Allergan, Inc. 424(b)(3)
 

Filed Pursuant to Rule 424(b)(3)
Registration Statement No. 333-50524

Prospectus Supplement No. 23
to
Prospectus Dated December 8, 2000

ALLERGAN, INC.

Liquid Yield Option™ Notes due 2020
(Zero Coupon — Subordinated)


     The following information supplements, and must be read in connection with, the information contained in the Prospectus, dated December 8, 2000 (the “Prospectus”), of Allergan, Inc., a Delaware corporation. This Prospectus Supplement must be delivered with a copy of the Prospectus. All capitalized terms not otherwise defined herein have the respective meanings ascribed to them in the Prospectus.

     The following information replaces in its entirety the information provided in the Prospectus under the caption “Selling Securityholders.”


Selling Securityholders

     The LYONs were originally issued by us and sold by Merrill Lynch, Pierce, Fenner & Smith Incorporated (the “Initial Purchaser”) in a transaction exempt from the registration requirements of the Securities Act to persons reasonably believed by such Initial Purchaser to be “qualified institutional buyers” (as defined by Rule 144A under the Securities Act). The Selling Securityholders (which term includes their transferees, pledges, donees or successors) may from time to time offer and sell pursuant to this prospectus any and all of the LYONs and common stock.

     Set forth below are the names of each Selling Securityholder, the principal amount of LYONs that may be offered by such Selling Securityholder pursuant to this prospectus and the number of shares of common stock into which such LYONs are convertible. Unless set forth below, none of the Selling Securityholders has had a material relationship with us or any of our predecessors or affiliates within the past three years.

     The following table sets forth certain information received by us on or prior to April 23, 2002. However, any or all of the LYONs or common stock listed below may be offered for sale pursuant to this prospectus by the Selling Securityholders from time to time. Accordingly, no estimate can be given as to the amounts of LYONs or common stock that will be held by the Selling Securityholders upon consummation of any such sales. In addition, the Selling Securityholders identified below may have sold, transferred, or otherwise disposed of all or a portion of their LYONs since the date on which the information regarding their LYONs was provided, in transactions exempt from the registration requirements of the Securities Act.

 


 

                                 
    Aggregate                        
    Principal           Common        
    Amount           Stock   Common
    of LYONs at   Percentage   Owned   Stock
    Maturity that   of LYONs   Prior to   Registered
Name   May Be Sold   Outstanding   Conversion   Hereby(1)

 
 
 
 
1976 Distribution Trust F/B/O A.R. Lauder/Zinterkhoffer
  $ 32,000       *             184  
1976 Distribution Trust F/B/O Jene A. Lauder
    32,000       *             184  
AIB Securities Services
    22,800,000       3.47             131,362  
AIG Soundshore Opportunity Holding Fund Ltd.
    4,250,000       *             24,486  
AIG Soundshore Strategic Holding Fund Ltd.
    4,250,000       *             24,486  
AIG/National Union Fire Insurance
    2,035,000       *             11,725  
Allstate Life Insurance Company
    5,500,000       *       31,000 (2)     31,688  
Aloha Airlines Non-Pilots Pension Trust
    375,000       *             2,161  
Aloha Pilots Retirement Trust
    210,000       *             1,210  
American Fidelity Assurance Company
    200,000       *             1,152  
American Motorist Insurance Company
    1,309,000       *             7,542  
Amerisure Companies/Michigan Mutual Insurance Co.
    550,000       *             3,169  
AmSouth Bank, Custodian for AmSouth Variable Equity Income Fund
    2,180,000       *             12,560  
AmSouth Bank, Custodian for AmSouth Equity Income Fund
    4,900,000       *             28,231  
Arapahoe County Colorado
    111,000       *             640  
Arkansas Teachers Retirement
    9,113,000       1.39             52,505  
Arpeggo Fund, LP
    4,200,000       *             24,198  
Associated Electric & Gas Insurance Services Limited
    1,000,000       *             5,762  
Attorney’s Title Insurance Fund, Inc.
    500,000       *             2,881  
Aventis Pension Master Trust
    385,000       *             2,218  
Banc of America Securities LLC
    500,000       *             2,881  
Bancroft Convertible Fund, Inc.
    815,000       *             4,696  
Bank Austria Cayman Island, Ltd.
    2,500,000       *             14,404  
Baptist Health of South Florida
    482,000       *             2,777  
Bay County PERS
    455,000       *             2,621  
Blue Cross Blue Shield of Florida
    2,000,000       *             11,523  
Boilermaker — Blacksmith Pension Trust
    2,275,000       *             13,107  
Boston Museum of Fine Art
    245,000       *             1,412  
British Virgin Islands Social Security Board
    84,000       *             484  
BS Debt Income Fund — Class A
    25,000       *             144  
C & H Sugar Company, Inc.
    575,000       *             3,313  
CA State Automobile Assn Inter-Insurance
    1,100,000       *             6,338  
CALAMOS® Convertible Fund - CALAMOS® Investment Trust
    3,690,000       *             21,260  
CALAMOS® Convertible Growth and Income Fund — CALAMOS® Investment Trust
    2,370,000       *             13,655  
CALAMOS® Convertible Portfolio - CALAMOS® Advisors Trust
    150,000       *             864  

