VPT 321: Veterinary Neuropharmacology (2+1)

OTHER INTRAVENOUS ANAESTHETICS

Saffan (Althesin) (9 mg alphaxolone + 3 mg alphadolone) both steroids

• High therapeutic index with wide margin of safety
• Good muscle relaxation
• Mild cardiovascular and Respiratory depression
• Can be given both by intravenous or intramuscular
• (5-6 mg /kg)
• No irritation on escape into subcutaneous sites
• Contraindicated in dogs – due to histamine release by the vehicle

Chloral hydrate

• Volatilizing crystalline substance
• Reduced to 2,2,2-trichloroethanol – which is the narcotic agent
• Hypnotic agent
• Slow onset –difficult to assess the depth of anaesthesia
• Perivascular escape severe reaction
• Used in Large Animals –sometimes with barbiturates
• 12% Chloral hydrate + 6% MgSO₄ intravenous in Large Animals for anaesthesia
• Has low margin of safety
• Not used now a days - since better agents are available

Chloralose

• Glucose + chloral hydrate
• Long shallow depth and slow recovery
• Not used

Urethane – Carcinogenic and discontinued

Metomidate

• Non Barbiturate intravenous anaesthetic – imidazole product
• Developed as hypnotic in pigs
• Poor analgesia but strong muscle relaxation
• Remarkable stability of the CVS
• Used for restraint of birds apart from pigs

Etomidate : (hypnomidate)

• Low CVS toxicity
• Release histamine but in general low respiratory depression
• Suppresses adrenocortical function
• Expensive and not popular