Multifunctional drugs for endothelial dysfunction in diabetes and glaucoma

IDrugs

Volumn 6, Issue 4, 2003, Pages 360-367

  Wood, Paul L ^a  

^a OxoN Medica Inc   (United States)

Author keywords

Diabetes; Endothelial dysfunction; Endothelin; Glaucoma; Nitric oxide; Superoxide

Indexed keywords

3 HYDROXYMETHYL 2,2,5,5 TETRAMETHYL 1 PYRROLIDINYOXY; 3 NITRATOMETHYLPROXYL; 4 [4 (1,3 BENZODIOXOL 5 YL) 5 (2 PYRIDINYL) 1H IMIDAZOL 2 YL]BENZAMIDE; ANGIOTENSIN RECEPTOR ANTAGONIST; ANTIGLAUCOMA AGENT; ANTIOXIDANT; BOSENTAN; DIPEPTIDYL CARBOXYPEPTIDASE INHIBITOR; ENDOTHELIN; ENDOTHELIN RECEPTOR ANTAGONIST; FREE RADICAL; GLYCERYL TRINITRATE; N TERT BUTYL ALPHA PHENYLNITRONE; NIPRADILOL; NITRIC OXIDE; NITRIC OXIDE DONOR; NITRIC OXIDE SYNTHASE INHIBITOR; NOX 700; ORGANIC NITRATE; OX 020; OX 029; PROBUCOL; PROTEIN KINASE C INHIBITOR; RUBOXISTAURIN; STREPTOZOCIN; SUPEROXIDE; SUPEROXIDE DISMUTASE; SUPEROXIDE DISMUTASE MIMETIC AGENT; TEMPOL; TIMOLOL; UNCLASSIFIED DRUG; UNINDEXED DRUG;

ANTIINFLAMMATORY ACTIVITY; BIOCHEMISTRY; CLINICAL TRIAL; CONJUNCTIVAL HYPEREMIA; DIABETES MELLITUS; DIABETIC NEPHROPATHY; DIABETIC NEUROPATHY; DRUG MECHANISM; DRUG METABOLISM; DRUG STRUCTURE; DRUG TOLERANCE; ENDOTHELIUM CELL; ENDOTHELIUM LESION; GLAUCOMA; HEADACHE; HUMAN; INTRAOCULAR PRESSURE; MIOSIS; NEPHROTOXICITY; NONHUMAN; ORTHOSTATIC HYPOTENSION; OXIDATIVE STRESS; PTOSIS; REVIEW; STREPTOZOCIN DIABETES;

ANTI-INFLAMMATORY AGENTS; DIABETIC ANGIOPATHIES; ENDOTHELINS; ENDOTHELIUM, VASCULAR; ENZYME INHIBITORS; FREE RADICAL SCAVENGERS; GLAUCOMA; NITRIC OXIDE DONORS; NITRIC OXIDE SYNTHASE; NITRIC OXIDE SYNTHASE TYPE III; OCULAR PHYSIOLOGY;

EID: 0037692710     PISSN: 13697056     EISSN: None     Source Type: Journal    
DOI: None     Document Type: Review

References (95)

