Product Information
Registration Status: ActiveTIMOPTOL OPHTHALMIC SOLUTION 0.5% is approved to be sold in Singapore with effective from 1990-04-20. It is marketed by SANTEN PHARMACEUTICAL ASIA PTE LTD, with the registration number of SIN04135P.
This product contains Timolol 0.50% in the form of SOLUTION. It is approved for OPHTHALMIC use.
This product is manufactured by Santen Pharmaceutical Co. in JAPAN.
It is a Prescription Only Medicine that can only be obtained from a doctor or a dentist, or a pharmacist with a prescription from a Singapore-registered doctor or dentist.
Description
A beta-adrenergic antagonist similar in action to propranolol. The levo-isomer is the more active. Timolol has been proposed as an antihypertensive, antiarrhythmic, antiangina, and antiglaucoma agent. It is also used in the treatment of migraine disorders and tremor. [PubChem]
Indication
In its oral form it is used to treat high blood pressure and prevent heart attacks, and occasionally to prevent migraine headaches. In its opthalmic form it is used to treat open-angle and occasionally secondary glaucoma.
Mechanism of Action
Like propranolol and nadolol, timolol competes with adrenergic neurotransmitters such as catecholamines for binding at beta(1)-adrenergic receptors in the heart and vascular smooth muscle and beta(2)-receptors in the bronchial and vascular smooth muscle. Beta(1)-receptor blockade results in a decrease in resting and exercise heart rate and cardiac output, a decrease in both systolic and diastolic blood pressure, and, possibly, a reduction in reflex orthostatic hypotension. Beta(2)-blockade results in an increase in peripheral vascular resistance. The exact mechanism whereby timolol reduces ocular pressure is still not known. The most likely action is by decreasing the secretion of aqueous humor.
Pharmacokinetics
- Absorption
- Bioavailability is about 60%
- Distribution
- Metabolism
- Primarily hepatic (80%) via the cytochrome P450 2D6 isoenzyme.
- Elimination
Toxicity
LD50=1190 mg/kg (oral, mice), LD50=900 mg/kg (oral, rat). Symptoms of overdose include drowsiness, vertigo, headache, and atriventricular block.
Active Ingredient/Synonyms
(S)-1-(tert-butylamino)-3-[(4-morpholin-4-yl-1,2,5-thiadiazol-3-yl)oxy]propan-2-ol | Timolol | Timolol anhydrous | Timololo | Timololum | Timolol |
Source of information: Drugbank (External Link). Last updated on: 3rd July 18. *Trade Name used in the content below may not be the same as the HSA-registered product.