---
kind: "section"
citation: "21 C.F.R. § 520.443"
title: "21"
number: "520.443"
heading: "Chlortetracycline tablets and boluses."
url: "https://uscodex.org/cfr/21/520.443"
---

# §520.443. Chlortetracycline tablets and boluses.

- (a) **Specifications.** Each tablet contains 25 milligrams (mg) chlortetracycline hydrochloride; each bolus contains 250 or 500 mg chlortetracycline hydrochloride.
- (b) **Sponsors.** See sponsors in [§ 510.600(c)](/cfr/21/510.600.md?p=c) of this chapter for use as in [paragraph (d)](#d) of this section.
  - (1) **No.** 069043 for use of a 250-mg bolus as in [paragraph (d)(1)](#d-1) of this section.
  - (2) **No.** 016592 for use of a 25-mg tablet as in [paragraph (d)(2)](#d-2) of this section.
  - (3) **No.** 016592 for use of a 500-mg bolus as in [paragraph (d)(3)](#d-3) of this section.
- (c) **Related tolerances.** See [§ 556.150](/cfr/21/556.150.md) of this chapter.
- (d) **Conditions of use in calves—**
  - (1) **Amount.** One 250 milligram bolus per 50 pounds of body weight twice a day for 3 to 5 days.
    - (i) **Indications for use.** Treatment of bacterial enteritis (scours) caused by Escherichia coli and bacterial pneumonia associated with Pasteurella spp., Klesbsiella spp., and Haemophilus spp.
    - (ii) **Limitations.** Administer bolus directly by mouth or crush and dissolve in milk or water for drenching or bucket feeding. Do not use for more than 5 days. Do not administer within 24 hours of slaughter. Federal law restricts this drug to use by or on the order of a licensed veterinarian.
  - (2) **Amount.** One 25 milligram tablet for each 5 pounds of body weight every 12 hours daily for 3 to 5 days.
    - (i) **Indications for use.** Control and treatment of bacterial enteritis (scours) caused by E. coli and Salmonella spp. And bacterial pneumonia associated with Pasteurella spp., Haemophilus spp., and Klebsiella spp., susceptible to chlortetracycline.
    - (ii) **Limitations.** Administer tablet directly by mouth or crush and dissolve in water for drenching; if no improvement is noted after 3 days of treatment, consult a veterinarian; do not use for more than 5 days; when feeding milk or milk replacer, administration 1 hour before or 2 hours after feeding; do not administer within 24 hours of slaughter. Federal law restricts this drug to use by or on the order of a licensed veterinarian.
  - (3) **Amount.** One 500 milligram bolus per 100 pounds of body weight twice a day for 3 to 5 days.
    - (i) **Indications for use.** Treatment of bacterial enteritis (scours) caused by E. coli and Salmonella spp., and bacterial pneumonia associated with Pasteurella spp., Haemophilus spp., and Klebsiella spp., susceptible to chlortetracycline.
    - (ii) **Limitations.** Do not use for more than 5 days. Do not administer within 24 hours of slaughter. Federal law restricts this drug to use by or on the order of a licensed veterinarian.

## Notes

### Amendments

[57 FR 37325, Aug. 18, 1992, as amended at 67 FR 78355, Dec. 24, 2002. Redesignated and amended at 76 FR 49649, Aug. 11, 2011; 78 FR 21059, Apr. 9, 2013; 81 FR 17607, Mar. 30, 2016; 88 FR 16547, Mar. 20, 2023; 88 FR 27698, May 3, 2023; 88 FR 55563, Aug. 16, 2023]

### Authority

Authority: 21 U.S.C. 360b.

### Source

Source: 40 FR 13838, Mar. 27, 1975, unless otherwise noted.

### Amendments

[57 FR 37325, Aug. 18, 1992, as amended at 67 FR 78355, Dec. 24, 2002. Redesignated and amended at 76 FR 49649, Aug. 11, 2011; 78 FR 21059, Apr. 9, 2013; 81 FR 17607, Mar. 30, 2016; 88 FR 16547, Mar. 20, 2023; 88 FR 27698, May 3, 2023; 88 FR 55563, Aug. 16, 2023]