21 C.F.R. § 520.600 Dichlorvos.
Title 21 - Food and Drugs
(a) Chemical name. 2,2-Dichlorvinyl dimethyl phosphate. (b) [Reserved] (c) Sponsor. See No. 000010 in §510.600(c) of this chapter. (d) Related tolerances. See §556.180 of this chapter. (e) Conditions of use in swine. (1) It is recommended for the removal and control of sexually mature (adult), sexually immature and/or 4th stage larvae of the whipworm (Trichuris suis), nodular worms (Oesophagostomum spp.), large round-worm (Ascaris suum), and the mature thick stomach worm (Ascarops strongylina) occurring in the lumen of the gastrointestinal tract of pigs, boars, and open or bred gilts and sows. (2) The preparation should be added to the indicated amount of feed as set forth in paragraph (e)(2) of this section and administered shortly after mixing, as follows: (3) Do not use this product on animals either simultaneously or within a few days before or after treatment with or exposure to cholinesterase inhibiting drugs, pesticides, or chemicals. The preparation should be mixed thoroughly with the feed on a clean, impervious surface. Do not allow swine access to feed other than that containing the preparation until treatment is complete. Do not treat pigs with signs of scours until these signs subside or are alleviated by proper medication. Resume normal feeding schedule afterwards. Swine may be retreated in 4 to 5 weeks. (f) Conditions of use in dogs. (1) For removal of Toxocara canis and Toxascaris leonina (roundworms), Ancylostoma caninum and Uncinaria stenocephala (hookworms), and Trichuris vulpis (whipworm) residing in the lumen of the gastrointestinal tract. (2) The drug is in capsule form for direct administration and in pellet form for administration in about one-third of the regular canned dog food ration or in ground meat. Dogs may be treated with any combination of capsules and/or pellets so that the animal receives a single dose equaling 12 to 15 milligrams of the active ingredient per pound of body weight. One-half of the single recommended dosage may be given, and the other half may be administered 8 to 24 hours later. This split dosage schedule should be used in animals which are very old, heavily parasitized, anemic, or otherwise debilitated. The drug should not be used in dogs weighing less than 2 pounds. (3) In some dogs, efficacy against Trichurias vulpis (whipworm) may be erratic. Dogs that do not develop a negative stool for Trichuris vulpis ova 10 to 14 days following initial treatment should be re-treated. If a negative stool is not obtained in 10 to 14 days following re-treatment, alternate means of therapy should be considered. (4) Do not use in dogs infected with Dirofilaria immitis. (5) Do not use with other anthelmintics, taeniacides, antifilarial agents, muscle relaxants, or tranquilizers. (6) The drug is a cholinesterase inhibitor. Not for use simultaneously or within a few days before or after treatment with or exposure to cholinesterase-inhibiting drugs, pesticides, or chemicals. (7) Federal law restricts this drug to use by or on the order of a licensed veterinarian. (g) Conditions of use in horses when administered in grain. (1) It is recommended for the removal and control of bots (Gastrophilus intestinalis, G. nasalis), large strongyles (Strongylus vulgaris, S. equinus, S. edentatus), small strongyles (of the genera Cyathostomum, Cylicocercus, Cylicocyclus, Cylicodontophorus, Triodontophorus, Poteriostomum, Gyalocephalus), pinworms (Oxyuris equi), and large roundworm (Parascaris equorum) in horses including ponies and mules. Not for use in foals (sucklings and young weanlings). (2) For a satisfactory diagnosis, a microscopic fecal examination should be performed by a veterinarian or a diagnostic laboratory prior to worming. (3) It is administered in the grain portion of the ration at a dosage of 14.2 milligrams to 18.5 milligrams per pound of body weight as a single dose. It may be administered at one-half of the single recommended dosage and repeated 8 to 12 hours later in the treatment of very aged, emaciated or debilitated subjects or those reluctant to consume medicated feed. In suspected cases of severe ascarid infection sufficient to cause concern over mechanical blockage of the intestinal tract, the split dosage should be utilized. (4) Do not use in horses which are severely debilitated, suffering from diarrhea or severe constipation, infectious disease, toxemia or colic. Do not administer in conjunction