---
kind: "section"
citation: "21 C.F.R. § 558.254"
title: "21"
number: "558.254"
heading: "Famphur."
url: "https://uscodex.org/cfr/21/558.254"
---

# §558.254. Famphur.

- (a) **Specifications.** Type A medicated articles containing 13.2 or 33.3 percent famphur.
- (b) **Sponsor.** See No. 000061 in [§ 510.600(c)](/cfr/21/510.600.md?p=c) of this chapter.
- (c) **Related tolerances.** See [§ 556.273](/cfr/21/556.273.md) of this chapter.
- (d) **Special considerations.** Famphur is a cholinesterase inhibitor. 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.
- (e) **Conditions of use.** It is used in cattle feed as follows:

## Notes

### Amendments

[84 FR 39185, Aug. 9, 2019, as amended at 87 FR 17947, Mar. 29, 2022]

### Authority

Authority: 21 U.S.C. 354, 360b, 360ccc, 360ccc-1, 371.

### Source

Source: 40 FR 13959, Mar. 27, 1975, unless otherwise noted.

### Amendments

[84 FR 39185, Aug. 9, 2019, as amended at 87 FR 17947, Mar. 29, 2022]