Use of prostaglandins and bromocriptine mesylate for pregnancy termination in bitches.

Objective: To assess the efficacy and safety of 2 protocols using bromocriptine mesylate and prostaglandins to terminate unwanted pregnancy in bitches.

Design: Prospective randomized single-blind controlled study.

Animals: 34 crossbred and purebred bitches referred for possible pregnancy termination. Seven additional pregnant bitches were used as controls.

Procedure: Pregnancy was assessed by ultrasonographic examination from day 25 after mating in all bitches. Of the 34 bitches, 25 were pregnant and were randomly allocated to a treatment group. Group-1 dogs (n = 12) received a combination of increasing amounts of bromocriptine mesylate (15 to 30 microg/kg [6.8 to 13.6 microg/lb], p.o., q 12 h) and dinoprost tromethamine (0.1 to 0.2 mg/kg [0.045 to 0.09 mg/lb], s.c., q 24 h). Group-2 dogs (n =13) received a combination of increasing amounts of bromocriptine mesylate (the same schedule as group-1 dogs) and cloprostenol sodium (1 microg/kg [0.45 microg/lb], s.c., q 48 h). Both groups were treated until pregnancy termination. Results-Treatment success was 100% in both groups. Days of treatment required for pregnancy termination did not significantly differ between groups (5.0 +/- 0.6 vs 3.7 +/- 0.6 days, group-1 and group-2 dogs, respectively) although adverse effects only developed in group-1 dogs. At the end of the protocols, pseudopregnancy was observed in 3 of 12 and 6 of 13 group-1 and group-2 dogs, respectively. Pregnancy termination was followed by a mucoid sanguineous vulvar discharge for 3 to 10 days.

Conclusions And Clinical Relevance: Results of this study indicate that protocols that combine the use of bromocriptine mesylate and prostaglandins for the termination of unwanted pregnancy in bitches are efficient and safe. The use of bromocriptine mesylate and cloprostenol had the best results and could be easily used on an outpatient basis.