Timolol Explained

Watchedfields:changed
Verifiedrevid:457286138
Width:200
Tradename:Betimol, Blocadren, Istalol, Timoptic, others
Drugs.Com:Maleate
eent
Dailymedid:Timolol
Pregnancy Au:C
Routes Of Administration:By mouth, topical (eye drop)
Class:Beta blocker
Atc Prefix:C07
Atc Suffix:AA06
Atc Supplemental:
Combination:
Legal Ca:Rx-only
Legal Ca Comment:[1]
Legal Uk:POM
Legal Us:Rx-only
Bioavailability:60%
Metabolism:Liver (80%, mainly CYP2D6[2])
Onset:15–30 min
Elimination Half-Life:2.5–5 hours
Duration Of Action:24 hours
Excretion:Kidney
Index2 Label:as salt
Cas Number:26839-75-8
Pubchem:33624
Iuphar Ligand:565
Drugbank:DB00373
Chemspiderid:31013
Unii:5JKY92S7BR
Kegg:D08600
Kegg2:D00603
Chebi:9599
Chembl:499
Iupac Name:(S)-1-(tert-Butylamino)-3-[(4-morpholin-4-yl-1,2,5-thiadiazol-3-yl)oxy]propan-2-ol
C:13
H:24
N:4
O:3
S:1
Smiles:CC(C)(C)NCC(O)COc1nsnc1N1CCOCC1
Stdinchi:1S/C13H24N4O3S/c1-13(2,3)14-8-10(18)9-20-12-11(15-21-16-12)17-4-6-19-7-5-17/h10,14,18H,4-9H2,1-3H3/t10-/m0/s1
Stdinchikey:BLJRIMJGRPQVNF-JTQLQIEISA-N

Timolol is a beta blocker medication used either by mouth or as eye drops. As eye drops it is used to treat increased pressure inside the eye such as in ocular hypertension and glaucoma. By mouth it is used for high blood pressure, chest pain due to insufficient blood flow to the heart, to prevent further complications after a heart attack, and to prevent migraines.[3]

Common side effects with the drops is irritation of the eye. Common side effects by mouth include tiredness, slow heart beat, itchiness, and shortness of breath.[3] Other side effects include masking the symptoms of low blood sugar in those with diabetes. Use is not recommended in those with asthma, uncompensated heart failure, or COPD. It is unclear if use during pregnancy is safe for the fetus.[4] Timolol is a non-selective beta blocker.

Timolol was patented in 1968, and came into medical use in 1978.[5] It is on the World Health Organization's List of Essential Medicines.[6] Timolol is available as a generic medication.[7] [8] In 2021, it was the 163rd most commonly prescribed medication in the United States, with more than 3million prescriptions.[9] [10]

Medical uses

By mouth

In its by mouth or oral form, it is used:

The combination of timolol and the alpha-1 blocker prazosin has sedative effects.[12]

Eye drops

In its eye drop form it is used to treat open-angle and, occasionally, secondary glaucoma.[13] The mechanism of action of timolol is probably the reduction of the formation of aqueous humor in the ciliary body in the eye. It was the first beta blocker approved for topical use in treatment of glaucoma in the United States (1978).[14] When used by itself, it depresses intraocular pressure (IOP) 18–34% below baseline within first few treatments. However, there are short-term escape and long-term drift effects in some people. That is, tolerance develops. It may reduce the extent of the daytime IOP curve up to 50%. The IOP is higher during sleep. Efficacy of timolol in lowering IOP during the sleep period may be limited.[15] [16] [17] It is a 5–10× more potent beta blocker than propranolol. Timolol is light-sensitive; it is usually preserved with 0.01% benzalkonium chloride (BAC), but also comes BAC-free. It can also be used in combination with pilocarpine, carbonic anhydrase inhibitors[18] or prostaglandin analogs.[19]

A Cochrane review compared the effect of timolol versus brimonidine in slowing the progression of open angle glaucoma in adults but found insufficient evidence to come to conclusions.[20]

On the skin

In its gel form it is used on the skin to treat infantile hemangiomas.[21]

Contraindications

The medication should not be taken by individuals with:[22]

Side effects

The most serious possible side effects include cardiac arrhythmias and severe bronchospasms. Timolol can also lead to fainting, congestive heart failure, depression, confusion, worsening of Raynaud's syndrome and impotence.

Side effects when given in the eye include: burning sensation, eye redness, superficial punctate keratopathy, corneal numbness.[24]

Formulations

It is available in tablet and liquid formulations.

For ophthalmic use, timolol is also available combined:

Brand names

Timolol is marketed under many trade names worldwide.[25] Timolol eye drops are marketed under the brand name Istalol among others.[26] [27]

