Propofol is a widely used injectable anesthetic in small animal veterinary anesthesia. This staple drug provides reliable and rapid induction, short-duration anesthesia, and quick recovery for sedated procedures and anesthetic events.
As a veterinary professional, you may have questions about the appropriate and safe use of propofol, or need a refresher on how propofol works, when to choose it over other drugs, and the adverse events to watch for in your patients. Explore the most common questions veterinary professionals have about using propofol.
Key Takeaways
- Propofol is a fast-acting, short-duration anesthetic commonly used for induction and short procedures in small animal veterinary medicine.
- Propofol can cause hypotension and apnea, necessitating careful dose titration, monitoring, and support.
- A combination of hepatic and extrahepatic metabolism makes propofol ideal for seniors and pets with liver disease.
- Preserved propofol formulations can help clinics reduce waste.
1. What are the key properties of propofol?
Propofol is a highly lipid-soluble phenol derivative that acts on the GABA-A receptor to increase inhibitory neurotransmission in the CNS and induce short-acting anesthesia. Propofol is administered intravenously (IV) because its lipid solubility makes absorption via other routes unpredictable.
Key properties of propofol include:
- Rapid onset of action — Starts working within 30 to 60 seconds after quickly crossing the blood-brain barrier
- Short duration of action — Effects last five to 10 minutes as the drug redistributes from the brain to peripheral tissues
- Multi-site metabolism — Cleared by the liver and extrahepatic sites, including up to 40% metabolism in the lungs
- Flexible use — Can be given as a single bolus, intermittent dosing, or continuous rate infusion (CRI)
Propofol is most often used as an induction agent in veterinary anesthesia, but it can also be used for brief heavy sedation, total IV anesthesia, or the management of status epilepticus.
2. How does propofol affect the cardiovascular system?
Propofol causes dose- and rate-dependent cardiovascular depression. Vasodilation decreases vascular resistance and causes transient hypotension. One study found that 25% of healthy, premedicated dogs may experience a temporary drop in mean arterial pressure (MAP) around 45 to 75 seconds after administration.
For pets who have existing cardiac disease or who are hypovolemic or otherwise debilitated at the time of administration, this depression can be significant. To minimize cardiovascular effects, veterinary team members should use premedications to reduce dosing needs and always administer doses slowly and to effect.
3. How does propofol affect the respiratory system?
Propofol in veterinary anesthesia causes a brief period of apnea, which is more likely with rapid administration or with high doses. Apnea typically occurs within seconds of administration and may last up to a minute, depending on the dose and the presence of premedication.
Propofol also reduces tidal volume and respiratory rate in a dose-dependent manner. To reduce the risk of hypoxia, veterinary team members should preoxygenate pets when possible, intubate quickly, and provide ventilation support.
4. Is propofol safe for pets with hepatic or renal compromise?
Propofol is safe for pets with liver or kidney disease because it undergoes both hepatic and extrahepatic metabolism. Animals can "blow off" propofol via metabolism in the lungs, which assists the liver with drug clearance. Liver compromise does not affect metabolism or recovery time when propofol is used in veterinary anesthesia.
Renal disease is less of a concern with propofol than with other injectable agents, such as ketamine, which are more dependent on renal elimination.
5. Can I use propofol for total intravenous anesthesia (TIVA)?
Propofol works well for IV anesthesia in dogs when gas anesthetic agents aren't available or are otherwise contraindicated. Veterinary team members may administer intermittent boluses as needed during short procedures or establish a CRI for longer surgeries. In dogs, recovery from propofol is rapid and predictable, even with repeated dosing.
6. What adverse effects should I monitor for during propofol use?
The most common adverse effects of propofol during veterinary anesthesia include:
- Transient hypotension
- Respiratory depression or apnea
- Myoclonus or muscle twitching
- Excitement or dysphoria during recovery
Perivascular administration of propofol does not produce local tissue reaction, but teams should still confirm IV catheter patency before administration to ensure drug efficacy.
Veterinary teams can combat the adverse effects of propofol in veterinary anesthesia by:
- Administering boluses slowly and to effect
- Monitoring cardiorespiratory parameters
- Preoxygenating
- Being prepared to intubate and provide ventilation support
7. What's the difference between propofol formulations?
Propofol formulations differ primarily in how long they remain safe for use after opening. Unpreserved formulations are highly susceptible to bacterial contamination because they contain egg and must be discarded within 6 to 12 hours of opening.
Preserved formulations have additives that enable continued use for up to 28 days after opening, without refrigeration. These products, including PropofolVet Multidose, contain benzyl alcohol to extend in-use shelf life.
Multidose formulations have several advantages, including:
- Less packaging and product waste
- Lower cost per patient
- Equivalent safety profile to unpreserved formulas
8. When should I use propofol versus alfaxalone?
While propofol has been a staple in veterinary anesthesia for decades, alfaxalone is a newer induction agent with similar properties. Both drugs are titrated to effect slowly, have a short duration of action, and can be bolused repeatedly for sustained IV anesthesia.
However, there are a few situations where you might choose one over the other. In a 2024 study comparing cardiovascular effects of propofol and alfaxalone, hypotension occurred less frequently in the alfaxalone group, and these pets also had a transient increase in heart rate that preserved cardiac output.
Although apnea can occur with both drugs, alfaxalone may have a slight advantage in pets with pre-existing cardiovascular compromise, except when tachycardia might be harmful (e.g., hypertrophic cardiomyopathy). It's also more flexible, allowing intramuscular (IM) administration for sedation of small dogs. However, propofol's metabolism makes it a better choice for pets with hepatic insufficiency.
Trusted Veterinary Anesthesia
Propofol is a reliable anesthetic that has been used in small animal veterinary medicine for many years. The drug's rapid onset, short duration, and predictable induction and recovery make it ideal for short-duration propofol sedation and routine or emergency surgery.
Parnell manufactures FDA-approved veterinary anesthesia drugs, including PropofolVet Multidose. With a 28-day in-use shelf life, our canine anesthetic is a cost-effective option for clinics of all sizes.
If you're an early-career veterinary professional looking to build confidence in anesthesia or a veterinary leader who wants to provide the team with an anesthesia refresher, check out our Foundations of Anesthesia & Sedation Certificate Course.
