Objective—To evaluate the safety of an orally administered
ivermectin and praziquantel paste with regard
to variables associated with clinical findings, parturition,
lactation, maternal care, and neonate viability in
Animals—40 pregnant mares.
Procedure—Mares were randomly allocated into
treatment (n = 20) and control (20) groups and administered
a placebo or 3 times the therapeutic dosage of
ivermectin (0.6 mg/kg) and praziquantel (4.5 mg/kg) at
14-day intervals until parturition. Physical examinations
were performed on mares and their foals after
parturition (on postpartum days 30, 60, and 90) to
identify any drug-related effects. As an aid in assessing
general health, hematologic and serum biochemical
analyses were performed monthly on the mares.
Results—In blood constituents, minor alterations that
were not biologically important were observed.
Reproductive performance was not affected by the
unusual treatment duration or high dosage, although
the drugs were administered during a crucial period of
equine embryonic development (30 to 60 days).
Neither adverse effects on mares nor abortions
occurred. Follow-up evaluations of the foals for a 3-
month period did not detect any abnormalities.
Conclusions and Clinical Relevance—Administration
of the ivermectin-praziquantel paste appears
to be safe in pregnant mares and their foals.
(Am J Vet Res 2003;64:1221–1224)