1. Feng MG, Dukacz SA, Kline RL: Selective effect of Tempol on renal medullary hemodynamics in spontaneously hypertensive rats. Am J Physiol-Regulat Integrat Comparat Physiol (2001) 281:R1420-R1425.
2. Schnackenberg CG, Wilcox CS: Two-week administration of Tempol attenuates both hypertension and renal excretion of 8-iso prostaglandin F2α. Hypertension (1999) 33:424-428.
3. Zamir E, Zhang R, Samuni A, Kogan M, Pe'er J: Nitroxide stable radical suppresses autoimmune uveitis in rats. Free Radic Biol Med (1999) 27:7-15.
4. Wang M, Lam TT, Fu J, Tso MO: Tempol, a superoxide dismutase mimic, ameliorates light-induced retinal degeneration. Res Commun Mol Pathol Pharmacol (1995) 89:291-304.
5. Haj-Yehia A, Nassar T, Lotan C, Münzel T, Benet L, Ångård EE: Development of 3-nitratomethyl-proxyl (NMP): A novel, bifunctional superoxide dismutase-mimic-nitric oxide-donor. Drug Dev Res (2000) 50:528-536.
6. Gallez B, De Meester C, Debuyst R, Dejehet F, Dumont P: Mutagenicity of nitroxyl compounds: Structure-activity relationships. Toxicol Lett (1992) 63:35-45.
7. Samuni A, Mitchell JB, DeGraff W, Krishna CM, Samuni U, Russo A: Nitroxide SOD-mimics: Modes of action. Free Radic Res Commun (1991) 12:187-194.
8. Wink DA, Mitchell JB: Chemical biology of nitric oxide: Insights into regulatory, cytotoxic, and cytoprotective mechanisms of nitric oxide. Free Radic Biol Med (1998) 25: 434-456.
9. Ruef J, Moser M, Kubler W, Bode C: Induction of endothelin-1 expression by oxidative stress in vascular smooth muscle cells. Cardiovasc Pathol (2001) 10:311-315.
10. Christman JW, Blackwell TS, Juurlink BH: Redox regulation of nuclear factor κB: Therapeutic potential for attenuating inflammatory responses. Brain Pathol (2000) 10:153-162.
11. Thatcher GRJ, Weldon H: NO problem for nitroglycerin: Organic nitrate chemistry and therapy. Chem Soc Rev (1998) 27:331-337.
12. Ignarro LJ, Napoli C, Loscalzo J: Nitric oxide donors and cardiovascular agents modulating the bioactivity of nitric oxide: An overview. Circ Res (2002) 90:21-28. An overview of agents that affect NO, and their mechanisms of action.
13. Schwemmer M, Fink B, Kockerbauer R, Bassenge E: How urine analysis reflects oxidative stress - Nitrotyrosine as a potential marker. Clin Chim Acta (2000) 297:207-216.
14. BioPartnering - Medinox Inc. Eighth Annual Biopartnering Europe Meeting, London, UK (2000) October 16-17.
15. Gorogawa S, Kajimoto Y, Umayahara Y, Kaneto H, Watada H, Kuroda A, Kawamori D, Yasuda T, Matsuhisa M, Yamasaki Y, Hori M: Probucol preserves pancreatic β-cell function through reduction of oxidative stress in type 2 diabetes. Diabetes Res Clin Pract (2002) 57:1-10.
16. Ho E, Chen G, Bray TM: α-Phenyl-tert-butylnitrone (PBN) inhibits NFκB activation offering protection against chemically induced diabetes. Free Radic Biol Med (2000) 28:604-614.
17. Lehrman S, Romano P, Frishman W, Rashid A, Dobkin J, Reichel J: Primary pulmonary hypertension and cor pulmonale. Cardiol Rev (2002) 10:265-278.
18. Laping NJ, Grygielko E, Mathur A, Butter S, Bomberger J, Tweed C, Martin W, Fornwald J, Lehr R, Harling J, Gaster L: Inhibition of transforming growth factor (TGF)-β I-induced extracellular matrix with a novel inhibitor of the TGF-β type I receptor kinase activity: SB-431542. Mol Pharmacol (2002) 62:58-64.
19. Frank RN: Potential new medical therapies for diabetic retinopathy: Protein kinase C inhibitors. Am J Opthalmol (2002) 133:693-698.
20. Beckman JA, Goldfine AB, Gordon MB, Garrett LA, Creager MA: Inhibition of protein kinase C β prevents impaired endothelium-dependent vasodilation caused by hyperglycemia in humans. Circ Res (2002) 90:107-111.