External links

Notes and References

  1. Web site: Product monograph brand safety updates . Health Canada . February 2024 . 24 March 2024.
  2. Volotinen M, Turpeinen M, Tolonen A, Uusitalo J, Mäenpää J, Pelkonen O . Timolol metabolism in human liver microsomes is mediated principally by CYP2D6 . Drug Metabolism and Disposition . 35 . 7 . 1135–1141 . July 2007 . 17431033 . 10.1124/dmd.106.012906 . 794764 .
  3. Web site: Timolol Maleate. The American Society of Health-System Pharmacists. 8 December 2016. live. https://web.archive.org/web/20161228200029/https://www.drugs.com/monograph/timolol-maleate.html. 28 December 2016.
  4. Web site: Timolol ophthalmic Use During Pregnancy . The American Society of Health-System Pharmacists. 28 December 2016. live. https://web.archive.org/web/20161228200050/https://www.drugs.com/pregnancy/timolol-ophthalmic.html. 28 December 2016.
  5. Book: Fischer J, Ganellin CR . Analogue-based Drug Discovery . 2006 . John Wiley & Sons . 9783527607495 . 460 . live . https://web.archive.org/web/20161228195510/https://books.google.ca/books?id=FjKfqkaKkAAC&pg=PA460 . 28 December 2016 .
  6. Book: ((World Health Organization)) . World Health Organization model list of essential medicines: 21st list 2019 . 2019 . 10665/325771 . World Health Organization . World Health Organization . Geneva . WHO/MVP/EMP/IAU/2019.06. License: CC BY-NC-SA 3.0 IGO . free .
  7. Web site: Timolol eent . The American Society of Health-System Pharmacists . 8 December 2016 . live. https://web.archive.org/web/20161228195957/https://www.drugs.com/monograph/timolol-eent.html . 28 December 2016 .
  8. Web site: Competitive Generic Therapy Approvals . U.S. Food and Drug Administration (FDA) . 29 June 2023 . 29 June 2023 . 29 June 2023 . https://web.archive.org/web/20230629233651/https://www.fda.gov/drugs/generic-drugs/competitive-generic-therapy-approvals . live .
  9. Web site: The Top 300 of 2021 . ClinCalc . 14 January 2024 . 15 January 2024 . https://web.archive.org/web/20240115223848/https://clincalc.com/DrugStats/Top300Drugs.aspx . live .
  10. Web site: Timolol - Drug Usage Statistics . ClinCalc . 14 January 2024.
  11. Book: Marcus DA, Bain PA . Effective Migraine Treatment in Pregnant and Lactating Women: A Practical Guide . 14 November 2010 . 27 February 2009 . シュプリンガー・ジャパン株式会社 . 978-1-60327-438-8 . 141– . live . https://web.archive.org/web/20171105201118/https://books.google.com/books?id=Z5YWpjj89NEC&pg=PA141 . 5 November 2017 .
  12. Atkin T, Comai S, Gobbi G. Gabriella Gobbi . Drugs for Insomnia beyond Benzodiazepines: Pharmacology, Clinical Applications, and Discovery . Pharmacol Rev . 70 . 2 . 197–245 . April 2018 . 29487083 . 10.1124/pr.117.014381 . 3578916 . free .
  13. Web site: Timolol Ophthalmic . MedlinePlus . 15 April 2017 . 31 December 2019.
  14. Sambhara D, Aref AA . Glaucoma management: relative value and place in therapy of available drug treatments . Therapeutic Advances in Chronic Disease . 5 . 1 . 30–43 . January 2014 . 24381726 . 3871276 . 10.1177/2040622313511286 .
  15. Liu JH, Kripke DF, Weinreb RN . Comparison of the nighttime effects of once-daily timolol and latanoprost on intraocular pressure . American Journal of Ophthalmology . 138 . 3 . 389–95 . September 2004 . 15364220 . 10.1016/j.ajo.2004.04.022 .
  16. Liu JH, Medeiros FA, Slight JR, Weinreb RN . Comparing diurnal and nocturnal effects of brinzolamide and timolol on intraocular pressure in patients receiving latanoprost monotherapy . Ophthalmology . 116 . 3 . 449–54 . March 2009 . 19157559 . 10.1016/j.ophtha.2008.09.054 .
  17. Liu JH, Slight JR, Vittitow JL, Scassellati Sforzolini B, Weinreb RN . Efficacy of Latanoprostene Bunod 0.024% Compared With Timolol 0.5% in Lowering Intraocular Pressure Over 24 Hours . American Journal of Ophthalmology . 169 . 249–257 . September 2016 . 27457257 . 10.1016/j.ajo.2016.04.019 . free .
  18. Strohmaier K, Snyder E, Adamsons I . A multicenter study comparing dorzolamide and pilocarpine as adjunctive therapy to timolol: patient preference and impact on daily life . Journal of the American Optometric Association . 69 . 7 . 441–51 . July 1998 . 9697378 .
  19. Web site: Ganfort 0.3 mg/ml + 5 mg/ml eye drops, solution - Summary of Product Characteristics (SmPC) . (emc) . 20 February 2020 . 1 March 2020.
  20. Sena DF, Lindsley K . Neuroprotection for treatment of glaucoma in adults . The Cochrane Database of Systematic Reviews . 1 . 1 . CD006539 . January 2017 . 28122126 . 5370094 . 10.1002/14651858.CD006539.pub4 .
  21. Novoa M, Baselga E, Beltran S, Giraldo L, Shahbaz A, Pardo-Hernandez H, Arevalo-Rodriguez I . Interventions for infantile haemangiomas of the skin . The Cochrane Database of Systematic Reviews . 2018 . CD006545 . April 2018 . 4 . 29667726 . 6513200 . 10.1002/14651858.CD006545.pub3 .
  22. Web site: Timolol Maleate tablet . DailyMed . 17 August 2006 . 1 December 2019.
  23. Web site: Package leaflet: Information for the user Timolol. hpra.ie.
  24. Web site: Betimol- timolol solution . DailyMed . 18 March 2010 . 1 December 2019.
  25. Web site: Timolol. Drugs.com. 28 December 2016. live. https://web.archive.org/web/20160307081135/http://www.drugs.com/international/timolol.html. 7 March 2016.
  26. Web site: Generic Istalol Availability . . 20 June 2019.
  27. Web site: Istalol . . 1 August 2018 . 19 July 2019.

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