Moxalactam myoclonus, seizures, and encephalopathy.

Severe myoclonus, generalized seizures, and marked stupor occurred in a 39-year-old woman with chronic renal insufficiency after one week of moxalactam 2 g iv q8h. Moxalactam serum levels far exceeded the recommended therapeutic range. The drug half-life was 17 hours (normal 1.9). Excessively high levels of moxalactam, which penetrates the blood-brain-barrier relatively easily, may provoke seizures and encephalopathy.