crotoxyphos and phenothiazine

Toxicity and interaction of topical application of dichlorvoscrotoxyphos (D-C) insecticide and phenothiazine anthelmintic (PTZ) given in the diet were studied in 4 groups of 4-5 lambs each that had had prior drug exposure. In a study reported previously each lamb in groups 1 and 2 was sprayed with 3 biweekly topical applications of 1550 ml of 0.25% D-C emulsion. Groups 1 and 3 were treated with PTZ (12.5 g/sheep initially and 4 days later with 6.25 g every 3 days for 9 treatments). Group 4 was the control. Following termination of that study the animals were given a 30-day nonmedicated period and reused in the present study as described below. Each lamb in group 1 and 3 was challenged with PTZ given in the diet (1g/sheep/day for 3 days). On the third day of PTZ administration, each lamb in group 1 and 2 was sprayed with 1 gallon of 0.25% D-C emulsion. The 4th group served as a control. Following D-C spray, clinical signs of toxicosis were seen within 17 min in 56% of the exposed lambs regardless of concurrent PTZ treatment. The erythrocyte acetylcholinesterase (EACE) activities of the D-C exposed groups were significantly (P less than 0.05) depressed on post-treatment days (PTD) 1 and 3 regardless of the PTZ treatment. The base-line EACE values were reestablished on PTD 18. The PTZ alone was not toxic and did not inhibit EACE activity.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Acetylcholinesterase; Animal Feed; Animals; Anthelmintics; Behavior, Animal; Dichlorvos; Drug Interactions; Erythrocytes; Female; Insecticides; Organophosphorus Compounds; Phenothiazines; Sheep; Time Factors

The temporal interaction of an emulsifiable mixture of 2.3% dichlorvos and 10% crotoxyphos with phenothiazine anthelmintic was studied in 8 groups of 5 lambs each, free from or parasitized with Haemonchus and Trichostrongylus spp. Each lamb in 1 of 3 parasitized groups and 1 of 3 nonparasitized groups was treated with phenothiazine orally (12.5 g initially and 4 days later with 6.25 g every 3 days for 9 treatments) and/or the mixture of dichlorvos and crotoxyphos dermally (1,550 ml of 0.25% emulsion sprayed every 2 weeks for 3 applications). Two groups served as controls. Onset of clinical signs of toxicosis, lethality, and erythrocyte acetylcholinesterase (EACE) activity were monitored. After each dichlorvos-crotoxyphos mixture spray, clinical signs of toxicosis were seen within 40 minutes in parasitized and nonparasitized lambs regardless of concurrent phenothiazine treatment. Phenothiazine alone was not toxic and did not inhibit EACE activity. The EACE activities of dichlorvos-crotoxyphos mixture-sprayed lambs were significantly (P less than 0.05) depressed regardless of parasitism or concurrent phenothiazine treatments. The severity of inhibition increased with each dichlorvos-crotoxyphos mixture spray, but EACE activity recovered within 48 hours after each spray although base-line values were never attained. There was no apparent potentiation of the toxic effects of the dichlorvos-crotoxyphos mixture by phenothiazine.

Topics: Animals; Dichlorvos; Drug Interactions; Female; Haemonchiasis; Insecticides; Organophosphorus Compounds; Phenothiazines; Sheep; Sheep Diseases; Swine; Trichostrongyloidiasis; Trichostrongylosis