The U.S. Food and Drug Administration has approved Equidone Gel (domperidone) for the prevention of fescue toxicosis, a disease that can cause serious reproductive problems in horses.
Equidone Gel, the first FDA-approved drug to prevent fescue toxicosis, is a dopamine antagonist (D2 receptors) that works at the cellular level to block the agonistic action of toxins produced by an endophytic fungus living on fescue grass. Equidone Gel is administered orally by syringe once a day.
Fescue is a type of grass and makes up over 35 million acres of pastureland in the U.S. The endophytic fungus, called Neotyphodium coenophialum (previously known as Acremonium coenphalium), lives on the grass and produces toxins that interfere with the hormones involved in pregnancy and milk production. Mares grazing on tall fescue pastures infected with the toxin can suffer from the following: increased length of pregnancies; difficulty giving birth; mare and foal deaths; weak, stillborn, or immature foals; agalactia (absent milk production after birth); retained placentas; premature separation of the placenta at birth; and increased placental weights and thickness.
The safety and effectiveness of Equidone Gel was evaluated in both laboratory and field studies. The laboratory studies included a margin of safety study in healthy mares and an effectiveness study evaluating mares with induced disease. Two field studies corroborated the findings of the laboratory studies under field conditions.
The most common side effects reported in the studies were premature lactation (dripping of milk prior to foaling) and failure of passive transfer (immunoglobulins to the foal).
Equidone Gel is marketed and distributed by Dechra Veterinary Products of Overland Park, Kansas.