Section 520.1631 - Oxfendazole and trichlorfon paste(a)Specifications. Each gram of paste contains 28.5 milligrams oxfendazole and 454.5 milligrams trichlorfon.(b)Sponsor. See 054771 in § 510.600(c) of this chapter.(c)Conditions of use - (1)Amount. 2.5 milligrams of oxfendazole and 40 milligrams of trichlorfon per kilogram of body weight.(2)Indications for use. The drug is used in horses for removal of bots (Gasterophilus intestinalis, 2nd and 3rd instars; G. nasalis, 3rd instar) and the following gastrointestinal worms: Large roundworms (Parascaris equorum), pinworms (Oxyuris equi), adult and 4th stage larvae; large strongyles (Strongylus edentatus, S. vulgaris, and S. equinus); and small strongyles.(3)Limitations. Horses maintained on premises where reinfection is likely to occur should be retreated in 6 to 8 weeks. Withholding feed or water before use is unnecessary. Administer with caution to sick or debilitated horses. Not for use in horses intended for food. Do not administer to mares during the last month of pregnancy. Trichlorfon is a cholinesterase inhibitor. Do not use this product in animals simultaneously with, or within a few days before or after treatment with or exposure to, cholinesterase-inhibiting drugs, pesticides, or chemicals. Consult your veterinarian for assistance in the diagnosis, treatment, and control of parasitism.50 FR 50291, Dec. 10, 1985, as amended at 61 FR 5506, Feb. 13, 1996; 78 FR 28825 , May 20, 2014