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Timolol



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 C07AA06
PubChem 5478
DrugBank APRD00229
Chemical data
Formula C13H24N4O3S 
Mol. mass 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.

Additional recommended knowledge

Contents

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, and impotence.

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

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

For opthalmic use, timolol is also available combined with other medications:

Brand names

  • In Canada: Apo-Timol, Apo-Timop, Gen-Timolol, Nu-Timolol, Phoxal-timolol, PMS-Timolol, Tim-AK, Timoptic, Timoptic-XE.
  • In United States: Betimol, Blocadren, Istalol, Timoptic, Timoptic-XE, Timoptic OcuDose.
 
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Timolol". A list of authors is available in Wikipedia.
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