
[Federal Register Volume 78, Number 205 (Wednesday, October 23, 2013)]
[Notices]
[Page 63228]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2013-24781]



[[Page 63228]]

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DEPARTMENT OF HEALTH AND HUMAN SERVICES

Food and Drug Administration

[Docket No. FDA-2013-P-0671]


Determination That PARAFLEX (Chlorzoxazone) Tablets, 250 
Milligrams, Was Not Withdrawn From Sale for Reasons of Safety or 
Effectiveness

AGENCY: Food and Drug Administration, HHS.

ACTION: Notice.

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SUMMARY: The Food and Drug Administration (FDA) has determined that 
PARAFLEX (Chlorzoxazone) Tablets, 250 milligrams (mg), was not 
withdrawn from sale for reasons of safety or effectiveness. This 
determination will allow FDA to approve abbreviated new drug 
applications (ANDAs) for PARAFLEX (Chlorzoxazone) Tablets, 250 mg, if 
all other legal and regulatory requirements are met.

FOR FURTHER INFORMATION CONTACT: Kathy Schreier, Center for Drug 
Evaluation and Research, Food and Drug Administration, 10903 New 
Hampshire Ave., Bldg. 51, rm. 6252, Silver Spring, MD 20993-0002, 301-
796-3432.

SUPPLEMENTARY INFORMATION: In 1984, Congress enacted the Drug Price 
Competition and Patent Term Restoration Act of 1984 (Pub. L. 98-417) 
(the 1984 amendments), which authorized the approval of duplicate 
versions of drug products under an ANDA procedure. ANDA applicants 
must, with certain exceptions, show that the drug for which they are 
seeking approval contains the same active ingredient in the same 
strength and dosage form as the ``listed drug,'' which is a version of 
the drug that was previously approved. ANDA applicants do not have to 
repeat the extensive clinical testing otherwise necessary to gain 
approval of a new drug application (NDA).
    The 1984 amendments include what is now section 505(j)(7) of the 
Federal Food, Drug, and Cosmetic Act (21 U.S.C. 355(j)(7)), which 
requires FDA to publish a list of all approved drugs. FDA publishes 
this list as part of the ``Approved Drug Products With Therapeutic 
Equivalence Evaluations,'' which is known generally as the ``Orange 
Book.'' Under FDA regulations, drugs are removed from the list if the 
Agency withdraws or suspends approval of the drug's NDA or ANDA for 
reasons of safety or effectiveness or if FDA determines that the listed 
drug was withdrawn from sale for reasons of safety or effectiveness (21 
CFR 314.162).
    A person may petition the Agency to determine, or the Agency may 
determine on its own initiative, whether a listed drug was withdrawn 
from sale for reasons of safety or effectiveness. This determination 
may be made at any time after the drug has been withdrawn from sale, 
but must be made prior to approving an ANDA that refers to the listed 
drug (Sec.  314.161 (21 CFR 314.161)). FDA may not approve an ANDA that 
does not refer to a listed drug.
    PARAFLEX (Chlorzoxazone) Tablets, 250 mg, is the subject of NDA 11-
300, held by Ortho McNeil Pharm, and was initially approved on December 
12, 1958. PARAFLEX is indicated as an adjunct to rest, physical 
therapy, and other measures for the relief of discomfort associated 
with acute, painful musculoskeletal conditions.
    In letters dated April 11, 1997, and April 22, 1997, a former NDA 
holder, The R.W. Johnson Pharmaceutical Research Institute, notified 
FDA that PARAFLEX (Chlorzoxazone) Tablets, 250 mg, had been 
discontinued and requested withdrawal of NDA 11-300, and FDA moved the 
drug product to the ``Discontinued Drug Product List'' section of the 
Orange Book. In the Federal Register of September 25, 1997 (62 FR 
50387), FDA announced that it was withdrawing approval of NDA 11-300, 
effective September 25, 1997.
    Lachman Consultant Services, Inc., submitted a citizen petition 
dated June 4, 2013 (Docket No. FDA-2013-P-0671), under 21 CFR 10.30, 
requesting that the Agency determine whether PARAFLEX (Chlorzoxazone) 
Tablets, 250 mg, was withdrawn from sale for reasons of safety or 
effectiveness.
    After considering the citizen petition and reviewing Agency records 
and based on the information we have at this time, FDA has determined 
under Sec.  314.161 that PARAFLEX (Chlorzoxazone) Tablets, 250 mg, was 
not withdrawn for reasons of safety or effectiveness. The petitioner 
has identified no data or other information suggesting that PARAFLEX 
(Chlorzoxazone) Tablets, 250 mg, was withdrawn for reasons of safety or 
effectiveness. We have carefully reviewed our files for records 
concerning the withdrawal of PARAFLEX (Chlorzoxazone) Tablets, 250 mg, 
from sale. We have also independently evaluated relevant literature and 
data for possible postmarketing adverse events. We have found no 
information that would indicate that this product was withdrawn from 
sale for reasons of safety or effectiveness.
    Accordingly, the Agency will continue to list PARAFLEX 
(Chlorzoxazone) Tablets, 250 mg, in the ``Discontinued Drug Product 
List'' section of the Orange Book. The ``Discontinued Drug Product 
List'' delineates, among other items, drug products that have been 
discontinued from marketing for reasons other than safety or 
effectiveness. ANDAs that refer to PARAFLEX (Chlorzoxazone) Tablets, 
250 mg, may be approved by the Agency as long as they meet all other 
legal and regulatory requirements for the approval of ANDAs. If FDA 
determines that labeling for this drug product should be revised to 
meet current standards, the Agency will advise ANDA applicants to 
submit such labeling.

    Dated: October 3, 2013.
Leslie Kux,
Assistant Commissioner for Policy.
[FR Doc. 2013-24781 Filed 10-22-13; 8:45 am]
BILLING CODE 4160-01-P


