timolol (Blocadren, Timoptic, Betimol, Istalol)
Jump to navigation
Jump to search
Introduction
Tradename: Blocadren.
Indications
- ophthalmic agent:
- systemic agent ?
Contraindications
Caution:
- uncompensated congestive heart failure
- bradycardia
- severe COPD
Dosage
Timoptic (timolol maleate): 0.25% & 0.5% 5,10 & 15 mL
Istolol (timolol maleate): 0.5%
Betimol (timolol hemihydrate:) 0.25% & 0.5% 5,10 & 15 mL
Timoptic XE
Pharmacokinetics
- intraocular pressure reduction within 15-30 minutes
- maximal reduction in 1-5 hours
- duration of action: 24 hours
- metabolized in the liver by cyt P450 2D6
elimination via liver
elimination via kidney
1/2life = 3.0-5.2 hours
protein binding = 60 %
elimination by hemodialysis = -
Adverse effects
- ophthalmic agent:
- not common (1-10%)
- uncommon (< 1%)
- hallucinations[9][10]
- significant blood levels with ophthalmic agent[6]
- see oral (systemic) administration
- oral (systemic) administration)
- common (> 10%)
- less common (1-10%)
- bradycardia, arrhythmia, reduced peripheral circulation, dizziness, fatigue, itching, weakness, burning eyes, stinging eyes, dyspnea
- uncommon (< 1%)
- chest pain, congestive heart failure, hallucinations, mental depression, anxiety, nightmares, rash, diarrhea, nausea/vomiting, epeigastric discomfort, numbness in toes & fingers, dry sore eyes
* according to ref[11] timolol causes more orthostatic hypotension than brimonidine
- drug adverse effects of beta-adrenergic receptor antagonists
- drug adverse effects of renin-angiotensin-aldosterone system inhibitors (RAAS inhibitors)
- drug adverse effects of antihypertensive agents
Drug interactions
- phenothiazine & cimetidine may decrease plasma levels
- any drug that inhibits cyt P450 2D6 may increase levels of timolol
- drug interaction(s) of beta-2 adrenergic receptor agonists with beta adrenergic receptor antagonists
- drug interaction(s) of renin-angiotensin-aldosterone inhibitors with trimethoprim-sulfamethoxazole
- drug interaction(s) of beta-adrenergic receptor antagonists with thyroid hormone
- drug interaction(s) of beta-adrenergic receptor antagonists with sulfinpyrazone
- drug interaction(s) of beta-adrenergic receptor antagonists with salicylate
- drug interaction(s) of beta-adrenergic receptor antagonists with rifampin
- drug interaction(s) of beta-adrenergic receptor antagonists with ampicillin
- drug interaction(s) of beta-adrenergic receptor antagonists with colestipol
- drug interaction(s) of beta-adrenergic receptor antagonists with cholestyramine
- drug interaction(s) of beta-adrenergic receptor antagonists with barbiturates
- drug interaction(s) of beta-adrenergic receptor antagonists with calcium salts
- drug interaction(s) of beta-adrenergic receptor antagonists with aluminum carbonate
- drug interaction(s) of beta-adrenergic receptor antagonists with aluminum hydroxide
- drug interaction(s) of beta-adrenergic receptor antagonists with prazosin
- drug interaction(s) of beta-adrenergic receptor antagonists with lidocaine
- drug interaction(s) of beta-adrenergic receptor antagonists with ergot alkaloids
- drug interaction(s) of beta-adrenergic receptor antagonists with clonidine
- drug interaction(s) of beta-adrenergic receptor antagonists with benzodiazepines
- drug interaction(s) of beta-adrenergic receptor antagonists (except atenolol) with benzodiazepines
- drug interaction(s) of beta-adrenergic receptor antagonists with quinolones
- drug interaction(s) of beta-adrenergic receptor antagonists with quinidine
- drug interaction(s) of beta-adrenergic receptor antagonists with propafenone
- drug interaction(s) of beta-adrenergic receptor antagonists with phenothiazines
- drug interaction(s) of beta-adrenergic receptor antagonists with MAO inhibitors
