Exhibit 5.1


[MINTZ LEVIN LOGO]                                          One Financial Center
                                                                Boston, MA 02111
                                                                    617-542-6000
                                                                617-542-2241 fax
                                                                   www.mintz.com



June 23, 2006

King Pharmaceuticals, Inc.
501 Fifth Street
Bristol, Tennessee  37620

King Pharmaceuticals Research and Development, Inc.
4000 CentreGreen Way
Cary, North Carolina  27513

Meridian Medical Technologies, Inc.
6350 Stevens Forest Road
Suite 301
Columbia, Maryland  21046

Monarch Pharmaceuticals, Inc.
501 Fifth Street
Bristol, Tennessee  37620

Parkedale Pharmaceuticals, Inc.
870 Parkedale Road
Rochester, Michigan  48307

King Pharmaceuticals of Nevada, Inc.
501 Fifth Street
Bristol, Tennessee  37620


Ladies and Gentlemen:

We have acted as counsel to King Pharmaceuticals, Inc., a Tennessee corporation
(the "COMPANY"), King Pharmaceuticals Research and Development, Inc., a Delaware
corporation ("KING RESEARCH AND DEVELOPMENT"), Meridian Medical Technologies,
Inc., a Delaware corporation ("MERIDIAN MEDICAL"), Monarch Pharmaceuticals,
Inc., a Tennessee corporation ("MONARCH"), Parkedale Pharmaceuticals, Inc., a
Michigan corporation ("PARKEDALE") and King Pharmaceuticals of Nevada, Inc., a
Nevada corporation ("KING NEVADA"), in connection with the preparation and
filing with the Securities and Exchange Commission (the "COMMISSION") of a
Registration Statement on Form S-3 (the "REGISTRATION STATEMENT"), pursuant to
which (i) the Company is registering under the Securities Act of 1933, as
amended (the "SECURITIES ACt"), (A) $400,000,000 aggregate principal amount of
its 1 1/4% Convertible Senior Notes due 2026 (the "Notes") and (B) shares of its
common stock, no par value per share, into which the Notes are




            
               MINTZ, LEVIN, COHN, FERRIS, GLOVSKY AND POPEO, P.C.

BOSTON | WASHINGTON | NEW YORK | STAMFORD | LOS ANGELES | PALO ALTO | SAN DIEGO | LONDON





MINTZ, LEVIN, COHN, FERRIS, GLOVSKY AND POPEO, P.C.

June 23, 2006
Page 2


convertible (the "SHARES"); (ii) King Research and Development is registering
under the Securities Act subordinated guarantees of the Notes (the "KING
RESEARCH AND DEVELOPMENT GUARANTEES"); (iii) Meridian Medical is registering
under the Securities Act subordinated guarantees of the Notes (the "MERIDIAN
MEDICAL GUARANTEES"); (iv) Monarch is registering under the Securities Act
subordinated guarantees of the Notes (the "MONARCH GUARANTEES"); (v) Parkedale
is registering under the Securities Act subordinated guarantees of the Notes
(the "PARKEDALE GUARANTEES"); and (vi) King Nevada is registering under the
Securities Act subordinated guarantees of the Notes (the "KING NEVADA
GUARANTEES" and, together with the Notes, the Shares, the King Research and
Development Guarantees, the Meridian Medical Guarantees, the Monarch Guarantees
and the Parkedale Guarantees, the "SECURITIES"), all of which may be sold by the
selling security holders named in the prospectus included in the Registration
Statement (the "SELLING SECURITY HOLDERS") from time to time on a delayed or
continuous basis pursuant to Rule 415 under the Securities Act.

         In connection with this opinion, we have examined (a) the Second
Amended and Restated Charter, as amended, and the Amended and Restated Bylaws of
the Company, both as currently in effect; (b) the Certificate of Incorporation,
as amended, and the Bylaws of King Research and Development, both as currently
in effect; (c) the Restated Certificate of Incorporation, as amended, and the
Bylaws of Meridian Medical, both as currently in effect; (d) the Amended and
Restated Charter, as amended, and the Bylaws of Monarch, both as currently in
effect; (e) the Articles of Incorporation, as amended, and the Bylaws of
Parkedale, both as currently in effect; (f) the Articles of Incorporation and
the Code of Bylaws of King Nevada, both as currently in effect; (g) such other
records of the corporate proceedings of, and such certificates of the officers
of, the Company, King Research and Development, Meridian Medical, Monarch,
Parkedale and King Nevada as we have deemed relevant; and (h) the Registration
Statement and the exhibits thereto.

         In our examination, we have assumed the genuineness of all signatures,
the legal capacity of natural persons, the authenticity of all documents
submitted to us as originals, the conformity to original documents of all
documents submitted to us as certified or photostatic copies and the
authenticity of the originals of such copies.

         No opinion is expressed herein with respect to any matter which is
determined by the law of any jurisdiction except the federal laws of the United
States of America, the laws of the Commonwealth of Massachusetts, the General
Corporation Law of the State of Delaware (including the applicable provisions of
the Delaware Constitution and the reported judicial decisions interpreting such
laws) and the laws of the State of New York, and we express no opinion with
respect to the laws of any other jurisdiction. The opinions expressed herein are
based upon currently existing statutes, rules, regulations and judicial
decisions and are rendered as of the date hereof, and we disclaim any obligation
to advise you of any change in the foregoing sources of law or subsequent
developments in the law or changes in facts or circumstances which might affect
any matters or opinions set forth herein after the Registration Statement has
been declared effective by the Commission. We are opining only as to the matters



MINTZ, LEVIN, COHN, FERRIS, GLOVSKY AND POPEO, P.C.

