Greyhounds do not tolerate anaesthetics or sedation well. They have  relatively little body fat and are thus unable to absorb lipidsoluable  thiobarbiturates therefore remain systematically active for a greater  period of time. Consequently, Greyhounds are especially susceptible to  hypothermia and hypotension while anaesthetized with thiobarbiturates.

The following suggestions are taken from Greyhound Pets Quarterly:

• Greyhounds must have fluids during ALL surgical procedures.
• NEVER use the thiobarbiturates, including Biotal, Surital, or Pentothol.
• An EXCELLENT choice for anaesthetic for use on greyhounds is a  synthetic narcotic human drug known generically as Oxymorphone.  It is supplied in 1.5 mg/ml in 10cc vials and is marketed by the Endo Drug Company under the name of Numorphan. It is almost fully reversible through the use of narcotic-reversing agents such as Nalline or Levallophan.
• A gas anaesthetic, such as Methophane, is not necessary if the  patient has achieved a level of deep depression.

And the following procedures are recommended for the surgical  anaesthetizing of greyhounds:

ALL greyhounds receiving atrophine sulphate prior to anaesthesia and  intravenous fluids during general anaesthesia. 0.05mg/lb of Oximorphone  is combined in a single syringe with 0.1ml/10lbs of Acepromazine (3.0mg  Oximorphone and .6cc Acepromazine for a 60 lb dog). This combination is  injected intravenously over a 15-20 second period; faster injection can  result in a brief excitement phase. Apprehensive dogs can receive as much  as 0.075mg/lb. of Oxymorphone.

Within 5 minutes the dog can be intubated with very little manual  restraint. Many animals will respond excessively to noise at this stage.  Depending upon the procedure, as well as the level of depression the  patient has achieved, one may or may not incorporate the use of Metophan,  a gas anaesthetic. Upon completion of the surgery, Nalline is injected  intravenously at a dosage equivalent to the induction dosage of the  Oxymorphone.

Further information on the subject of the use of anaesthesia in  Greyhounds can be obtained by contacting the Small Animal Teaching  Hospital of Colorado State University at Fort Collins, Colorado  (303-484-9154). Because Greyhounds are slow in recovering from the  effects of sedation and anaesthesia, it is reccommended that you leave  your pet under observation by your vet. the night following any surgery  which is performed under general anaesthetic.