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Timolol Maleate

It is one of the most common and oldest β blockers available. It is a non selective β blocker. It acts directly on the ciliary epithelium to reduce aqueous production. It lowers IOP both in normal and ocular hypertensive patients.


The drug can lower IOP in the untreated contralateral eye because of systemic absorption which is known as cross over effect.
Timolol penetrates the eye rapidly and its effect is seen in 30 to 60 minutes and lasts upto 24- 48 hours.
Short term escape: The initial dose of timolol produces the maximum effect about 40% or more, followed by a partial decline over the following days or weeks. This may be due to alterations in the β adrenergic receptors in the ocular tissues may be an increase in the no of receptors. The best time to evaluate the effect it is after 1 month.
Long term drift: The IOP slowly increases over a period of time in patients who have well controlled IOP. This may be due to partial adaptation of the ciliary body to long term administration of timolol may be due to decrease in cellular sensitivity.

Preparation & Dosage:

It is available in 0.25% and 0.5%. Administered  once or twice daily. Maximum action takes place by 2 hours. The washout period for timolol is 14 hours.
It is also available as a gel format applied once daily. It comes in 0.5% concentration. It is more effective with light colors than dark color iris, may be due to its binding effect with melanin. It reduces IOP by 25 to 30%.
Additive effect with other drugs: Pilocarpine and CAIs have an additive effect, where as there is a very small additive effect with epinephrine.

Uses :

The β adrenergic blockers are useful in all types of glaucomas. They are better tolerated by patients and they don't affect the pupil or the accommodation.

Side effects


Nervous system: Depression, Anxiety, Confusion, Hallucination, Fatigue, Tinnitus, Abnormal taste sensation, Diplopia, Lightheadedness, Cerebrovascular accidents, Psycosis.
Cardiovascular: Bradycardia, Heart failure, Arrhythmia, Raynaud's phenomenon, Hypotension, Hypertension, Syncope, MI, Death.
Pu1monary: Dyspnea, Airway obstruction, pulmonary failure, Apnea especially in children (sleep).
Gastrointestinal: Nausea, Vomiting, Diarrhea, Abdominal cramps

Statutory Warning

Materials / Informations provided here are for educational purpose only ; and not to be used for medical advice, diagnosis or treatment