June 23, 2006
Page 3


expressly set forth herein, and no opinion should be inferred as to other
matters. In addition, we are not passing upon any matters relating to patents or
trademarks, or federal or state regulation or any legal or governmental
proceedings pertaining to the same. No opinion is expressed herein with respect
to the qualification of the Securities under the securities or blue sky laws of
any state or foreign jurisdiction. The Securities may be offered and sold by the
Selling Security Holders from time to time on a delayed or continuous basis, but
this opinion is limited to the laws, including the rules and regulations
thereunder, as in effect on the date hereof.

         Based upon the foregoing, provided no stop order shall have been issued
by the Commission relating thereto, we are of the opinion that:

         1.       the Notes, when sold by the Selling Security Holders pursuant
                  to the Registration Statement (including any amendment and any
                  prospectus supplement relating thereto), will constitute
                  legal, valid and binding obligations of the Company,
                  enforceable against the Company in accordance with their
                  terms, subject to applicable bankruptcy, insolvency,
                  fraudulent conveyance, reorganization, moratorium and similar
                  laws affecting creditors' rights and remedies generally, and
                  subject, as to enforceability, to general principles of
                  equity, including principles of commercial reasonableness,
                  good faith and fair dealing (regardless of whether enforcement
                  is sought in a proceeding at law or in equity);

         2.       the King Research and Development Guarantees, when sold along
                  with the Notes by the Selling Security Holders pursuant to the
                  Registration Statement (including any amendment and any
                  prospectus supplement relating thereto), will constitute
                  legal, valid and binding obligations of King Research and
                  Development, enforceable against King Research and Development
                  in accordance with their terms, subject to applicable
                  bankruptcy, insolvency, fraudulent conveyance, reorganization,
                  moratorium and similar laws affecting creditors' rights and
                  remedies generally, and subject, as to enforceability, to
                  general principles of equity, including principles of
                  commercial reasonableness, good faith and fair dealing
                  (regardless of whether enforcement is sought in a proceeding
                  at law or in equity);

         3.       the Meridian Medical Guarantees, when sold along with the
                  Notes by the Selling Security Holders pursuant to the
                  Registration Statement (including any amendment and any
                  prospectus supplement relating thereto), will constitute
                  legal, valid and binding obligations of Meridian Medical,
                  enforceable against Meridian Medical in accordance with their
                  terms, subject to applicable bankruptcy, insolvency,
                  fraudulent conveyance, reorganization, moratorium and similar
                  laws affecting creditors' rights and remedies generally, and
                  subject, as to enforceability, to general principles of
                  equity, including principles of commercial reasonableness,
                  good faith and fair dealing (regardless of whether enforcement
                  is sought in a proceeding at law or in equity);



MINTZ, LEVIN, COHN, FERRIS, GLOVSKY AND POPEO, P.C.

June 23, 2006
Page 4


         4.       the Monarch Guarantees, when sold along with the Notes by the
                  Selling Security Holders pursuant to the Registration
                  Statement (including any amendment and any prospectus
                  supplement relating thereto), will constitute legal, valid and
                  binding obligations of Monarch, enforceable against Monarch in
                  accordance with their terms, subject to applicable bankruptcy,
                  insolvency, fraudulent conveyance, reorganization, moratorium
                  and similar laws affecting creditors' rights and remedies
                  generally, and subject, as to enforceability, to general
                  principles of equity, including principles of commercial
                  reasonableness, good faith and fair dealing (regardless of
                  whether enforcement is sought in a proceeding at law or in
                  equity);

         5.       the Parkedale Guarantees, when sold along with the Notes by
                  the Selling Security Holders pursuant to the Registration
                  Statement (including any amendment and any prospectus
                  supplement relating thereto), will constitute legal, valid and
                  binding obligations of Parkedale, enforceable against
                  Parkedale in accordance with their terms, subject to
                  applicable bankruptcy, insolvency, fraudulent conveyance,
                  reorganization, moratorium and similar laws affecting
                  creditors' rights and remedies generally, and subject, as to
                  enforceability, to general principles of equity, including
                  principles of commercial reasonableness, good faith and fair
                  dealing (regardless of whether enforcement is sought in a
                  proceeding at law or in equity); and

         6.       the King Nevada Guarantees, when sold along with the Notes by
                  the Selling Security Holders pursuant to the Registration
                  Statement (including any amendment and any prospectus
                  supplement relating thereto), will constitute legal, valid and
                  binding obligations of King Nevada, enforceable against King
                  Nevada in accordance with their terms, subject to applicable
                  bankruptcy, insolvency, fraudulent conveyance, reorganization,
                  moratorium and similar laws affecting creditors' rights and
                  remedies generally, and subject, as to enforceability, to
                  general principles of equity, including principles of
                  commercial reasonableness, good faith and fair dealing
                  (regardless of whether enforcement is sought in a proceeding
                  at law or in equity).

         It is understood that this opinion is to be used only in connection
with the offer and sale of the Securities while the Registration Statement is in
effect.




MINTZ, LEVIN, COHN, FERRIS, GLOVSKY AND POPEO, P.C.

June 23, 2006
Page 5



         We hereby consent to (i) the reference to this firm under the caption
"Legal Matters" in the prospectus forming a part of the Registration Statement
and (ii) the filing of this opinion as an exhibit to the Registration Statement.
In giving such consent, we do not hereby admit that we are in the category of
persons whose consent is required under Section 7 of the Securities Act or the
rules and regulations of the Commission.


                                  Very truly yours,

                                  /s/ Mintz, Levin, Cohn, Ferris,
                                         Glovsky and Popeo, P.C.

                                  MINTZ, LEVIN, COHN, FERRIS,
                                    GLOVSKY AND POPEO, P.C.