The choice of drugs administered during premedication depends on species, temperament, physical status, the procedure to be performed and the clinician’s experience with the medication.  

Objectives of premedication - Premedication drugs are administered to minimize patient stress and anxiety and to facilitate restraint and enhance the safety of the patient and staff.  Premedication drugs decrease the amount of injectable and inhalant anesthetics required and facilitate a smooth transition between anesthetic phases and improving cardiopulmonary stability. 

Premedication drugs also provide essential, preemptive and perioperative pain management and reduce overall analgesic requirements. Finally, drugs used to decrease autonomic reflex activity provide a more stable plane of anesthesia and reduce potential cardiac arrhythmias.


  • Minimizes stress and anxiety
  • Facilitates restraint
  • Enhances staff safety
  • Reduces autonomic activity

Catheterization – As the premedication drug takes full effect, an intravenous catheter is inserted to provide rapid administration of drugs while avoiding perivascular administration.  Additionally, an intravenous catheter facilitates administration of intravenous fluids to maintain vascular volume, which decreases as a result of anesthetic drugs, blood loss, and insensible fluid loss.  

Finally, the intravenous port provides immediate access to the circulation should emergency drugs be required.  
Pre-oxygenation - Administration of supplemental oxygen reduces the risk of hemoglobin desaturation and hypoxemia during anesthetic induction.  It is especially beneficial if a difficult or prolonged intubation is expected or if the patient is already dependent on supplemental oxygen. 

It is a best practice to continue pre-oxygenation until it is determined the patient is ready to be intubated.  During pre-oxygenation, connect and activate the ECG and blood pressure monitors to observe how the cardiovascular system has been affected by pre-medications.

Anesthesia best practice:  Continue to administer supplemental oxygen until the patient is deemed ready for intubation