Section 520.2520a - Trichlorfon and atropine(a)Specifications.(1) For trichlorfon: O,O-Dimethyl 2,2,2-trichloro-1-hydroxyethyl phosphonate.(2) For atropine: Atropine N.F.(b)Sponsor. See No. 054771 in § 510.600(c) of this chapter.(c)Conditions of use in mice -(1)Amount. Administer 1.67 grams of trichlorfon and 7.7 milligrams of atropine per liter continuously for 7 to 14 days as the sole source of drinking water.(2)Indications for use. For the treatment of Syphacia obvelata (pinworm) in laboratory mice.(3)Limitations. Federal law restricts this drug to use by or on the order of a licensed veterinarian. 79 FR 28832 , May 20, 2014