2


 

                                 
    Aggregate                        
    Principal           Common        
    Amount           Stock   Common
    of LYONs at   Percentage   Owned   Stock
    Maturity that   of LYONs   Prior to   Registered
Name   May Be Sold   Outstanding   Conversion   Hereby(1)

 
 
 
 
CALAMOS® Global Convertible Fund - CALAMOS®
Investment Trust
    500,000       *             2,881  
California State Automobile Inter Insurance
    390,000       *             2,247  
California State Automobile Retirement Pension
    90,000       *             519  
Capital Care, Inc.
    60,000       *             346  
CareFirst of Maryland, Inc.
    275,000       *             1,584  
Charitable Convertible Securities Fund
    380,000       *             2,189  
Charitable Income Fund
    150,000       *             864  
Chrysler Corporation Master Retirement Trust
    2,960,000       *             17,054  
CIBC World Markets International Arbitrage Corp.
    8,000,000       1.22             46,092  
City of Albany Pension Plan
    215,000       *             1,239  
City of Birmingham Retirement & Relief System
    1,800,000       *             10,371  
City of Knoxville Pension System
    520,000       *             2,996  
City University of New York
    271,000       *             1,561  
Clinton Riverside Convertible Portfolio Limited
    3,000,000       *             17,285  
Conseco Annuity Assurance — Multi-bucket Annuity Convertible Bond Fund
    9,000,000       1.37             51,854  
Conseco Fund Group — Convertible Securities Fund
    2,000,000       *             11,523  
Continental Assurance Company
    1,400,000       *             8,066  
Continental Casualty Company
    7,600,000       1.16             43,787  
Credit Suisse First Boston Corporation
    13,663,000       2.08             78,719  
Daimler Chrysler Corporation Emp. #1 Pension Plan DTD 4/1/89
    5,665,000       *             32,639  
DeAm Convertible Arbitrage Fund
    3,500,000       *             20,165  
Delta Air Lines Master Trust (c/o Oaktree Capital
Management, LLC)
    1,065,000       *             6,136  
Delta Airlines Master Trust
    4,280,000       *             24,659  
Deutsche Bank Alex Brown Inc.
    39,000       *             225  
Dorinco Reinsurance Company
    1,500,000       *             8,642  
EB Convertible Securities Fund
    800,000       *             4,609  
Elf Aquitaine
    400,000       *             2,305  
Ellsworth Convertible Growth and Income Fund, Inc.
    815,000       *             4,696  
Engineers Joint Pension Fund
    1,006,000       *             5,796  
Enterprise Convertible Security Fund
    127,000       *             732  
Fidelity Financial Trust:
Fidelity Convertible Securities Fund(3)
    10,800,000       1.64             62,224  
Fidelity Financial Trust:
Fidelity Equity-Income Fund(3)
    18,103,000       2.75             104,300  

3


 

                                 
    Aggregate                        
    Principal           Common        
    Amount           Stock   Common
    of LYONs at   Percentage   Owned   Stock
    Maturity that   of LYONs   Prior to   Registered
Name   May Be Sold   Outstanding   Conversion   Hereby(1)

 
 
 
 