- drug interaction(s) of beta-adrenergic receptor antagonists with loop diuretics
- drug interaction(s) of beta-adrenergic receptor antagonists with hydralazine
- drug interaction(s) of beta-adrenergic receptor antagonists with histamine H2 receptor antagonists
- drug interaction(s) of beta-adrenergic receptor antagonists with haloperidol
- drug interaction(s) of beta-adrenergic receptor antagonists with flecainide
- drug interaction(s) of beta-adrenergic receptor antagonists with oral contraceptives
- drug interaction(s) of beta-adrenergic receptor antagonists with calcium channel blockers
- drug interaction(s) of beta-adrenergic receptor antagonists with sulfonylureas
- drug interaction(s) of beta blockers with ACE inhibitors
- drug interaction(s) of spironolactone with beta blockers
- drug interaction(s) of NSAIDs with beta blockers
- drug interaction(s) of NSAIDs & antihypertensives
Laboratory
- specimen: serum, plasma (EDTA, heparin)
- methods: TLC, GC, HPLC
- no good correlation of plasma levels with therapeutic effect
Mechanism of action
- reduction aqueous humor formation in the ciliary body in the eye
- depresses intraocular pressure 18-34% within first few treatments
- owever, there are short-term escape & long-term drift effects in some patients, i.e., tolerance develops
- efficacy of timolol in lowering intraocular pressure during sleep may be limited[8]
More general terms
Additional terms
Component of
- dorzolamide/timolol (Cosopt)
- brimonidine/timolol
- hydrochlorothiazide/timolol; HCTZ/timolol (Timolide)
References
- ↑ The Pharmacological Basis of Therapeutics, 9th ed. Gilman et al, eds. Permagon Press/McGraw Hill, 1996
- ↑ Drug Information & Medication Formulary, Veterans Affairs, Central California Health Care System, 1st ed., Ravnan et al eds, 1998
- ↑ Kaiser Permanente Northern California Regional Drug Formulary, 1998
- ↑ Clinical Guide to Laboratory Tests, NW Tietz (ed) 3rd ed, WB Saunders, Philadelpha 1995
- ↑ Prescriber's Letter 13(3): 2006 Cytochrome P450 drug interactions Detail-Document#: http://prescribersletter.com/(5bhgn1a4ni4cyp2tvybwfh55)/pl/ArticleDD.aspx?li=1&st=1&cs=&s=PRL&pt=3&fpt=25&dd=220233&pb=PRL (subscription needed) http://www.prescribersletter.com
- ↑ 6.0 6.1 Prescriber's Letter 17(3): 2010 PATIENT HANDOUT: How to Use Eyedrops COMMENTARY: Systemic Effects of Ophthalmic Beta-Blockers PATIENT HANDOUT SPANISH VERSION: Como usar las gotas para los ojos Detail-Document#: http://prescribersletter.com/(5bhgn1a4ni4cyp2tvybwfh55)/pl/ArticleDD.aspx?li=1&st=1&cs=&s=PRL&pt=3&fpt=25&dd=260309&pb=PRL (subscription needed) http://www.prescribersletter.com
- ↑ 7.0 7.1 bacterial infections due to susceptible organisms
- ↑ 8.0 8.1 Wikipedia: Timolol https://en.wikipedia.org/wiki/Timolol
- ↑ 9.0 9.1 Cimolai N. Neuropsychiatric adverse events from topical ophthalmic timolol. Clin Med Res. 2019;17(3-4):90-96 <PubMed> PMID: https://www.ncbi.nlm.nih.gov/pubmed/31462538 PMCID: PMC6886891 Free PMC article <Internet> http://www.clinmedres.org/content/17/3-4/90
- ↑ 10.0 10.1 Negri L, Ferreras A, Iester M. Timolol 0.1% in glaucomatous patients: efficacy, tolerance, and quality of life. J Ophthalmol. 2019 May 2;2019:4146124 PMID: https://www.ncbi.nlm.nih.gov/pubmed/31191995 PMCID: PMC6525866 Free PMC article https://www.hindawi.com/journals/joph/2019/4146124/
- ↑ 11.0 11.1 11.2 NEJM Knowledge+ Ophthalmology
Database
- PubChem: http://pubchem.ncbi.nlm.nih.gov/summary/summary.cgi?cid=5478
- PubChem: http://pubchem.ncbi.nlm.nih.gov/summary/summary.cgi?cid=62933
- PubChem: http://pubchem.ncbi.nlm.nih.gov/summary/summary.cgi?cid=62932
- PubChem: http://pubchem.ncbi.nlm.nih.gov/summary/summary.cgi?cid=33624
- PubChem: http://pubchem.ncbi.nlm.nih.gov/summary/summary.cgi?cid=5281056