rate infusion (CRI) after a bolus administration is 0.1 to 1.7 mL/kg/h (0.025-0.425 g/kg) over 4 to 72 hours. · IV · CRI or bolus · 4 to 72 hours · Discontinue infusion if adverse signs develop. Infusions are empirically selected to meet low normal values.
- Marked hypoalbuminemia (using 10% Human Albumin) · albumin deficit (g) = 10 X (serum albumin desired - serum albumin of patient) X body weight (kg) X 0.3. Alternatively, some dogs received 0.5 to 1.25 g/kg. · IV · over a 12-hour period · 12 hours · Dilute 25% human albumin to a 10% solution with 0.9% NaCl. Administer with a transfusion filter. No dog is eligible for additional human albumin after 7 days following initial administration.
- Hypovolemic shock or hypoalbuminemia (using Canine Albumin 5g lyophilized) · A total of 2.5-5 mL/kg body weight is recommended. Administer IV at a dosage rate of 1 mL/min. · IV · Single dose · Until calculated volume is administered · Dilute to 16% (add 30 mL of diluent such as sterile normal saline, Normosol or dextrose 5%).
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Routes of administration
Contraindications
- History of hypersensitivity to albumin (human or canine)
- Repeat administration of xeno-albumin (human albumin in dogs) beyond 7 days
- Healthy animals with simple volume depletion (avoid xeno-albumin)
- Pre-existing conditions resulting in volume overload
- Severe anemia or extreme dehydration (unless concurrent RBCs or appropriate crystalloid fluids are administered first)
Adverse effects
- Immediate hypersensitivity (anaphylaxis, facial edema, vomiting, urticaria, hyperthermia, shock)
- Delayed hypersensitivity / Type III serum sickness (lethargy, lameness, peripheral edema, cutaneous lesions/vasculitis, renal failure, coagulopathies)
- Volume overload
- Diarrhea
- Tremors
- Perivascular inflammation at catheter sites
Drug interactions
- Highly protein-bound drugs · Exogenous albumin may bind to these drugs, potentially affecting the amount of free (active) drug circulating, though this rarely appears to be clinically significant.
Monitoring
- Pre- and post-infusion serum albumin (target 2.0-2.5 g/dL)
- Pre- and post-infusion colloid osmotic pressure (COP)
- Vital signs: body temperature, respiratory rate, blood pressure, and heart rate
- Signs of volume overload (e.g., increased respiratory effort, chemosis)
- Immediate hypersensitivity (facial edema, vomiting, urticaria)
- Delayed hypersensitivity reactions (can occur weeks after administration)
Overdose
Overdosage can lead to **hyperalbuminemia** and **hyperproteinemia**, resulting in severe volume overload and hyperviscosity. To avoid these effects, serum albumin levels should be closely monitored. Most experts recommend that serum albumin should not exceed **2.5 g/dL** (some suggest a strict maximum of 2.0 g/dL) when used clinically.
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.