21. Gopaul NK, Manraj MD, Hébé A, Lee Kwai Yan S, Johnston A, Carrier MJ, Änggård EE: Oxidative stress could precede endothelial dysfunction and insulin resistance in Indian Mauritians with impaired glucose metabolism. Diabetologia (2001) 44:706-712.
22. Evans JL, Goldfine ID, Maddux BA, Grodsky GM: Oxidative stress and stress-activated signaling pathways: A unifying hypothesis of type 2 diabetes. Endocr Rev (2002) 23:599-622.
23. Annuk M, Felström B, Akerblom O, Zilmer K, Vihalemm T, Zilmer M: Oxidative stress markers in pre-uremic patients. Clin Nephrol (2001) 56:308-314.
24. Annuk M, Zilmer M, Lind L, Linde T, Fellstrom B: Oxidative stress and endothelial function in chronic renal failure. J Am Soc Nephrol (2001) 12:2747-2752.
25. Ha H, Kim KH: Role of oxidative stress in the development of diabetic nephropathy. Kidney Int (1995) 48(Suppl 51):S18-S21.
26. Ishii N, Patel KP, Lane PH, Taylor T, Bian K, Murad F, Pollock JS, Carmines PK: Nitric oxide synthesis and oxidative stress in the renal cortex of rats with diabetes mellitus. J Am Soc Nephrol (2001) 12:1630-1639.
27. Ceriello A, Mercuri F, Quagliaro L, Assaloni R, Motz E, Tonutti L, Taboga C: Detection of nitrotyrosine in the diabetic plasma: Evidence of oxidative stress. Diabetologia (2001) 44:838-838.
28. Thuraisingham RC, Nott CA, Dodd SM, Yaqoob MM: Increased nitrotyrosine staining in kidneys from patients with diabetic nephropathy. Kidney Int (2000) 57:1968-1972.
29. Nishida T, Nakagawa S, Manabe R: Superoxide dismutase activity in diabetic rat retina. Jpn J Ophthalmol (1984) 28:377-382.
30. Bustamante J, Lodge JK, Marcocci L, Tritschler HJ, Packer L, Rihn BH: α-Lipoic acid in liver metabolism and disease. Free Radic Biol Med (1998) 24:1023-1039. A review on α-lipoic acid, with human data suggesting the effects of the metabolism modular.
31. Earle KA, Mehrotra S, Dalton RN, Denver E, Swaminathan R: Defective nitric oxide production and functional renal reserve in patients with type 2 diabetes who have microalbuminuria of African and Asian compared with white origin. J Am Soc Nephrol (2001) 12:2125-2130.
32. Raj DS, Vincent B, Simpson K, Sato E, Tones KL, Welbourne TC, Levi M, Shah V, Blandon P, Zager P, Robbins RA: Hemodynamic changes during hemodialysis: Role of nitric oxide and endothelin. Kidney Int (2002) 61:697-704.
33. Onozato ML, Tojo A, Goto A, Fujita T, Wilcox CS: Oxidative stress and nitric oxide synthase in rat diabetic nephropathy: Effects of ACEI and ARB. Kidney Int (2002) 61:186-194.
34. Asakimori Y, Yorioka N, Yamamoto I, Okumoto S, Doi S, Hirai T, Taniguchi Y: Endothelial nitric oxide synthase intron 4 polymorphism influences the progression of renal disease. Nephron (2001) 89:219-223.
35. Zoccali C, Bode-Boger S, Mallamaci F, Benedetto F, Tripepi G, Malatino L, Cataliotti A, Bellanuova I, Fermo I, Frolich JC, Boger A: Plasma concentration of assymetrical dimethylarginine and mortality in patients with end-stage renal disease: A prospective study. Lancet (2001) 358:2113-2117.
36. Wessels J, Peake P, Pussell BA, Macdonald GJ: Nitric oxide synthase inhibition in a spontaneously hypertensive rat model of diabetic nephropathy. Clin Exp Pharmacol Physiol (1997) 24:451-453.
37. Jover B, Mimran A: Nitric oxide inhibition and renal alterations. J Cardiovasc Pharmacol (2001) 38(Suppl 2):S65-S70.
38. Chen HC, Guh JY, Shin SJ, Tsai JH, Lai YH: Reactive oxygen species enhances endothelin-1 production of diabetic rat glomeruli in vitro and in vivo. J Lab Clin Med (2000) 135:309-315.
39. Ito Y, Imamura S, Yamamoto K, Ono Y, Nagata M, Kobayashi T, Kato T, Tomita M, Naka A, Itoh M, Nagasaka A: Changes of endothelin in streptozotocin-induced diabetic rats: Effects of an angiotensin converting enzyme inhibitor, enalapril maleate. J Endocrinol (2002) 175:233-239.