Fidelity Management Trust Company on behalf of accounts
managed by it(4)
    1,097,000       *             6,320  
Field Foundation of Illinois
    40,000       *             230  
Finance Factors Limited
    450,000       *             2,593  
First Republic Bank
    175,000       *             1,008  
Franklin and Marshall College
    375,000       *             2,161  
Free State Health Plan, Inc.
    80,000       *             461  
GE Pension Trust
    2,800,000       *             16,132  
Global Bermuda Limited Partnership
    750,000       *             4,321  
Genesee County Employees’ Retirement System
    475,000       *             2,737  
Goldman Sachs and Company
    23,000,000       3.50             132,515  
Grady Hospital Foundation
    243,000       *             1,400  
Greek Catholic Union
    35,000       *             202  
Greek Catholic Union II
    30,000       *             173  
Group Hospitalization and Medical Services, Inc.
    300,000       *             1,728  
Gryphon Domestic III, LLC
    12,200,000       1.86             70,290  
H.K. Porter Company, Inc.
    60,000       *             346  
Hamilton Partners Limited
    1,000,000       *             5,762  
Hawaiian Airlines Employees Pension Plan — IAM
    170,000       *             979  
Hawaiian Airlines Pension Plan for Salaried Employees
    35,000       *             202  
Hawaiian Airlines Pilots Retirement Plan
    330,000       *             1,901  
HealthNow New York, Inc.
    175,000       *             1,008  
IL Annuity and Insurance Company
    6,000,000       *             34,569  
Independence Blue Cross
    235,000       *             1,354  
ING Barings LLC
    50,000       *             288  
Investcorp-SAM Fund Limited
    13,000,000       1.98             74,900  
Island Insurance Convertible Account
    310,000       *             1,786  
Islands Holdings
    125,000       *             720  
Jackson County Employees’ Retirement System
    375,000       *             2,161  
Jefferies & Co.
    4,000,000       *             23,046  
Julius Baer Multibond Convertbond
    1,250,000       *             7,202  
KBC Financial Products USA, Inc.
    2,000,000       *             11,523  
Kerr McGee Corporation
    1,750,000       *             10,083  
Kettering Medical Center Funded Depreciation Account
    145,000       *             835  
Key Trust Convertible Securities Fund
    160,000       *             922  
Key Trust Fixed Income Fund
    210,000       *             1,210  
Knoxville Utilities Board Retirement System
    335,000       *             1,930  
Lakeshore International Ltd.
    1,750,000       *             10,083  
Lancer Securities Cayman
    1,400,000       *             8,066  
Lehman Brothers Inc.
    54,820,000       8.34             315,845  
Local Universities Support Corporation
    108,000       *             622  

4


 

                                 
    Aggregate                        
    Principal           Common        
    Amount           Stock   Common
    of LYONs at   Percentage   Owned   Stock
    Maturity that   of LYONs   Prior to   Registered
Name   May Be Sold   Outstanding   Conversion   Hereby(1)

 
 
 
 
Louisiana Workers’ Compensation Corporation
    325,000       *             1,872  
Lumberman’s Mutual Casualty
    1,039,000       *             5,986  
Lutheran Brotherhood
    3,000,000       *             17,285  
Lydian Overseas Partners Master Fund
    24,000,000       3.65             138,276  
Macomb County Employees’ Retirement System
    325,000       *             1,872  
McMahan Securities Co. L.P.
    975,000       *             5,617  
Merrill Lynch Insurance Group
    569,000       *             3,278  
Merrill Lynch, Pierce, Fenner & Smith, Inc.(5)
    31,922,000       4.86             183,919  
Merrill Lynch Quantitative Advisors Securities Arbitrage Ltd.
    11,500,000       1.75             66,257  
Morgan Stanley & Co.
    20,000,000       3.04             115,230  
Morgan Stanley Dean Witter Convertible Securities Trust
    3,600,000       *             20,741  
Motion Picture Industry Health Plan — Active Member Fund
    345,000       *             1,988  
Motion Picture Industry Health Plan — Retiree Member Fund
    175,000       *             1,008  
Museum of Fine Arts, Boston
    20,000       *             115  
Nabisco Holdings
    67,000       *             386  
Nalco Chemical Company
    750,000       *             4,321  
Nashville Electric Service
    325,000       *             1,872  
New Orleans Firefighters Pension/Relief Fund
    252,000       *             1,452  
New York Life Insurance and Annuity Corporation
    1,250,000       *             7,202  
New York Life Insurance Company
    11,250,000       1.71             64,817  
Nicholas Applegate Convertible Fund
    3,165,000       *             18,235  
Nicholas Applegate Global Holdings Co. LP
    80,000       *             461  
Nicholas Applegate Investment Grade Convertible
    13,000       *             75  
Norcal Mutual Insurance Company
    400,000       *             2,305  
Occidental Petroleum
    433,000                     2,495  
OCM Convertible Trust
    1,355,000       *             7,807  
Ohio Bureau of Workers Compensation
    302,000       *             1,740  
Oxford, Lord, Abbett & Co.
    2,750,000       *             15,844  
Pacific Life Insurance Company
    2,000,000       *             11,523  
Pacific Specialty (Convertibles)
    850,000       *             4,897  
Palladin Securities
    1,050,000       *             6,050  
Parker/Key Convertible Securities Fund
    180,000       *             1,037  
Parker-Hannifin Corporation
    190,000       *             1,095  
Partner Reinsurance Company Ltd.
    590,000       *             3,399  
Penn Treaty Network American Insurance Company
    460,000       *             2,650  
PGEP III LLC
    1,050,000       *             6,050  
Physicians Life
    791,000       *             4,557  
Physicians’ Reciprocal Insurers Account #7
    2,000,000       *             11,523  
PIMCO Convertible Fund
    5,900,000       *             33,993  

