New and potent medications such as alpha 2-adrenergic agonists, topically active carbonic anhydrase inhibitors, and prostaglandin analogs, are now available for use in the treatment of glaucoma. These ophthalmic medications have the potential to cause serious drug interactions and systemic side effects. The primary care physician should be able to recognize and to monitor any potential adverse effects and interact with the prescribing ophthalmologist for optimal patient care.