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Timolol

Timolol
Timolol structure.svg
Timolol ball-and-stick.png
Clinical data
Trade namesBetimol, Istalol, others[1]
AHFS/Drugs.comMonograph
MedlinePlusa684029
License data
Pregnancy
category
  • AU: C
  • US: C (Risk not ruled out)
Routes of
administration
By mouth, topical (eye drop)
Drug classBeta blocker
ATC code
Legal status
Legal status
Pharmacokinetic data
Bioavailability60%
MetabolismLiver (80%)
Elimination half-life2.5–5 hours
ExcretionKidney
Identifiers
CAS Number
PubChem CID
IUPHAR/BPS
DrugBank
ChemSpider
UNII
KEGG
ChEBI
ChEMBL
CompTox Dashboard (EPA)
ECHA InfoCard100.043.651 Edit this at Wikidata
Chemical and physical data
FormulaC13H24N4O3S
Molar mass316.421 g/mol g·mol−1
3D model (JSmol)
  (verify)

Timolol is a medication used either by mouth or as eye drops.[2][3] As eye drops it is used to treat increased pressure inside the eye such as in ocular hypertension and glaucoma.[2] 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.[2] 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.[2] Use is not recommended in those with asthma, uncompensated heart failure, or COPD.[2] It is unclear if use during pregnancy is safe for the baby.[4] Timolol is a non-selective beta blocker.[2]

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, the safest and most effective medicines needed in a health system.[6] Timolol is available as a generic medication.[2] The wholesale cost in the developing world is about US$0.86–2.29 per 5 ml bottle.[7] In the United States it costs US$25–50 per month.[8] In 2017, it was the 146th most commonly prescribed medication in the United States, with more than four million prescriptions.[9][10]

Medical uses

By mouth

In its by mouth form, it is used:

Eye drops

In its eye drop form it is used to treat open-angle and, occasionally, secondary glaucoma.[2][12] The mechanism of action of timolol is probably the reduction of the formation of aqueous humor[2] 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).[13] 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 diurnal IOP curve up to 50%. IOP higher during sleep. Efficacy of timolol in lowering IOP during the sleep period may be limited.[14][15][16] It is 5–10× more potent β blocker than propranolol. Timolol is light-sensitive; it is usually preserved with 0.01% benzalkonium chloride (BAC), but also comes BAC-free. Can also be used in adjunctive therapy with pilocarpine or carbonic anhydrase inhibitors.[17]

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.[18]

On the skin

In its gel form it is used on the skin to treat infantile hemangiomas.[19]

Contraindications

The medication should not be taken by individuals with:[20]

Side effects

The most serious possible side effects include cardiac arrhythmias and severe bronchospasms.[20] Timolol can also lead to fainting, congestive heart failure, depression, confusion, worsening of Raynaud's syndrome and impotence.[20]

Side effects when given in the eye include: burning sensation, eye redness, superficial punctate keratopathy, corneal numbness.[22][12]

Formulations

It is available in tablet and liquid formulations.[20][22]

For ophthalmic use, timolol is also available combined:

Brand names

Timolol is marketed under many trade names worldwide.[1] Timolol eye drops are marketed under the brand name Istalol among others.[23][24]

References

  1. ^ a b "Timolol". Drugs.com. Archived from the original on 7 March 2016. Retrieved 28 December 2016.
  2. ^ a b c d e f g h i "Timolol eent". The American Society of Health-System Pharmacists. Archived from the original on 28 December 2016. Retrieved 8 December 2016.
  3. ^ a b c "Timolol Maleate". The American Society of Health-System Pharmacists. Archived from the original on 28 December 2016. Retrieved 8 December 2016.
  4. ^ "Timolol ophthalmic Use During Pregnancy". The American Society of Health-System Pharmacists. Archived from the original on 28 December 2016. Retrieved 28 December 2016.
  5. ^ Fischer J, Ganellin CR (2006). Analogue-based Drug Discovery. John Wiley & Sons. p. 460. ISBN 9783527607495. Archived from the original on 28 December 2016.
  6. ^ World Health Organization (2019). World Health Organization model list of essential medicines: 21st list 2019. Geneva: World Health Organization. hdl:10665/325771. WHO/MVP/EMP/IAU/2019.06. License: CC BY-NC-SA 3.0 IGO.
  7. ^ "Timolol Maleate". International Drug Price Indicator Guide. Retrieved 8 December 2016.
  8. ^ Hamilton R (2015). Tarascon Pocket Pharmacopoeia 2015 Deluxe Lab-Coat Edition. Jones & Bartlett Learning. p. 411. ISBN 9781284057560.
  9. ^ "The Top 300 of 2020". ClinCalc. Retrieved 11 April 2020.
  10. ^ "Timolol - Drug Usage Statistics". ClinCalc. Retrieved 11 April 2020.
  11. ^ 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.
  12. ^ a b "Timolol Ophthalmic". MedlinePlus. 15 April 2017. Retrieved 31 December 2019.
  13. ^ 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.
  14. ^ Liu JH, Kripke DF, Weinreb RN (September 2004). "Comparison of the nocturnal 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.
  15. ^ 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.
  16. ^ 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.
  17. ^ 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.
  18. ^ 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.
  19. ^ Novoa M, Baselga E, Beltran S, Giraldo L, Shahbaz A, Pardo-Hernandez H, Arevalo-Rodriguez I (April 2018). "Interventions for infantile haemangiomas of the skin". The Cochrane Database of Systematic Reviews. 4: CD006545. doi:10.1002/14651858.CD006545.pub3. PMC 6513200. PMID 29667726.
  20. ^ a b c d "Timolol Maleate tablet". DailyMed. 17 August 2006. Retrieved 1 December 2019.
  21. ^ "Package leaflet: Information for the user Timolol" (PDF). hpra.ie.
  22. ^ a b "Betimol- timolol solution". DailyMed. 18 March 2010. Retrieved 1 December 2019.
  23. ^ "Generic Istalol Availability". Drugs.com. Retrieved 20 June 2019.
  24. ^ "Istalol". Drugs.com. 1 August 2018. Retrieved 19 July 2019.

External links

  • "Timolol". Drug Information Portal. U.S. National Library of Medicine.
  • "Timolol Ophthalmic". Drug Information Portal. U.S. National Library of Medicine.