To Forestall Further Damage To My Optic Nerve (glaucoma) I

To forestall further damage to my optic nerve (glaucoma) I am now taking Azopt and Travatan. My Doctor stopped prescribing Dorzolamide HCI Timolol because I experienced asthma and fatigue. Now, just one day later I continue to experience the same symptoms. I hope it is just that it takes more time for the Timolol to get out of my system. Comments?