40. Hargrove GM, Dufresne J, Whiteside C, Muruve DA, Wong NC: Diabetes mellitus increases endothelin-1 gene transcription in rat kidney. Kidney Int (2000) 58:1534-1545.
41. Khan MA, Dashwood MR, Mumtaz FH, Thompson CS, Mikhailidis DP, Morgan RJ: Upregulation of endothelin A receptor sites in the rabbit diabetic kidney: Potential relevance to the early pathogenesis of diabetic nephropathy. Nephron (1999) 83:261-267.
42. Hocher B, Schwarz A, Reinbacher D, Jacobi J, Lun A, Priem F, Bauer C, Neumayer HH, Raschack M: Effects of endothelin receptor antagonists on the progression of diabetic nephropathy. Nephron (2001) 87:161-169.
43. Ivic MA, Stefanovic V: Endothelins in hypertension and kidney diseases. Pathol Biol (1998) 46:723-730.
44. Hong CY, Chia KS: Markers of diabetic nephropathy. J Diabetes Complications (1998) 12:43-60.
45. Fagerudd JA, Groop PH, Honkanen E, Teppo AM, Gronhagen-Riska C: Urinary excretion of TGF-β 1, PDGF-BB and fibronectin in insulin-dependent diabetes mellitus patients. Kidney Int Suppl (1997) 63:S195-S197.
46. Kanters SD, Banga JD, Algra A, Frijns RC, Beutler JJ, Fijnheer R: Plasma levels of cellular fibronectin in diabetes. Diabetes Care (2001) 24:323-327.
47. Nishimura M, Sasaki T, Ohishi A, Oishi M, Kono S, Totani Y, Kato Y, Noto Y, Misaki S, Higashi K, Shimada F: Angiotensin-converting enzyme inhibitors and probucol suppress the time-dependent increase in urinary type IV collagen excretion of type II diabetes mellitus patients with early diabetic nephropathy. Clin Nephrol (2001) 56:96-103.
48. Dogra G, Rich L, Stanton K, Watts GF: Endothelium-dependent and independent vasodilation studies at normoglycaemia in type I diabetes mellitus with and without microalbuminuria. Diabetologia (2001) 44:593-601.
49. Mulle MJ, Clarkson P, Donald AE, Thomson H, Thorne SA, Powe AJ, Furuno T, Bull T, Deanfield JE: Effect of enalapril on endothelial function in young insulin dependent diabetic patients: A randomized, double-blind study. J Am Coll Cardiol (1998) 31:1330-1335.
50. Schalkwijk CG, Smulders RA, Lambert J, Donker AJ, Stehouwer CD: ACE-inhibition modulates some endothelial functions in healthy subjects and in normotensive type 1 diabetic patients. Eur J Clin Invest (2000) 30:853-860.
51. Tan KC, Chow WS, Ai VH, Lam KS: Effects of angiotensin II receptor antagonist on endothelial vasomotor function and urinary albumin excretion in type 2 diabetic patients with microalbuminuria. Diabetes Metab Res Rev (2002) 18:71-76.
52. Van De Ree MA, Huisman MV, De Man FH, Van Der Vijver JC, Meinders AE, Blauw GJ: Impaired endothelium-dependent vasodilation in type 2 diabetes mellitus and the lack of effect of simvastatin. Cardiovasc Res (2001) 52:299-305.
53. Van Etten RW, De Koning EJ, Honing ML, Stroes ES, Gaillard CA, Rabelink TJ: Intensive lipid lowering by statin therapy does not improve vasoreactivity in patients with type 2 diabetes. Arterioscler Thromb Vasc Biol (2002) 22:799-804.
54. Van Venrooij FV, Van De Ree MA, Bots ML, Stolk RP, Huisman MV, Banga JD: Aggressive lipid lowering does not improve endothelial function in type 2 diabetes: The Diabetes Atorvastatin Lipid Intervention (DALI) Study: A randomized, double-blind, placebo-controlled trial. Diabetes Care (2002) 25: 1211-1216.
55. Bilsborough W, O'Driscoll G, Stanton K, Weerasooriya R, Dembo L, Taylor R, Green D: Effect of lowering tumour necrosis factor-α on vascular endothelial function in type II diabetes. Clin Sci (2002) 103:163-169.
56. Parving HH, Hovind P, Rossing K, Andersen S: Evolving strategies for renoprotection: Diabetic nephropathy. Curr Opin Nephrol Hypertens (2001) 10:515-522.