5


 

                                 
    Aggregate                        
    Principal           Common        
    Amount           Stock   Common
    of LYONs at   Percentage   Owned   Stock
    Maturity that   of LYONs   Prior to   Registered
Name   May Be Sold   Outstanding   Conversion   Hereby(1)

 
 
 
 
Port Authority of Allegheny County Retirement and Disability Allowance Plan for the Employees Represented by Local 85 of the Amalgamated Transit Union
    2,520,000       *             14,519  
Potlatch-First Trust Company of St. Paul
    300,000       *             1,728  
PRIM Board
    6,050,000       *             34,857  
ProMutual
    420,000       *             2,420  
Putnam Asset Allocation Funds—Balanced Portfolio
    845,000       *             4,868  
Putnam Asset Allocation Funds—Conservative Portfolio
    510,000       *             2,938  
Putnam Convertible Income—Growth Trust
    7,396,000       1.12             42,612  
Putnam Convertible Opportunities and Income Trust
    280,000       *             1,613  
Quattro Fund, LLC
    1,500,000       *             8,642  
Queens Health Plan
    125,000       *             720  
R2 Investments, LDC
    12,000,000       1.83             69,138  
Radian Guaranty, Inc.
    2,500,000       *             14,404  
Ramius Capital Group Holdings, Ltd.
    700,000       *             4,033  
Raytheon Master Pension Trust
    876,000       *             5,047  
RCG Lattitude Master Fund
    800,000       *             4,609  
Ret Pension Plan of the CA State Automob
    350,000       *             2,017  
Rhapsody Fund LP
    14,600,000       2.22             84,118  
RJR Reynolds
    220,000       *             1,268  
Rockhaven Premier Dividend Fund
    930,000       *             5,358  
Salomon Brothers Asset Management, Inc.
    1,650,000       *             9,506  
Salomon Smith Barney Inc.
    4,000,000       *             23,046  
San Diego City Retirement
    1,973,000       *             11,367  
San Diego County Convertible
    4,250,000       *             24,486  
Screen Actors Guild Pension Convertible
    1,072,000       *             6,176  
Shell Pension Trust
    831,000       *             4,788  
South Dakota Retirement System
    2,000,000       *             11,523  
Southern Farm Bureau Life Insurance
    3,350,000       *             19,301  
SPT
    1,830,000       *             10,544  
Standard Insurance Company
    450,000       *             2,593  
Starvest Combined Portfolio
    2,475,000       *             14,260  
Starvest Managed Portfolio
    200,000       *             1,152  
State Employees’ Retirement Fund of the State of Delaware
    1,495,000       *             8,613  
State of Connecticut Combined Investment Funds
    3,290,000       *             18,955  
State of Maryland Retirement System
    5,923,000       *             34,125  
State of Mississippi Health Care Trust Fund
    1,600,000       *             9,218  
State of Oregon/SAIF Corporation
    14,750,000       2.24             84,982  
Teacher’s Insurance and Annuity Association
    7,000,000       1.06             40,331  
The Class 1c Company
    4,000,000       *             23,046  
The Cockrell Foundation
    125,000       *             720  

6


 

                                 
    Aggregate                        
    Principal           Common        
    Amount           Stock   Common
    of LYONs at   Percentage   Owned   Stock
    Maturity that   of LYONs   Prior to   Registered
Name   May Be Sold   Outstanding   Conversion   Hereby(1)

 
 
 
 
The Dow Chemical Company Employees’ Retirement Plan
    4,550,000       *             26,215  
The Fondren Foundation
    145,000       *             835  
The Grable Foundation
    216,000       *             1,244  
Tribeca Investments LLC
    12,000,000       1.83             69,138  
UBS AG, London Branch
    11,000,000       1.67             63,377  
UBS O’Connor LLC f/b/o UBS Global Equity Arbitrage Master Limited
    7,500,000       1.14             43,211  
UBS Warburg LLC
    61,540,000       9.36             354,563  
Unifi, Inc. Profit Sharing Plan and Trust
    230,000       *             1,325  
United Food and Commercial Workers Local 1262 and Employers Pension Fund
    1,140,000       *             6,568  
University of Rochester
    100,000       *             576  
University of South Florida
    550,000       *             3,169  
University of South Florida Foundation
    80,000       *             461  
Van Kampen Harbor Fund
    13,700,000       2.08       2,635,165 (6)     78,933  
Van Waters & Rogers, Inc. Retirement Plan
    650,000       *             3,745  
Vanguard Convertible Securities Fund, Inc.
    3,725,000       *             21,462  
Victory Capital Management as Trustee for Parker Key/Convertible
    190,000       *               1,095  
Victory Convertible Securities Fund
    580,000       *             3,342  
Victory Invest Quality Bond Fund
    90,000       *             519  
Wake Forest University
    1,867,000       *             10,757  
Writers Guild Convertible
    626,000       *             3,607  
Wyoming State Treasurer
    2,153,000       *             12,405  


