Timolol
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| Clinical data | |
|---|---|
| Trade names | Many names worldwide[1] |
| AHFS/Drugs.com | Monograph |
| MedlinePlus | a602022 |
| Pregnancy category |
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| Routes of administration |
By mouth, topical (eye drop) |
| ATC code | C07AA06 (WHO) S01ED01 (WHO) |
| Legal status | |
| Legal status |
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| Pharmacokinetic data | |
| Bioavailability | 60% |
| Metabolism | Liver (80%) |
| Biological half-life | 2.5–5 hours |
| Excretion | Renal |
| Identifiers | |
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| CAS Number | 26839-75-8  |
| PubChem (CID) | 33624 |
| IUPHAR/BPS | 565 |
| DrugBank | DB00373 |
| ChemSpider | 31013 |
| UNII | 5JKY92S7BR |
| KEGG | D08600 |
| ChEBI | CHEBI:9599 |
| ChEMBL | CHEMBL499 |
| ECHA InfoCard | 100.043.651 |
| Chemical and physical data | |
| Formula | C13H24N4O3S |
| Molar mass | 316.421 g/mol |
| 3D model (Jmol) | Interactive image |
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Timolol is a non-selective β adrenergic receptor antagonist indicated for treating glaucoma, heart attacks, hypertension, and migraine headache.
It is on the World Health Organization's List of Essential Medicines, the most important medications needed in a basic health system.[2]
Medical uses[edit]
In its by mouth form, it is used:
- to treat high blood pressure
- to prevent heart attacks
- to prevent migraine headaches[3]
In its eye drop form it is used to treat open-angle and, occasionally, secondary glaucoma by reducing aqueous humour production through blockage of the β receptors on the ciliary epithelium. The pharmacological mechanism by which it actually does this is still unknown. It was the first β blocker approved for topical use in treatment of glaucoma in the USA (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 patients. That is, tolerance develops. It may reduce the extent of diurnal IOP curve up to 50%. IOP higher during sleep. 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.[4]
A Cochrane Systematic Review compared the effect of timolol versus brimonidine in slowing the progression of open angle glaucoma in adult participants.[5]
Side effects[edit]
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.
Formulations[edit]
It is available in tablet and liquid formulations.
For ophthalmic use, timolol is also available combined:
- with carbonic anhydrase inhibitors:
- timolol and brinzolamide
- timolol and dorzolamide
- with α2 agonists:
- with prostaglandin analogs:
- timolol and latanoprost
- timolol and travoprost
Brand names[edit]
Timolol is marketed under many trade names worldwide.[1]
References[edit]
- ^ a b Drugs.com International trade names for timolol Page accessed Feb 26, 2016
- ^ "WHO Model List of EssentialMedicines" (PDF). World Health Organization. October 2013. Retrieved 22 April 2014.
- ^ Dawn A. Marcus; Philip A. Bain (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. Retrieved 14 November 2010.
- ^ Strohmaier, K; Snyder, E; Adamsons, I (Jul 1998). "A multicenter study comparing dorzolamide and pilocarpine as adjunctive therapy to timolol: patient preference and impact on daily life". J Am Optom Assoc. 69 (7): 441–51. PMID 9697378.
- ^ Sena DF, Lindsley K (2013). "Neuroprotection for treatment of glaucoma in adults". Cochrane Database Syst Rev. 2 (2): CD006539. doi:10.1002/14651858.CD006539.pub3. PMC 4261923
. PMID 23450569.
External links[edit]
- Weinstock, Leonard M.; Mulvey, Dennis M.; Tull, Roger. (1976). "Synthesis of the .beta.-adrenergic blocking agent timolol from optically active precursors". The Journal of Organic Chemistry. 41 (19): 3121–3124. doi:10.1021/jo00881a011. PMID 9497.
