Animal & Veterinary

NADA 039-417 Deccox® - supplemental approval (April 12, 1991)





Rhone-Poulenc, Inc.
500 Northridge Road, Suite 620
Atlanta, Georgia 30350

Generic Name:

decoquinate, Type A medicated article.

Trade Name:


Marketing Status:

Over the Counter (OTC)

Effect of Supplement:

This supplement extends to non-ruminating calves the claim for the prevention of coccidiosis.


For the prevention of coccidiosis in non-ruminating and ruminating calves and cattle caused by E. bovis and E. zurnii.




Type A Medicated Article.






Thoroughly mix Deccox® into the ration at a rate to provide decoquinate at a daily dose of 22.7 mg/100 lb. (0.5 mg/kg) of body weight. Feed for at least 28 days during periods of coccidiosis exposure or when experience indicates that coccidiosis is likely to be a hazard.


The original approval for the use of decoquinate in ruminating calves and cattle was published at 41 FR 53003 12/3/76. Effectiveness data from the original approval remain adequate for this class of calves. Ruminating cattle were selected as the target class of cattle due to the potential compromise of efficacy by the biological flora in the rumen, dilution of drug by the large volume of feed and water in the rumen, and other pharmacodynamic activities of the rumen.


The original approval for the use of decoquinate in ruminating calves and cattle was published at 41 FR 53003 12/3/76. Target animal safety data from the original approval remain adequate for this class of calves.


  1. Toxicity Data and Tolerances

    The toxicity data in NADA 039-417 support the tolerances for residues of decoquinate found in 21 CFR 556.170. These tolerances are 2 ppm for edible tissues other than muscle and 1 ppm for muscle.

  2. Total Residue and Metabolism Data

    Previous total residue C14 studies submitted under NADA 039-417 for ruminating cattle medicated with approximately 5 mg/kg (10x) for 7 days resulted in the following total residues:

    Fat--1.10 ppm
    Liver--0.94 ppm
    Kidney--0.36 ppm
    Muscle--0.18 ppm

    These levels are substantially lower than the established tolerances. For that reason, and in light of the limited metabolism of decoquinate, the total residues obtained at the 10x dose, and an adequate margin of safety weighed against the differences in metabolism that may occur in non-ruminating animals, additional metabolism studies were not required.

  3. Residue Depletion Study

    Decoquinate residues were determined in 8 non-ruminating calves treated with decoquinate (0.5 mg/kg) in milk replacer for 28 days. All the tissue samples contained levels of decoquinate below 0.5 ppm. The range of values for each tissue group is shown below.

    muscle--0.08 - 0.15 ppm
    liver--0.11 - 0.30 ppm
    kidney--0.14 - 0.30 ppm

    Fat was not analyzed due to insufficient sample being available. The results of this residue study establish a zero-day withdrawal period for non-ruminating calves treated with 0.5 mg decoquinate/kg body weight.


The data submitted in support of this supplemental NADA satisfy the requirements of section 512 of the Act and demonstrate that Deccox® (decoquinate), when used under its proposed conditions of use, is safe and effective for the labeled indications. The supplement provides for expanding the claim for the use of decoquinate to non- ruminating calves for the prevention of coccidiosis caused by E. bovis and E. zurnii.

Decoquinate for use in food-producing animals is an over-the-counter product. Accurate diagnosis can be made with a reasonable degree of certainty by the layman, and the conditions for use prescribed on the labeling are likely to be followed in practice. Therefore, the Center for Veterinary Medicine has concluded that this product should remain under over-the-counter marketing status.

Under FDA's regulation concerning approval of supplemental applications (21 CFR 514.106(b)(2)(vi)) this is a Category II change because the claim was expanded for the use of decoquinate in non-ruminating calves to prevent coccidiosis caused by E. bovis and E. zurnii. The approval of this supplement neither poses an increased human risk from exposure to the drug nor alters the condition of the drug's safety in non-ruminating and ruminating calves. Thus, a re-evaluation of the data in the parent NADA was not required.

The approved decoquinate premix is codified in 21 CFR 558.195 as a Type A medicated article for use in broiler chickens, cattle, ruminating calves and goats for the prevention of coccidiosis. The tolerance is codified in section 21 CFR 556.170 and is established at 2 ppm in tissues other than skeletal muscle and 1 ppm in skeletal muscle for negligible residues of decoquinate in the edible tissues of cattle and goats. Withdrawal before slaughter is not required.

Under Section 512(c)(2)(F)(iii) of the Federal Food, Drug and Cosmetic Act [21 U.S.C. 360b(c)(2)(F)(iii)], this supplemental approval does not qualify for exclusivity because neither new clinical or field investigations nor human food safety studies (other than bioequivalence or residue studies) were essential to the approval.


Copies of applicable labels may be obtained by writing to the:

Food and Drug Administration
Freedom of Information Staff (HFI-35)
5600 Fishers Lane
Rockville, MD 20857

Or requests may be sent via fax to: (301) 443-1726. If there are problems sending a fax, call (301) 443-2414.

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