Purpose: To develop a Physicians' Guide to assist clinicians in the co
ncomitant use of glaucoma and systemic medications. Methods: The recor
ds of 100 consecutive patients with chronic open-angle glaucoma were r
etrospectively studied to determine the most common systemic medicatio
ns that are prescribed in this population. The ten most common drug cl
asses were then used to construct a guide to potential interactions ai
d side effects when these medications are used concomitantly with glau
coma drugs. Results: Eighty-four patients were receiving 1 or more med
ications (a mean of 3.5) for a mean of 2.6 systemic conditions. System
ic antihypertensive agents was the most common class of drugs, being u
sed by 48 patients. Aspirin, the most common single systemic drug, was
being used by 25 patients. Conclusions: A high percentage of patients
with chronic open-angle glaucoma receive a wide variety of medication
s for coexisting systemic disorders. The concomitant use of glaucoma a
nd systemic medications creates the potential for drug interactions, a
s well as side effects for both groups of drugs, for which the Physici
ans' Guide may be beneficial.