Section 522.2610 - Trimethoprim and sulfadiazine(a)Specifications. Each milliliter (mL) contains: (1) 40 milligrams (mg) trimethoprim suspended in a solution containing 200 mg sulfadiazine; or(2) 80 mg trimethoprim suspended in a solution containing 400 mg sulfadiazine (as the sodium salt).(b)Sponsors. See Nos. 000061 and 054771 in § 510.600(c) of this chapter.(c)Conditions of use -(1)Dogs - (i)Amount. 1 mL of the product described in paragraph (a)(1) of this section (40 mg trimethoprim and 200 mg sulfadiazine) per 20 pounds (9 kilograms) of body weight per day by subcutaneous injection.(ii)Indications for use. For the treatment of acute urinary tract infections, acute bacterial complications of distemper, acute respiratory tract infections, acute alimentary tract infections, and acute septicemia due to Streptococcus zooepidemicus.(iii)Limitations. Federal law restricts this drug to use by or on the order of a licensed veterinarian.(2)Horses - (i)Amount. 2 mL of the product described in paragraph (a)(2) of this section (160 mg trimethoprim and 800 mg sulfadiazine) per 100 pounds (45 kilograms) of body weight per day by intravenous injection as single, daily dose for 5 to 7 days. The daily dose may also be halved and given morning and evening.(ii)Indications for use. For use where systemic antibacterial action against sensitive organisms is required during treatment of acute strangles, respiratory tract infections, acute urogenital infections, and wound infections and abscesses.(iii)Limitations. Do not use in horses intended for human consumption. Federal law restricts this drug to use by or on the order of a licensed veterinarian. 71 FR 30803 , May 31, 2006, as amended at 79 FR 16197 , Mar. 25, 2014