Timolol

Last updated

Timolol
Timolol structure.svg
Timolol ball-and-stick.png
Clinical data
Trade names Blocadren, Timoptic, others [1]
AHFS/Drugs.com Maleate Monograph
eent Monograph
MedlinePlus a684029
License data
Pregnancy
category
  • AU:C
Routes of
administration 		By mouth, topical (eye drop)
Drug class Beta blocker
ATC code
Legal status
Legal status
Pharmacokinetic data
Bioavailability 60%
Metabolism Liver (80%, mainly CYP2D6 [3] )
Onset of action 15–30 min [4]
Elimination half-life 2.5–5 hours
Duration of action 24 hours [4]
Excretion Kidney
Identifiers
  • (S)-1-(tert-Butylamino)-3-[(4-morpholin-4-yl-1,2,5-thiadiazol-3-yl)oxy]propan-2-ol
CAS Number
PubChem CID
IUPHAR/BPS
DrugBank
ChemSpider
UNII
KEGG
ChEBI
ChEMBL
CompTox Dashboard (EPA)
ECHA InfoCard 100.043.651 OOjs UI icon edit-ltr-progressive.svg
Chemical and physical data
Formula C13H24N4O3S
Molar mass 316.42 g·mol−1
3D model (JSmol)
  • CC(C)(C)NCC(O)COc1nsnc1N1CCOCC1
  • InChI=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 Yes check.svgY
  • Key:BLJRIMJGRPQVNF-JTQLQIEISA-N Yes check.svgY
   (verify)

Timolol is a beta blocker medication used either by mouth or as eye drops. [4] [5] As eye drops it is used to treat increased pressure inside the eye such as in ocular hypertension and glaucoma. [4] 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. [5]

Contents

Common side effects with the drops is irritation of the eye. [4] Common side effects by mouth include tiredness, slow heart beat, itchiness, and shortness of breath. [5] Other side effects include masking the symptoms of low blood sugar in those with diabetes. [4] Use is not recommended in those with asthma, uncompensated heart failure, or chronic obstructive pulmonary disease (COPD). [4] It is unclear if use during pregnancy is safe for the fetus. [6] Timolol is a non-selective beta blocker. [4]

Timolol was patented in 1968, and came into medical use in 1978. [7] It is on the World Health Organization's List of Essential Medicines. [8] Timolol is available as a generic medication. [4] [9] In 2023, it was the 173rd most commonly prescribed medication in the United States, with more than 2 million prescriptions. [10] [11]

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. [13]

Eye drops

In its eye drop form it is used to treat open-angle and, occasionally, secondary glaucoma. [4] [14] The mechanism of action of timolol is probably the reduction of the formation of aqueous humor [4] 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). [15] 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. [16] [17] [18] 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 [19] or prostaglandin analogs. [20]

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. [21]

On the skin

In its gel form it is used on the skin to treat infantile hemangiomas. [22]

Available forms

It is available in tablet and liquid formulations. [23] [24]

For ophthalmic use, timolol is also available combined:

Contraindications

The medication should not be taken by individuals with: [23]

Side effects

The most serious possible side effects include cardiac arrhythmias and severe bronchospasms. [23] Timolol can also lead to fainting, congestive heart failure, depression, confusion, worsening of Raynaud's syndrome and impotence. [23]

Side effects when given in the eye include: burning sensation, eye redness, superficial punctate keratopathy, corneal numbness. [24] [14]

Chemistry

The experimental log P of timolol is 1.8 and its predicted log P ranges from 0.68 to 1.8. [26] [27] [28]

Society and culture

Brand names

Timolol is sold under many brand names worldwide. [1] Timolol eye drops are sold under the brand names Timoptic and Istalol among others. [29] [30]