with or within 1 week of administration of muscle relaxant drugs, phenothiazine derived tranquilizers or central nervous system depressant drugs. Horses should not be subjected to insecticide treatment for 5 days prior to or after treating with the drug. Do not administer to horses afflicted with chronic alveolar emphysema (heaves) or related respiratory conditions. The product is a cholinesterase inhibitor and should not be used simultaneously or within a few days before or after treatment with or exposure to cholinesterase inhibiting drugs, pesticides or chemicals. (5) Do not use in animals other than horses, ponies, and mules. Do not use in horses, ponies, and mules intended for food purposes. Do not allow fowl access to feed containing this preparation or to fecal excrement from treated animals. (h) Conditions of use in horses when administered orally by syringe. (1) It is recommended for the removal and control of first, second, and third instar bots (Gastrophilus intestinalis and G. nasalis), sexually mature and sexually immature (4th stage) ascarids (Parascaris equorum) in horses and foals. (2) The product is in the form of a gel which is administered directly from a syringe onto the horse's tongue. The product is administered at a dosage level of 20 milligrams of dichlorvos per kilogram of body weight for the removal of bots and ascarids. The same dosage level is repeated every 21 to 28 days for the control of bots and ascarids. For the control of bots only, the repeat dosage is 10 milligrams per kilogram of body weight every 21 to 28 days during bot fly season. (3) Do not use this product in animals simultaneously or within a few days before or after treatment with or exposure to cholinesterase-inhibiting drugs, pesticides or chemicals. Do not administer in conjunction with or within 1 week of administration of muscle-relaxant drugs, phenothiazine derived tranquilizers, or central nervous system depressants. (4) Do not use in horses which are severly debilitated or suffering from diarrhea or severe constipation, infectious disease, toxemia, or colic. Do not administer to horses affected with chronic alveolar emphysema (heaves) or other respiratory conditions. (5) Do not use in horses intended for food purposes. (6) Federal law restricts this drug to use by or on the order of a licensed veterinarian. (i) Conditions of use in dogs, cats, puppies, and kittens. (1) Each tablet contains 2, 5, 10, or 20 milligrams of dichlorvos. (2) It is administered orally at 5 milligrams of dichlorvos per pound of body weight. (3) Dogs and puppies: Removal and control of intestinal roundworms (Toxocara canis and Toxascaris leonina) and hookworms (Ancylostoma caninum and Uncinaria stenocephala). (4) Cats and kittens: Removal and control of intestinal roundworms (Toxocara cati and Toxascaris leonina) and hookworms (Ancylostoma tubaeforme and Uncinaria stenocephala). (5) Dichlorvos is a cholinesterase inhibitor. Do not use simultaneously with or within a few days before or after treatment with or exposure to cholinesterase-inhibiting drugs, pesticides, or chemicals. (6) Do not use in animals under 10 days of age or 1 pound of body weight. (7) Do not administer to animals showing signs of constipation, mechanical blockage of the intestinal tract, impaired liver function, or recently exposed to or showing signs of infectious disease. (8) Do not use in dogs or puppies infected with Dirofilaria immitis. (9) Federal law restricts this drug to use by or on the order of a licensed veterinarian. [40 FR 13838, Mar. 27, 1975, as amended at 48 FR 40704, Sept. 9, 1983; 51 FR 28546, Aug. 8, 1986; 62 FR 35076, June 30, 1997; 64 FR 18571, Apr. 15, 1999]
Title 21: Food and Drugs
PART 520—ORAL DOSAGE FORM NEW ANIMAL DRUGS
§ 520.600 Dichlorvos.
------------------------------------------------------------------------ Pounds of Pounds of mixed feed Number of feed to be to be pigs to be Weight of animal in pounds mixed with administered treated each 0.08 to each pig per 0.08 ounce of as a single ounce of dichlorvos treatment dichlorvos------------------------------------------------------------------------20-30............................. 4 0.33 1231-40............................. 5 0.56 941-60............................. 6 1.00 661-80............................. 5 1.00 581-100............................ 4 1.00 4Adult Gilts, Sows, and Boars...... 16 4.00 4------------------------------------------------------------------------
