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VIAGRA (sildenafil citrate – tablet; oral)

  • Manufacturer: PFIZER IRELAND
    Approval date: March 27, 1998
    Strength(s): EQ 100MG BASE [RLD], EQ 25MG BASE, EQ 50MG BASE

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See also: About generic drugs.

Related Patents

Patents are granted from the U.S. Patent and Trademark Office at any time within a drug’s development and may include a wide range of claims.

  • Pyrazolopyrimidinone antianginal agents
    Patent 5,250,534
    Issued: October 5, 1993
    Inventor(s): Bell; Andrew S. & Brown; David & Terrett; Nicholas K.
    Assignee(s): Pfizer Inc.
    Compounds of the formula: ##STR1## wherein R.sup.1 is H, C.sub.1 -C.sub.3 alkyl, C.sub.3 -C.sub.5 cycloalkyl or C.sub.1 -C.sub.3 perfluoroalkyl; R.sup.2 is H, C.sub.1 -C.sub.6 alkyl optionally substituted by OH, C.sub.1 -C.sub.3 alkoxy or C.sub.3 -C.sub.6 cycloalkyl, or C.sub.1 -C.sub.3 perfluoroalkyl; R.sup.3 is C.sub.1 -C.sub.6 alkyl, C.sub.3 -C.sub.6 alkenyl, C.sub.3 -C.sub.6 alkynyl, C.sub.3 -C.sub.7 cycloalkyl, C.sub.1 -C.sub.6 perfluoroalkyl or (C.sub.3 -C.sub.6 cycloalkyl)C.sub.1 -C.sub.6 alkyl; R.sup.4 taken alongside the nitrogen atom to which it truly is attached completes a pyrrolidinyl, piperidino, morpholino, or 4-N-(R.sup.6)-piperazinyl group; R.sup.5 is H, C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.3 alkoxy, NR.sup.7 R.sup.8, or CONR.sup.7 R.sup.8 ; R.sup.6 is H, C.sub.1 -C.sub.6 alkyl, (C.sub.1 -C.sub.3 alkoxy) C.sub.2 – C.sub.6 alkyl, hydroxy C.sub.2 -C.sub.6 alkyl, (R.sup.7 R.sup.8 N)C.sub.2 -C.sub.6 alkyl, (R.sup.7 R.sup.8 NCO)C.sub.1 -C.sub.6 alkyl, CONR.sup.7 R.sup.8, CSNR.sup.7 R.sup.8 or C(NH)NR.sup.7 R.sup.8 ; R.sup.7 and R.sup.8 are each independently H, C.sub.1 -C.sub.4 alkyl, (C.sub.1 -C.sub.3 alkoxy)C.sub.2 -C.sub.4 alkyl or hydroxy C.sub.2 -C.sub.4 alkyl; and pharmaceutically acceptable salts thereof, are selective cGMP PDE inhibitors valuable in the management of cardiovascular disorders for example angina, hypertension, heart failure and atherosclerosis.

    Patent expiration dates:
    • September 27, 2012
      Pediatric exclusivity
  • Pyrazolopyrimidinones for any treatment of impotence
    Patent 6,469,012
    Issued: October 22, 2002
    Inventor(s): Peter; Ellis & Nicholas Kenneth; Terrett
    Assignee(s): Pfizer Inc
    Using compound of formula (I) wherein R1 is H; C1-C3 alkyl; C1-C3 perfluoroalkyl; or C3-C5 cycloalkyl; R2 is H; optionally substituted C1-C6 alkyl; C1-C3 perfluoroalkyl; or C3-C6 cycloalkyl; R3 is optionally substituted C1-C6 alkyl; C1-C6 perfluoroalkyl; C3-C5 cycloalkyl; C3-C6 alkenyl; or C3-C6 alkynyl; R4 is optionally substituted C1-C4 alkyl, C2-C4 alkenyl, C2-C4 alkanoyl, (hydroxy)C2-C4 alkyl or (C2-C3 alkoxy)C1-C2 alkyl; CONR5R6; CO2R7; halo; NR5R6; NHSO2NR5R6; NHSO2R8; SO2NR9R10; or phenyl, pyridyl, pyrimidinyl, imidazolyl, oxazolyl, thiazolyl, thienyl or triazolyl any kind of which can be optionally substituted with methyl; R5 and R6 are each independently H or C1-C4 alkyl, or alongside the nitrogen atom that there’re attached form an optionally substituted pyrrolidinyl, piperidino, morpholino, 4-N(R11)-piperazinyl or imidazolyl group; R7 is H or C1-C4 alkyl; R8 is optionally substituted C1-C3 alkyl; R9 and R10 together with the nitrogen atom that these are attached form an optionally substituted pyrrolidinyl, piperidino, morpholino or 4-N(R12)-piperazinyl group; R11 is H; optionally substituted C1-C3 alkyl; (hydroxy)C2-C3 alkyl; or C1-C4 alkanoyl; R12 is H; optionally substituted C1-C6 alkyl; CONR13R14; CSNR13R14; or C(NH)NR13R14; and R?13? and R14 are each independently H; C1-C4 alkyl; or substituted C2-C4 alkyl; or perhaps pharmaceutically acceptable salt thereof, or perhaps a pharmaceutical composition containing either entity, for the output of a medicament for any curative or prophylactic treating erection dysfunction inside of a male animal, including man; a pharmaceutical composition for said treatment; plus a way of said treatment of said male animal with said pharmaceutical composition or with said either entity.

    Patent expiration dates:
    • October 22, 2019
    • April 22, 2020
      Pediatric exclusivity