*   Less than one percent.
(1)   Assumes conversion of all of the Holder’s LYONs at a conversion rate of 5.7615 shares of common stock per $1,000 principal amount at maturity of the LYONs. However, this conversion rate will be subject to adjustment as described under “Description of the LYONs — Conversion Rights.” As a result, the amount of common stock issuable upon conversion of the LYONs may increase or decrease in the future.
(2)   The Allstate Corporation (“Allstate”) directly and through its subsidiaries currently owns 29,600 shares of Company common stock. The Agents Pension Plan (the “Pension Plan”) currently owns 1,400 shares of Company common stock. The Pension Plan is a qualified ERISA plan that is maintained for the benefit of certain agents of Allstate Insurance Company (“AIC”), a subsidiary of Allstate. The Trustee for the Pension Plan holds title to all Pension Plan investments. Allstate disclaims any interest in securities held in the pension plan trust, although the Investment Committee of the Pension Plan consists of AIC officers. In the course of managing their investment portfolios, AIC and its affiliates may acquire and hold investments that exceed 10% of a class of equity securities of an issuer. The Public Equity Group of the Investment Department of AIC, which has the responsibility for the securities described herein, is not aware of any positions, offices or other material relationships involving AIC or its subsidiaries which are required to be disclosed. However, no independent investigation has been made as to whether there are or may have been any such transactions as a result of insurance activities, investment activities or other groups or divisions or actions with respect to or by such investing companies.

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(3)   This entity is either an investment company or a portfolio of an investment company registered under Section 8 of the Investment Company Act of 1940, as amended, or a private investment account advised by Fidelity Management & Research Company (“FMR Co.”). FMR Co. is a Massachusetts corporation and an investment advisor registered under Section 203 of the Investment Advisers Act of 1940, as amended, and provides investment advisory services to each of such Fidelity entities identified above, and to other registered investment companies and to certain other funds which are generally offered to a limited group of investors. FMR Co. is a wholly-owned subsidiary of FMR Corp. (“FMR”), a Massachusetts corporation. The holdings indicated are as of December 13, 2000.
(4)   Shares indicated as owned by such entity are owned directly by various private investment accounts, primarily employee benefit plans for which Fidelity Trust Management Trust Company (“FMTC”) serves as trustee or managing agent. FMTC is a wholly-owned subsidiary of FMR and a bank as defined in Section 3(a)(6) of the Securities Exchange Act of 1934, as amended. The holdings indicated are as of December 13, 2000.
(5)   Merrill Lynch, Pierce, Fenner & Smith, Inc. was the Initial Purchaser in a private placement of the LYONs by the Company on November 1, 2000. Merrill Lynch, Pierce, Fenner & Smith, Inc. is not aware of any position, office or directorship relationship with the Company or its affiliates. However, it may or may not have, from time to time, acted in a financial investment advisory capacity to the Company.
(6)   Van Kampen Asset Management, Inc. is the investment advisor to the Van Kampen Harbor Fund and has discretionary authority over its portfolio. Van Kampen Asset Management, Inc. is also the investment advisor to a number of other funds. Those funds hold an aggregate amount of 2,635,165 shares of common stock of the Company.

     The preceding table has been prepared based upon information furnished to us by the Selling Securityholders in the table. From time to time, additional information concerning ownership of the LYONs and common stock may rest with certain Holders thereof not named in the preceding table, with whom we believe we have no affiliation.

     The Selling Securityholders listed in the above table may have sold or transferred, in transactions exempt form the registration requirements of the Securities Act, some or all of their LYONs since the date on which the information is presented in the above table. Information about the Selling Securityholders may change over time. Any changed information will be set forth in prospectus supplements.

     Because the Selling Securityholders may offer all or some of their LYONs or the underlying common stock from time to time, we can not estimate the amount of the LYONs or the underlying common stock that will be held by the Selling Securityholders upon the termination of any particular offering. See “Plan of Distribution.”

The Date of This Prospectus Supplement Is April 24, 2002

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