Effects of domperidone on digital laminar microvascular blood flow in clinically normal adult horses.
OBJECTIVE
To determine effects of domperidone and acepromazine maleate on microvascular blood flow in digital laminae of clinically normal adult horses.


METHODS
8 clinically normal adult horses (4 mares and 4 geldings).


METHODS
In a 4-period crossover study, domperidone was administered PO at 1.1 mg/ kg and 5.5 mg/kg and IV at 0.2 mg/kg; acepromazine was administered IV at 0.04 mg/kg. The washout period between treatments was 1 week. A 3-minute measurement of laminar microvascular blood flow (LMBF) was obtained with laser Doppler flowmetry. Baseline measurements were obtained at -2, -1, and 0 hours prior to administration of drugs. Post-treatment measurements were obtained at 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 10, and 12 hours. Percentage change from baseline values in LMBF for each treatment was subsequently calculated.


RESULTS
Oral administration of domperidone at 1.1 mg/kg and 5.5 mg/kg significantly increased LMBF, compared with baseline values, beginning 4 hours after administration, and this effect persisted for at least 8 hours. Intravenous administration of domperidone at 0.2 mg/kg significantly increased LMBF, compared with baseline values, at 10 and 12 hours after administration. Administration of acepromazine (0.04 mg/kg, IV) significantly increased LMBF, compared with baseline values, at 3, 5, 8, and 10 hours after administration. No adverse effects of drugs were detected in any horse.


CONCLUSIONS
Domperidone may be useful for preventing vasoconstriction and reduction in LMBF believed to occur in horses with laminitis, but additional research of the drug's effects in horses with laminitis is required.
Castro
José R
JR
Department of Large Animal Clinical Sciences, College of Veterinary Medicine, University of Tennessee, Knoxville, TN 37996, USA.
Adair
Henry S
HS
Radecki
Steven V
SV
Kiefer
Virginia R
VR
Elliot
Sarah B
SB
Longhofer
Susan L
SL
D000075:Acepromazine / Q000008:administration & dosage / Q000494:pharmacology; D000284:Administration, Oral; D000818:Animals; D001783:Blood Flow Velocity / Q000187:drug effects / Q000502:physiology*; D002940:Circadian Rhythm / Q000187:drug effects / Q000502:physiology; D004294:Domperidone / Q000008:administration & dosage / Q000494:pharmacology*; D018492:Dopamine Antagonists / Q000008:administration & dosage / Q000494:pharmacology; D006724:Hoof and Claw / Q000098:blood supply; D006736:Horses / Q000097:blood*; D008833:Microcirculation / Q000187:drug effects / Q000502:physiology*; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000502:physiology; D014111:Tourniquets
D018492:Dopamine Antagonists; D000075:Acepromazine; D004294:Domperidone