Can Invanz (Ertapenem) cause seizures?

Ertapenem (Invanz) Can Cause Seizures

Yes, ertapenem (Invanz) can cause seizures as stated in the FDA drug label, with seizures occurring in 0.5% of patients during clinical trials. 1 This is a recognized adverse effect that requires clinical attention, particularly in certain high-risk populations.

Risk Factors for Ertapenem-Associated Seizures

The risk of seizures with ertapenem is higher in patients with:

• Pre-existing CNS disorders (brain lesions or history of seizures)
• Compromised renal function
• Advanced age
• Concomitant use of medications that may lower seizure threshold

Evidence from FDA Drug Label

The FDA drug label for ertapenem specifically warns:

• "Seizures and other central nervous system (CNS) adverse experiences have been reported during treatment with ertapenem" 1
• "During clinical investigations in adult patients treated with ertapenem (1 g once a day), seizures, irrespective of drug relationship, occurred in 0.5% of patients" 1
• "These experiences have occurred most commonly in patients with CNS disorders (e.g., brain lesions or history of seizures) and/or compromised renal function" 1

Case Reports Supporting the Association

Several case reports document ertapenem-associated seizures:

• A patient with no prior CNS disorder developed seizures after 3 days of ertapenem therapy despite appropriate dosing for renal function 2
• A peritoneal dialysis patient experienced 5 refractory seizures after just 2 doses of ertapenem 3
• A retrospective study found that 10% of hemodialysis patients receiving ertapenem developed neurotoxicity 4

Other Neurological Adverse Effects

Beyond seizures, ertapenem can cause other neurological adverse effects:

• Encephalopathy with delirium, agitation, and visual hallucinations 5
• Stroke-like symptoms including garbled speech 6
• Profound changes in mental status that may mimic other conditions, particularly in elderly patients 6

Management Recommendations

If ertapenem is necessary for a patient with risk factors for seizures:

1. Consider dose adjustment in patients with renal impairment
2. Monitor patients closely for neurological symptoms, especially during the first week of therapy
3. Consider anticonvulsant therapy for patients with known seizure disorders
4. Discontinue ertapenem if focal tremors, myoclonus, or seizures occur
5. Re-evaluate the dosage to determine whether it should be decreased or discontinued

Special Consideration: Interaction with Valproic Acid

The FDA label specifically warns about an important interaction:

• "Co-administration of carbapenems, including ertapenem, to patients receiving valproic acid or divalproex sodium results in a reduction in valproic acid concentrations" 1
• "The valproic acid concentrations may drop below the therapeutic range as a result of this interaction, therefore increasing the risk of breakthrough seizures" 1
• "The concomitant use of ertapenem and valproic acid/divalproex sodium is generally not recommended" 1

Conclusion

Ertapenem can cause seizures and other neurological adverse effects, particularly in high-risk patients. Healthcare providers should be vigilant about this potential adverse effect, adjust dosing appropriately in patients with renal impairment, and consider alternative antibiotics in patients with pre-existing seizure disorders or those on valproic acid therapy.