Comparison of sedative effects of romifidine following intravenous, intramuscular, and sublingual administration to horses.
OBJECTIVE
To compare sedative effects of romifidine following IV, IM, or sublingual (SL) administration in horses.


METHODS
30 horses that required sedation for routine tooth rasping.


METHODS
Horses (n = 10/group) were given romifidine (120 microg/kg) IV, IM, or SL. Heart rate, respiratory rate, head height, distance between the ear tips, thickness of the upper lip, response to auditory stimulation, response to tactile stimulation, and degree of ataxia were recorded every 15 minutes for 180 minutes. Tooth rasping was performed 60 minutes after administration of romifidine, and overall adequacy of sedation was assessed.


RESULTS
IV and IM administration of romifidine induced significant sedation, but SL administration did not induce significant sedative effects. Scores for overall adequacy of sedation after IV and IM sedation were not significantly different from each other but were significantly different from scores for horses given romifidine SL. Sedative and other effects varied among groups during the first 60 minutes after drug administration; thereafter, effects of IV and IM administration were similar.


CONCLUSIONS
Onset of action was fastest and degree of sedation was greater after IV, compared with IM, administration of romifidine, but duration of action was longer after IM administration. Sublingual administration did not result in clinically important sedative effects.
Freeman
S L
SL
Department of Farm Animal and Equine Medicine and Surgery, Royal Veterinary College, University of London, Hatfield, Hertfordshire.
England
G C
GC
D000161:Acoustic Stimulation; D000286:Administration, Sublingual; D000777:Anesthetics / Q000008:administration & dosage / Q000494:pharmacology*; D000818:Animals; D005260:Female; D006309:Hearing / Q000187:drug effects; D006339:Heart Rate / Q000187:drug effects; D006736:Horses / Q000502:physiology* / Q000601:surgery; D007093:Imidazoles / Q000008:administration & dosage / Q000494:pharmacology*; D007273:Injections, Intramuscular / Q000662:veterinary; D007275:Injections, Intravenous / Q000662:veterinary; D008297:Male; D009126:Muscle Relaxation / Q000187:drug effects; D011897:Random Allocation; D012119:Respiration / Q000187:drug effects; D014070:Tooth / Q000601:surgery; D014110:Touch / Q000187:drug effects
D000777:Anesthetics; D007093:Imidazoles; C076257:romifidine