Timolol

Overview

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.[1][2] WP

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. 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 chronic obstructive pulmonary disease (COPD). It is unclear if use during pregnancy is safe for the fetus. Timolol is a non-selective beta blocker.[1][2][3] WP

Timolol was patented in 1968, and came into medical use in 1978. It is on the World Health Organization's List of Essential Medicines. Timolol is available as a generic medication. In 2023, it was the 173rd most commonly prescribed medication in the United States, with more than 2 million prescriptions.[1][4–8] WP

Drug class

Beta blocker WP

From the Wikipedia article's infobox.

Uses, dosage and effects

By mouth

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

• to treat high blood pressure WP
• to prevent heart attacks WP
• to prevent migraine headaches[9] WP

The combination of timolol and the alpha-1 blocker prazosin has sedative effects.[10] WP

Eye drops

In its eye drop form it is used to treat open-angle and, occasionally, secondary glaucoma. 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). 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. 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 or prostaglandin analogs.[1][11–17] WP

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] WP

On the skin

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

Available forms

It is available in tablet and liquid formulations.[20][21] WP

For ophthalmic use, timolol is also available combined: WP

• with carbonic anhydrase inhibitors: WP
• timolol and brinzolamide WP
• timolol and dorzolamide WP
• with α₂ agonists: WP
• timolol and brimonidine WP
• with prostaglandin analogs: WP
• timolol and latanoprost WP
• timolol and travoprost WP

Risks and side effects

Contraindications

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

• An allergy to timolol or any other beta-blockers[20] WP
• Asthma or severe chronic obstructive bronchitis[20] WP
• A slow heart rate (bradycardia), or a heart block[20] WP
• Heart failure[22] WP

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.[20] WP

Side effects when given in the eye include: burning sensation, eye redness, superficial punctate keratopathy, corneal numbness.[11][21] WP

Legal status

Brand names

Timolol is sold under many brand names worldwide. Timolol eye drops are sold under the brand names Timoptic and Istalol among others.[23][24][25] WP

Chemistry

Formula

C13H24N4O3S PC

CAS number

26839-75-8 PC

Molar mass (g/mol)

316.42 PC

IUPAC name (computed by PubChem)

(2S)-1-(tert-butylamino)-3-[(4-morpholin-4-yl-1,2,5-thiadiazol-3-yl)oxy]propan-2-ol PC

SMILES

CC(C)(C)NC[C@@H](COC1=NSN=C1N2CCOCC2)O PC

InChIKey

BLJRIMJGRPQVNF-JTQLQIEISA-N PC

PubChem CID

33624

Harm reduction information

No harm reduction data is on file for this compound yet. That means no dose, timing or combination data from PsychonautWiki or TripSit. Please don't guess a dose from similar compounds. If you have taken it and feel unwell, contact emergency services or a poison control center.

User reports

Pop culture

No references added yet.

Sources

1. Other Timolol eent
2. Other Timolol Maleate
3. Other Timolol ophthalmic Use During Pregnancy
4. Other Fischer J, Ganellin CR. Analogue-based Drug Discovery. 2006
5. Other The selection and use of essential medicines 2023: web annex A: World Health Organization model list of essential medicines: 23rd list (2023). 2023
6. Journal / agency Competitive Generic Therapy Approvals. 29 June 2023
7. Other Top 300 of 2023
8. Other Timolol Drug Usage Statistics, United States, 2014 - 2023
9. Other Marcus DA, Bain PA. Effective Migraine Treatment in Pregnant and Lactating Women: A Practical Guide. 27 February 2009
10. Journal / agency Atkin T, Comai S, Gobbi G. Drugs for Insomnia beyond Benzodiazepines: Pharmacology, Clinical Applications, and Discovery. Pharmacol Rev. April 2018. doi:10.1124/pr.117.014381 · PMID 29487083
11. Journal / agency Timolol Ophthalmic. 15 April 2017
12. Journal / agency Sambhara D, Aref AA. Glaucoma management: relative value and place in therapy of available drug treatments. Therapeutic Advances in Chronic Disease. January 2014. doi:10.1177/2040622313511286 · PMID 24381726 · PMC3871276
13. Journal / agency Liu JH, Kripke DF, Weinreb RN. Comparison of the nighttime effects of once-daily timolol and latanoprost on intraocular pressure. American Journal of Ophthalmology. September 2004. doi:10.1016/j.ajo.2004.04.022 · PMID 15364220
14. Journal / agency 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. March 2009. doi:10.1016/j.ophtha.2008.09.054 · PMID 19157559
15. Journal / agency 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. September 2016. doi:10.1016/j.ajo.2016.04.019 · PMID 27457257
16. Journal / agency 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. July 1998. PMID 9697378
17. Other Ganfort 0.3 mg/ml + 5 mg/ml eye drops, solution - Summary of Product Characteristics (SmPC). 20 February 2020
18. Journal / agency Sena DF, Lindsley K. Neuroprotection for treatment of glaucoma in adults. The Cochrane Database of Systematic Reviews. January 2017. doi:10.1002/14651858.CD006539.pub4 · PMID 28122126 · PMC5370094
19. Journal / agency 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. April 2018. doi:10.1002/14651858.CD006545.pub3 · PMID 29667726 · PMC6513200
20. Journal / agency Timolol Maleate tablet. 17 August 2006
21. Journal / agency Betimol- timolol solution. 18 March 2010
22. Other Package leaflet: Information for the user Timolol
23. Other Timolol
24. Other Generic Istalol Availability
25. Other Istalol. 1 August 2018

Text and values on this page are quoted from Wikipedia (CC BY-SA 4.0), PubChem (public domain). Each value links to the exact revision it came from.