57. Acbay O: Effects of low-dose losartan treatment on persistent microalbuminuria in normotensive type 1 diabetic subjects. J Endocrinol Invest (2001) 24:608-611.
58. Fernandez R, Puig JG, Rodriguez-Perez JC, Garrido J, Redon J: Effect of two antihypertensive combinations on metabolic control in type-2 diabetic hypertensive patients with albuminuria: A randomized, double-blind study. J Hum Hypertens (2001) 15:849-856.
59. Mayer G: Results from the TIP (Tritace in Proteinuria) intensified monitoring project. Kidney Blood Press Res (2002) 25:80-86.
60. Klahr S, Morrissey JJ: Comparative study of ACE inhibitors and angiotensin II receptor antagonists in interstitial scarring. Kidney Int (1997) 52(Suppl 63):S111-S114.
61. Tütüncü NB, Gürlek A, Gedik O: Efficacy of ACE inhibitors and ATII receptor blockers in patients with microalbuminuria: A prospective study. Acta Diabetol (2001) 38:157-161.
62. Katayama S, Kikkawa R, Isogai S, Sasaki N, Matsuura N, Tajima N, Urakami T, Uchigata Y, Ohashi Y: Effect of captopril or imidapril on the progression of diabetic nephropathy in Japanese with type 1 diabetes mellitus: A randomized controlled study (JAPAN-IDDM). Diabetes Res Clin Pract (2002) 55:113-121.
63. Brenner BM, Cooper ME, De Zeeuw D, Keane WF, Mitch WE, Parving HH, Remuzzi G, Snapinn SM, Zhang Z, Shahinfar S: Effects of losartan on renal and cardiovascular outcomes in patients with type 2 diabetes and nephropathy. N Engl J Med (2001) 345:861-869.
64. Lewis EJ, Hunsicker LG, Clarke WR, Berl T, Pohl MA, Lewis JB, Ritz E, Atkins RC, Rohde R, Raz I: Renoprotective effect of the angiotensin-receptor antagonist irbesartan in patients with nephropathy due to type 2 diabetes. N Engl J Med (2001) 345:851-860.
65. Nassar T, Kadery B, Lotan C, Da'as N, Kleinman Y, Haj-Yehia A: Effects of the superoxide dismutase-mimetic compound Tempol on endothelial dysfunction in stretozotocin-induced diabetic rats. Eur J Pharmacol (2002) 436:111-118.
66. Haj-Yehia A, Nassar T, Lotan C, Munzel T, Anggard EA, Benet LZ: Beneficial effects of tempol nitrate, a bifunctional SOD mimetic-NO donor on diabetes-induced endothelial dysfunction in rats. (2003): manuscript in preparation.
67. Tal M: A novel antioxidant alleviates heat hyperalgesia in rats with an experimental painful peripheral neuropathy. Neuroreport (1996) 7:1382-1384.
68. Alward WL: Medical management of glaucoma. N Eng J Med (1998) 339:1298-1307.
69. Yorio T, Krishnamoorthy R, Prasanna G: Endothelin: Is it a contributor to glaucoma pathophysiology? J Glaucoma (2002) 11:259-270. A review on endothelin receptors in the eye and the ocular actions off endothelins.
70. Lütjen-Drecoll E: Functional morphology of the trabecular meshwork in primate eyes. Prog Retinal Eye Res (1998) 18:91-119.
71. Li Y, Yi YZ: Histochemical and electron microscopic studies of the trabecular meshwork in primary open-angle glaucoma. Eye Sci (1985) 1:17-28.
72. Neufeld AH: Nitric oxide: A potential mediator of retinal ganglion cell damage in glaucoma. Surv Ophthalmol (1999) 43:S129-S135.
73. Zhou L, Li Y, Yue BY: Oxidative stress affects cytoskeletal structure and cell-matrix interactions in cells from an ocular tissue: The trabecular meshwork. J Cell Physiol (1999) 180:182-189.
74. De La Paz MA, Epstein DL: Effect of age on superoxide dismutase activity of human trabecular meshwork. Invest Ophthalmol Vis Sci (1996) 37:1849-1853.
75. Nishida T, Nakagawa S, Manabe R: Superoxide dismutase activity in diabetic rat retina. Jpn J Ophthalmol (1984) 28:377-382.
76. Gonzalez P, Epstein DL, Borras T: Genes upregulated in the human trabecular meshwork in response to elevated intraocular pressure. Invest Ophthalmol Vis Sci (2000) 41:352-361.
