Timolol also causes drowsiness then why's that not the answer? (Timolol also crosses the BBB)

Timolol also causes drowsiness then why’s that not the answer? (Timolol also crosses the BBB)

Brimonidine is classically associated with drowsiness.

It can also cause infant apnea.

Crossing of BBB is not only important na; the mechanism of brimonidine is different from timolol so it can cause CNS depresssion.

what does the mechanism of action have to do with drowsiness? Brim acts on alpha 2 and tim on beta rec…

Brimonidine is central sympatholytic thus reduced sympathetic outflow thus CNS depression, Timolol is peripheral Beta blocker

Drowsiness or Sedation is a response of alpha-2 stimulation. Thats why alpha 2 agonist dexmedetomidine and clonidine can be used as preanesthetic medication for sedation.

Beta blockers on the other hand cause insomnia.

thank you sir