SEC Form 4

FORM 4		UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934 or Section 30(h) of the Investment Company Act of 1940	OMB APPROVAL OMB Number: 3235-0287 Estimated average burden hours per response: 0.5
	Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

1. Name and Address of Reporting Person* SIGMA TAU INTERNATIONAL SA (Last) (First) (Middle) 18 AVENUE DE LA PORTE NEUVE (Street) LUXEMBOURG N4 L-2227 (City) (State) (Zip)	2. Issuer Name and Ticker or Trading Symbol QUESTCOR PHARMACEUTICALS INC [ QSC ]	5. Relationship of Reporting Person(s) to Issuer (Check all applicable) Director X 10% Owner Officer (give title below) Other (specify below)
	3. Date of Earliest Transaction (Month/Day/Year) 04/15/2005
	4. If Amendment, Date of Original Filed (Month/Day/Year)	6. Individual or Joint/Group Filing (Check Applicable Line) Form filed by One Reporting Person X Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Common Stock, no par value per share								8,643,397	D
Common Stock, no par value per share								1,756,781	I	Shares directly held by Claudio Cavazza.(1)
Common Stock, no par value per share								1,756,782	I	Shares directly held by Paolo Cavazza.(1)
Common Stock, no par value per share								759,493	I	Shares directly held by Defiante Farmaceutica L.d.A.(1)
Common Stock, no par value per share								549,100	I	Shares directly held by Aptafin S.p.A.(1)
Common Stock, no par value per share								100,000	I	Shares directly held by Chaumiere - Consultadoria & Servicos SDC Unipessoal LDA.(1)
Common Stock, no par value per share	04/15/2005		J(2)		1,265,822	D	(2)	0	I	Shares underlying the 8% Convertible Debenture held by Defiante Farmaceutica L.d.A.(1)

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
8% Convertible Debenture	$1.58	04/15/2005		J(4)			$2,000,000	(3)	04/15/2005	Common Stock, no par value per share	1,265,822	$2,000,000	$0	I	The 8% Convertible Debenture was directly held by Defiante Farmaceutica L.d.A.(1)

1. Name and Address of Reporting Person* SIGMA TAU INTERNATIONAL SA (Last) (First) (Middle) 18 AVENUE DE LA PORTE NEUVE (Street) LUXEMBOURG N4 L-2227 (City) (State) (Zip)

1. Name and Address of Reporting Person* SIGMA TAU FINANZIARIA SPA (Last) (First) (Middle) VIA SUDAFRICA 20 144 (Street) ROME ITALY (City) (State) (Zip)

1. Name and Address of Reporting Person* DEFIANTE FARMACEUTICA LDA (Last) (First) (Middle) RUA DOS FERREIROS,260 (Street) FUNCHAL MADEIRA S1 9000-082 (City) (State) (Zip)

1. Name and Address of Reporting Person* APTAFIN S P A (Last) (First) (Middle) VIALE SHAKESPEARE 47 (Street) ROME L6 00144 (City) (State) (Zip)

1. Name and Address of Reporting Person* CAVAZZA CLAUDIO (Last) (First) (Middle) VIA SUDAFRICA 20 (Street) ROME ITALY L6 00000 (City) (State) (Zip)

1. Name and Address of Reporting Person* CAVAZZA PAOLO (Last) (First) (Middle) VIA TESSERETE, 10 (Street) LUGANO V8 V8 (City) (State) (Zip)

Explanation of Responses:

1. Sigma-Tau Finanziaria S.p.A. owns 100% of the capital stock of Sigma-Tau International S.A. (f/k/a Sigma-Tau Finance Holding S.A.) and 58% of the capital stock of Defiante Farmaceutica L.d.A. Sigma-Tau International S.A. owns 42% of the capital stock of Defiante Farmaceutica L.d.A. Claudio Cavazza owns, directly and indirectly, 60% of Sigma-Tau Finanziaria S.p.A. and Paolo Cavazza owns, directly and indirectly, 40% of Sigma-Tau Finanziaria S.p.A. Paolo Cavazza also owns, directly and indirectly, 100% of Aptafin S.p.A. Aptafin S.p.A. owns, directly and indirectly, 100% of Chaumiere - Consultadoria & Servicos SDC Unipessoal LDA.

2. The shares were underlying the 8% Convertible Debenture held by Defiante Farmaceutica L.d.A., which matured on April 15, 2005.

3. The 8% Convertible Debenture held by Defiante Farmaceutica L.d.A. was convertible into Common Stock, no par value per share, at any time prior to the maturity date of April 15, 2005.

4. The 8% Convertible Debenture matured on April 15, 2005. Questcor Pharmaceuticals Inc. has advised Defiante Farmaceutica L.d.A. that the debenture will be repaid in full.

	Maurizio Terenzi, Attorney-in-fact for Sigma-Tau International S.A.	04/19/2005
	Maurizio Terenzi, Attorney-in-fact for Sigma-Tau Finanziaria S.p.A.	04/19/2005
	Maurizio Terenzi, Attorney-in-fact for Defiante Farmaceutica L.D.A.	04/19/2005
	Maurizio Terenzi, Attorney-in-fact for Aptafin S.p.A.	04/19/2005
	Maurizio Terenzi, Attorney-in-fact for Chaumiere - Consultadoria & Servicos SDC Unipessoal LDA	04/19/2005
	Maurizio Terenzi, Attorney-in-fact for Claudio Cavazza	04/19/2005
	Maurizio Terenzi, Attorney-in-fact for Paolo Cavazza	04/19/2005
	** Signature of Reporting Person	Date
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