77. Doganay S, Evereklioglu C, Turkoz Y, Er H: Decreased nitric oxide production in primary open-angle glaucoma. Eur J Ophthalmol (2002) 12:44-48.
78. Nathanson JA, McKee M: Alterations of ocular nitric oxide synthase in human glaucoma. Invest Ophthalmol Vis Sci (1995) 36:1774-1784.
79. Noske W, Hensen J, Wiederholt M: Endothelin-like immunoreactivity in aqueous humor of patients with primary open-angle glaucoma and cataract. Graefe's Arch Clin Exp Ophthalmol (1997) 235:551-552.
80. Kallberg ME, Brooks DE, Garcia-Sanchez GA, Komaromy AM, Szabo NJ, Tian L: Endothelin 1 levels in the aqueous humor of dogs with glaucoma. J Glaucoma (2002) 11:105-109.
81. Polska E, Doelemeyer A, Luksch A, Ehrlich P, Kaehler N, Percicot CL, Lambrou GN, Schmetterer L: Partial antagonism of endothelin 1-induced vasoconstriction in the human choroids by topical unoprostone isopropyl. Arch Ophthalmol (2002) 120:348-352.
82. Sugiyama T, Moriya S, Oku H, Azuma I: Association of endothelin-1 with normal tension glaucoma: Clinical and fundamental studies. Surv Ophthalmol (1995) 39(Suppl 1):S49-S56.
83. Wang N, Chintala SK, Fini ME, Schuman JS: Activation of a tissue-specific stress response in the aqueous outflow pathway of the eye defines the glaucoma disease phenotype. Nat Med (2001) 7:304-309.
84. Yuan L, Neufeld AH: Activated microglia in the human glaucomatous optic nerve head. J Neurosci Res (2001) 64:523-532.
85. Inatani M, Tanihara H, Katsuta H, Honjo M, Kido N, Honda Y: Transforming growth factor-β 2 levels in aqueous humor of glaucomatous eyes. Graefe's Arch Clin Exp Ophthalmol (2001) 239:109-113.
86. Ochiai Y, Ochiai H: Higher concentration of transforming growth factor-β in aqueous humor of glaucomatous eyes and diabetic eyes. Jpn J Ophthalmol (2002) 46:249-253.
87. Cao Y, Wei H, Zhang Y, Da B, Lu Y: Effect of transforming growth factor-β(2) on extracellular matrix synthesis in bovine trabecular meshwork cells. Chung Hua Yen Ko Tsa Chih (2002) 38:429-432.
88. Kotikoski H, Alajuuma P, Moilanen E, Salmenpera P, Oksala O, Laippala P, Vapaatalo H: Comparison of nitric oxide donors in lowering intraocular pressure in rabbits: Role of cyclic GMP. J Ocul Pharmacol Ther (2002) 18:11-23.
89. Kanno M, Araie M, Tomita K, Sawanobori K: Effects of topical nipradilol, a β-blocking agent with α-blocking and nitroglycerin-like activities, on aqueous humor dynamics and fundus circulation. Invest Ophthalmol Vis Sci (1998) 39:736-743.
90. Kanno M, Araie M, Koibuchi H, Masuda K: Effects of topical nipradilol, a β blocking agent with α blocking agent and nitroglycerin-like activities, on intraocular pressure and aqueous dynamics in humans. Br J Ophthalmol (2000) 84:293-299.
91. Wizemann A, Wizemann V: The use of organic nitrates to lower intraocular pressure in outpatient and surgical treatment. Klin Monatsbl Augenheilkd (1980) 177:292-295.
92. Ranchon I, Chen S, Alvarez K, Anderson RE: Systemic administration of phenyl-N-tert-butylnitrone protects the retina from light damage. Invest Ophthalmol Vis Sci (2001) 42:1375-1379.
93. Mizuno K, Koide T, Yoshimura M, Araie M: Neuroprotective effect and intraocular penetration of nipradilol, a β-blocker with nitric oxide donative action. Invest Ophthalmol Vis Sci (2001) 42:688-694.
94. Tomita H, Nakazawa T, Sugano E, Abe T, Tamai M: Nipradilol inhibits apoptosis by preventing the activation of caspase-3 via S-nitrosylation and the cGMP-dependent pathway. Eur J Pharmacol (2002) 452:263-268.
95. Shaya FT, Mullins CD, Wong W, Cho J: Discontinuation rates of topical glaucoma medications in a managed care population. Am J Manag Care (2002) 8:S271-S277.