Purpose: The authors analyzed the actual length of use of commercially
available 5-ml bottles of 0.5% timolol maleate (Timoptic) and 0.5% le
vobunolol (Betagan) among patients who routinely use topical beta-bloc
kers (1 drop twice daily in both eyes) for glaucoma treatment. Methods
: Patients were randomized to receive two 5-ml bottles of either timol
ol or levobunolol in a double-blind fashion. The patients used the dro
ps independently and the bottles in sequence. The dates were recorded
when each of the two 5-ml bottles were used. Sixty patients were enrol
led, 15 were excluded from the study, and the data from the remaining
45 were analyzed. Results: There was a 21% greater length of use per 5
-ml bottle among patients who were randomized to 0.5% timolol maleate
(36.6 +/- 10.4 days) compared with 0.5% levobunolol (28.9 +/- 8.1 days
) (P = 0.009). The length of use of the first bottle versus the second
bottle was compared and was found not to be significantly different i
n either group. There was no statistical difference in intraocular pre
ssure control among patients before and after the study. Conclusion: T
here is a markedly greater length of use of the 5-ml bottle of timolol
compared with the 5-ml bottle of levobunolol. The difference is belie
ved to be due to the configuration of the levobunolol's bottle tip and
the vehicle used to deliver the drug. The data may be extrapolated to
a substantial patient savings and should be considered in prescriptio
n recommendations.