Timolol is available in which concentrations?

• A. 0.1% and 0.5%
• B. 0.5% and 0.25%
• C. 1% and 0.5%
• D. 0.75% and 0.25%

Answer: (B)

Timolol ophthalmic solution is available in two standard strengths: 0.25% and 0.5%. These concentrations are used because timolol lowers intraocular pressure by reducing aqueous humor production, and having two common strengths gives clinicians flexibility to tailor therapy. The 0.5% formulation is the usual, widely used option, while 0.25% provides a lower-dose alternative for patients who may need less exposure or who might be more susceptible to systemic or local side effects. Higher or lower nonstandard concentrations, such as 1% or other uncommon strengths, aren’t typical ophthalmic formulations for timolol. Thus, the pair 0.5% and 0.25% is correct.