References

  1. 1 2 "Timolol". Drugs.com. Archived from the original on 7 March 2016. Retrieved 28 December 2016.
  2. ↑ "Product monograph brand safety updates". Health Canada. February 2024. Retrieved 24 March 2024.
  3. ↑ Volotinen M, Turpeinen M, Tolonen A, Uusitalo J, Mäenpää J, Pelkonen O (July 2007). "Timolol metabolism in human liver microsomes is mediated principally by CYP2D6". Drug Metabolism and Disposition. 35 (7): 1135–1141. doi:10.1124/dmd.106.012906. PMID   17431033. S2CID   794764.
  4. 1 2 3 4 5 6 7 8 9 10 11 "Timolol eent". The American Society of Health-System Pharmacists. Archived from the original on 28 December 2016. Retrieved 8 December 2016.
  5. 1 2 3 "Timolol Maleate". The American Society of Health-System Pharmacists. Archived from the original on 28 December 2016. Retrieved 8 December 2016.
  6. ↑ "Timolol ophthalmic Use During Pregnancy". The American Society of Health-System Pharmacists. Archived from the original on 28 December 2016. Retrieved 28 December 2016.
  7. ↑ Fischer J, Ganellin CR (2006). Analogue-based Drug Discovery. John Wiley & Sons. p. 460. ISBN   9783527607495. Archived from the original on 28 December 2016.
  8. ↑ World Health Organization (2023). The selection and use of essential medicines 2023: web annex A: World Health Organization model list of essential medicines: 23rd list (2023). Geneva: World Health Organization. hdl: 10665/371090 . WHO/MHP/HPS/EML/2023.02.
  9. ↑ "Competitive Generic Therapy Approvals". U.S. Food and Drug Administration (FDA). 29 June 2023. Archived from the original on 29 June 2023. Retrieved 29 June 2023.
  10. ↑ "Top 300 of 2023". ClinCalc. Archived from the original on 12 August 2025. Retrieved 12 August 2025.
  11. ↑ "Timolol Drug Usage Statistics, United States, 2013 - 2023". ClinCalc. Retrieved 19 August 2025.
  12. ↑ Marcus DA, Bain PA (27 February 2009). Effective Migraine Treatment in Pregnant and Lactating Women: A Practical Guide. シュプリンガー・ジャパン株式会社. pp. 141–. ISBN   978-1-60327-438-8. Archived from the original on 5 November 2017. Retrieved 14 November 2010.
  13. ↑ Atkin T, Comai S, Gobbi G (April 2018). "Drugs for Insomnia beyond Benzodiazepines: Pharmacology, Clinical Applications, and Discovery". Pharmacol Rev. 70 (2): 197–245. doi: 10.1124/pr.117.014381 . PMID   29487083. S2CID   3578916.
  14. 1 2 "Timolol Ophthalmic". MedlinePlus. 15 April 2017. Retrieved 31 December 2019.
  15. ↑ Sambhara D, Aref AA (January 2014). "Glaucoma management: relative value and place in therapy of available drug treatments". Therapeutic Advances in Chronic Disease. 5 (1): 30–43. doi:10.1177/2040622313511286. PMC   3871276 . PMID   24381726.
  16. ↑ Liu JH, Kripke DF, Weinreb RN (September 2004). "Comparison of the nighttime effects of once-daily timolol and latanoprost on intraocular pressure". American Journal of Ophthalmology. 138 (3): 389–95. doi:10.1016/j.ajo.2004.04.022. PMID   15364220.
  17. ↑ Liu JH, Medeiros FA, Slight JR, Weinreb RN (March 2009). "Comparing diurnal and nocturnal effects of brinzolamide and timolol on intraocular pressure in patients receiving latanoprost monotherapy". Ophthalmology. 116 (3): 449–54. doi:10.1016/j.ophtha.2008.09.054. PMID   19157559.
  18. ↑ Liu JH, Slight JR, Vittitow JL, Scassellati Sforzolini B, Weinreb RN (September 2016). "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. doi: 10.1016/j.ajo.2016.04.019 . PMID   27457257.
  19. ↑ Strohmaier K, Snyder E, Adamsons I (July 1998). "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. PMID   9697378.
  20. ↑ "Ganfort 0.3 mg/ml + 5 mg/ml eye drops, solution - Summary of Product Characteristics (SmPC)". (emc). 20 February 2020. Retrieved 1 March 2020.
  21. ↑ Sena DF, Lindsley K (January 2017). "Neuroprotection for treatment of glaucoma in adults". The Cochrane Database of Systematic Reviews. 1 (1): CD006539. doi:10.1002/14651858.CD006539.pub4. PMC   5370094 . PMID   28122126.
  22. ↑ Novoa M, Baselga E, Beltran S, Giraldo L, Shahbaz A, Pardo-Hernandez H, et al. (April 2018). "Interventions for infantile haemangiomas of the skin". The Cochrane Database of Systematic Reviews. 2018 (4): CD006545. doi:10.1002/14651858.CD006545.pub3. PMC   6513200 . PMID   29667726.
  23. 1 2 3 4 "Timolol Maleate tablet". DailyMed. 17 August 2006. Retrieved 1 December 2019.
  24. 1 2 "Betimol- timolol solution". DailyMed. 18 March 2010. Retrieved 1 December 2019.
  25. ↑ "Package leaflet: Information for the user Timolol" (PDF). hpra.ie. Archived from the original (PDF) on 16 August 2018. Retrieved 15 August 2018.
  26. ↑ "Timolol | C13H24N4O3S | CID 33624 - PubChem". pubchem.ncbi.nlm.nih.gov. Retrieved 2 August 2025.
  27. ↑ "(−)-S-Timolol". ChemSpider. 10 June 2024. Retrieved 10 July 2025.
  28. ↑ "Timolol: Uses, Interactions, Mechanism of Action". DrugBank Online. 31 December 1994. Retrieved 10 July 2025.
  29. ↑ "Generic Istalol Availability". Drugs.com . Retrieved 20 June 2019.
  30. ↑ "Istalol". Drugs.com. 1 August 2018. Retrieved 19 July 2019.
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