All prescribers should be aware of the range of possible adverse effects associated with antibiotics. Though perhaps less well recognized than other adverse effects, various neurotoxicities — including seizure, optic neuropathy, encephalopathy, peripheral neuropathy, and exacerbation of myasthenia gravis (MG) — may result from antibiotic use. This risk is increased in older patients, patients with impaired renal function, and patients with preexisting neurologic conditions.