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U.S. Department of Health and Human Services

Animal & Veterinary

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NADA 100-901 Pfichlor 100S Milk Replacer Type A Medicated Article - supplemental approval (January 27, 1998)

Approval Date: January 27, 1998

I. GENERAL INFORMATION

NADA100-901
Sponsor:Hoffmann-LaRoche Inc.
Nutley, NJ 07110
Generic Name:chlortetracycline pre-mix
Trade Name:Pfichlor 100S Milk Replacer Type A Medicated Article
Marketing Status:Over the Counter (OTC)
Effect of Supplement:Category II change

 

II. INDICATIONS FOR USE

See below

 

III. DOSAGE

A. DOSAGE FORM: Tablets

B. ROUTE OF ADMINISTRATION: Oral

C. RECOMMENDED DOSAGES:

DosagesIndication for use
0.1 mg/pound body weight dailyCalves(up to 250 lbs.): For an increased rate of weight gain and improved feed efficiency.
25-70 mg/head/dayCalves(250-400 lbs.): For an increased rate of weight gain and improved feed efficiency.
WARNING Zero-day withdrawal period
10 mg/pound body weight dailyFor calves: Treatment of bacterial enteritis caused by Escherichiacoli.
Treat for not more than 5 days

WARNING
Withdraw 10 days prior to slaughter.

WARNING
A WITHDRAWAL PERIOD HAS NOT BEEN ESTABLISHED FOR THIS PRODUCT IN PRE-RUMINATING CALVES. DO NOT USE IN CALVES TO BE PROCESSED FOR VEAL.

 

IV. EFFECTIVENESS

The drug was the subject of National Academy of Science/National Research Council (NAS/NRC) reports which were published in the FEDERAL REGISTER of July 21, 1970 (35 FR 11647). The Academy evaluated these products as probably effective for growth promotion and feed efficiency and the treatment of animal diseases caused by pathogens sensitive to chlortetracycline.

The Academy states that:

  1. Claims made regarding "for prevention of" or "to prevent" should be replaced with "as an aid in the control of" or "to aid in the control of";
  2. claims for growth promotion or stimulation are disallowed and claims for faster gains and/or feed efficiency should be stated as "may result in faster gains and/or improved feed efficiency under appropriate conditions";
  3. each disease claim should be properly qualified as "appropriate for use in (name of disease) caused by pathogens sensitive to (name of drug) "; if the disease cannot be so qualified the claim must be dropped;
  4. claims pertaining to egg production and hatchability should be changed to "May aid in maintaining egg production and hatchability, under appropriate conditions, by controlling pathogenic microorganisms";
  5. the labels should warn that treated animals must actually consume enough medicated water or medicated feed to provide a therapeutic dosage under the conditions that prevail and, as a precaution, state the desired oral dose per unit of animal weight per day for each species as a guide to effective usage of the preparation in drinking water or feed: and
  6. effective blood levels are required for each recommended dosage.

The Food and Drug Administration concurs with the Academy's findings, interpreting the phrase "...cannot be so qualified..." in paragraph (3) to mean "...is not supported by adequate data..." (See Fed. Reg. vol. 35, No. 140-Tues., July 21, 1970). FDA proceeded to review all available data relating to the effectiveness of products subject to NADA 100-901 to determine which label claims were supported by the requisite proof of effectiveness. That review resulted in a letter to the sponsor dated April 20, 1992, in which the agency stated that it had concluded that such data supported effectiveness only for the control and treatment of certain bacterial diseases susceptible to chlortetracycline hydrochloride in calves, and for increased rate of weight gain and improved feed efficiency in calves.

Thereafter, the sponsor complied with the evaluation of NAS/NRC and FDA's conclusions in the following manner:

  1. Appropriate oral doses for all the allowable species and claims based on milligrams per unit of body weight or grams per ton are on the current labels.
  2. Each disease claim on the label has been properly qualified with the appropriate genus and species of bacteria susceptible to chlortetracycline hydrochloride. Disease claims which were not so qualified have been deleted.
  3. Claims made for prevention have been revised to read "Control of..." where appropriate.

 

V. ANIMAL SAFETY

No further safety data are required.

 

VI. HUMAN FOOD SAFETY

The NAS/NRC evaluation of the drug is concerned only with the effectiveness and safety of the drug for the treated animal. FDA's approval of the supplemental application does not involve reevaluation or reaffirmation of the human food safety data in the parent application. The tolerances for residues of chlortetracycline are codified at 21 CFR 556.150.

 

VII. AGENCY CONCLUSIONS

This supplemental NADA satisfies the requirements of section 512 of the Act and demonstrates that PFICHLOR 100S Type A Medicated Article when used under its proposed conditions of use, is safe and effective for the labeled indications. The approval provides for use of PFICHLOR 100S Type A Medicated Article for the control and treatment of specific diseases in calves, and for increased rate of weight gain and improved feed efficiency in calves.

The "probably effective" finding of the NAS/NRC regarding chlortetracycline hydrochloride which was published in the FEDERAL REGISTER of July 21, 1970, was subsequently reviewed by FDA, resulting in the upgrade to "effective" status with respect to the claims noted in the paragraphs above. The firm submitted revised labeling to conform and, therefore, this supplemental NADA complies with the NAS/NRC evaluation and FDA's conclusions.

When NADA 100-901 was reviewed under NAS/NRC/DESI program, it was an over-the-counter product and this marketing status remains unchanged. Other Chlortetracycline Type A Medicated Articles for use in food-producing animals are also currently on the market as over-the-counter products. Therefore, the Center for Veterinary Medicine has concluded that this product should retain over-the-counter marketing status.

Under the Center's supplemental approval policy (21 CFR 514.106(b)(2)), this is a Category II change. The approval of this change is not expected to have any adverse effect on the safety or effectiveness of this new animal drug and, therefore, did not require a re-evaluation of the human food or target animal safety data in the parent application.

Under section 512(c)(2)(F)(iii) of the FFDCA, this approval for food producing animals does not qualify for marketing exclusivity because the supplemental application does not contain substantial evidence of the effectiveness of the drug involved, any studies of animal safety, or, in the case of food producing animals, human food safety studies (other than bioequivalency or residue studies) required for the approval and conducted or sponsored by the applicant.

 

VIII. LABELING (Attached)

  1. PFICHLOR 100S

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.