Timolol

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Image:Timolol.png
Timolol
Systematic (IUPAC) name
(S)-1-(tert-butylamino)- 3-(4-morpholino-1,2,5-thiadiazol-3-yloxy)propan-2-ol
Identifiers
CAS number	26839-75-8
ATC code	C07 AA06
PubChem	5478
DrugBank	APRD00229
Chemical data
Formula	C₁₃H₂₄N₄O₃S
Mol. weight	316.421 g/mol
Pharmacokinetic data
Bioavailability	60%
Metabolism	Hepatic: 80%
Half life	2.5-5 hours
Excretion	Renal
Therapeutic considerations
Pregnancy cat.	C(AU) C(US)
Legal status	℞ Prescription only
Routes	oral, Ophthalmic

Timolol maleate is a non-selective beta-adrenergic receptor blocker. In its oral form (Blocadren®), it is used to treat high blood pressure and prevent heart attacks, and occasionally to prevent migraine headaches. In its ophthalmic form (brand names Timoptol® in Italy; Timoptic®), it is used to treat open-angle and occasionally secondary glaucoma by reducing aqueous humour production through blockade of the beta receptors on the ciliary epithelium.

1 Side effects
2 Usual Dosage
3 Formulations
4 Brand Names

[edit] Side effects

The most serious possible side effects include cardiac arrhythmias and severe bronchospasms. Timolol can also lead to fainting, stroke, congestive heart failure, depression, confusion, and impotence.

[edit] Usual Dosage

Children and Adults: Ophthalmic: Initial: 0.25% solution, instill 1 drop twice daily; increase to 0.5% solution if response not adequate; decrease to 1 drop/day if *controlled; do not exceed 1 drop twice daily of 0.5% solution Adults: Oral:
Hypertension: Initial: 10 mg twice daily, increase gradually every 7 days, usual dosage: 20-40 mg/day in 2 divided doses; maximum: 60 mg/day
Prevention of myocardial infarction: 10 mg twice daily initiated within 1-4 weeks after infarction
Migraine headache: Initial: 10 mg twice daily, increase to maximum of 30 mg/day

[edit] Formulations

Gel-forming solution, ophthalmic, as maleate (Timoptic-XE®): 0.25% (2.5 mL, 5 mL); 0.5% (2.5 mL, 5 mL)
Solution, ophthalmic, as hemihydrate (Betimol®): 0.25% (5 mL, 10 mL, 15 mL); 0.5% (5 mL, 10 mL, 15 mL) [contains benzalkonium chloride]
Solution, ophthalmic, as maleate: 0.25% (5 mL, 10 mL, 15 mL); 0.5% (5 mL, 10 mL, 15 mL) [contains benzalkonium chloride]
Timoptic®: 0.25% (5 mL, 10 mL); 0.5% (5 mL, 10 mL) [contains benzalkonium chloride]
Solution, ophthalmic, as maleate [preservative free] (Timoptic® OcuDose®): 0.25% (0.2 mL);0.5% (0.2 mL) [single use]
Tablet, as maleate (Blocadren®): 5 mg, 10 mg, 20 mg

[edit] Brand Names

In Canada Apo®-Timol, Apo®-Timop, Gen-Timolol®, Nu-Timolol®, Phoxal-timolol®, PMS-Timolol®, Tim-AK®. In United States Betimol®, Blocadren®, Istalol®, Timoptic® OcuDose®. In both Canada and US: Timoptic® and Timoptic-XE®.

Beta blockers (C07) edit

Non-selective β antagonists (C07AA) edit
Metipranolol, Nadolol, Oxprenolol, Penbutolol, Pindolol, Propranolol, Timolol, Sotalol

β₁ antagonists (cardioselective) (C07AB) edit
Atenolol, Acebutolol, Betaxolol, Bisoprolol, Esmolol, Metoprolol, Nebivolol

Mixed α₁/β antagonists (C07AG) edit
Carvedilol, Labetalol

Antiglaucoma preparations and miotics (S01E) edit
Sympathomimetics:	Apraclonidine, Brimonidine, Clonidine, Dipivefrine, Epinephrine
Parasympathomimetics:	Aceclidine, Acetylcholine, Carbachol, Demecarium, Echothiophate, Fluostigmine, Neostigmine, Paraoxon, Physostigmine, Pilocarpine
Carbonic anhydrase inhibitors:	Acetazolamide, Brinzolamide, Diclofenamide, Dorzolamide, Methazolamide
Beta blocking agents:	Befunolol, Betaxolol, Carteolol, Levobunolol, Metipranolol, Timolol
Prostaglandin analogues:	Bimatoprost, Latanoprost, Travoprost, Unoprostone
Other agents:	Dapiprazole, Guanethidine