Meperidine is a widely prescribed opioid analgesic used in a variety of clinical situations.
The parent compound has central nervous system depressant effects. However, the sole active metabolite, normeperidine, is a central nervous system excitatory agent and has the ability to cause seizures, especially in patients with renal failure. Reported here is the case of a man with normal renal function who had a tonic-clonic seizure due to meperidine that was administered for the pain of underlying chronic pancreatitis. It is little appreciated, however, that patients with normal renal function may be at risk for seizure activity in the setting of repeated high doses or when the drug is given with phenothiazines, which may increase blood levels of normeperidine.3 Clinicians should be aware of potential CNS toxicity when administering meperidine to patients with normal renal function, especially if the drug is administered concomitantly with a phenothiazine. This case report describes a patient with chronic pancreatitis and normal renal function, who had a generalized seizure after several doses of meperidine were given every 2 hours for an acute flare of abdominal pain and who was found to have elevated normeperidine levels.