ERTAPENEM Drug Interactions: What You Need to Know

INTERACTIONS

• Co-administration with probenecid inhibits the renal excretion of ertapenem and is therefore not recommended. ( 7.1 )
• The concomitant use of ertapenem and valproic acid/divalproex sodium is generally not recommended. Anti-bacterials other than carbapenems should be considered to treat infections in patients whose seizures are well controlled on valproic acid or divalproex sodium. ( 5.2 , 7.2 )

7.1 Probenecid Probenecid interferes with the active tubular secretion of ertapenem, resulting in increased plasma concentrations of ertapenem <span class="opacity-50 text-xs">[see Clinical Pharmacology (12.3) ]</span> . Co-administration of probenecid with ertapenem is not recommended.

7.2 Valproic Acid Case reports in the literature have shown that co-administration of carbapenems, including ertapenem, to patients receiving valproic acid or divalproex sodium results in a reduction of valproic acid concentrations. The valproic acid concentrations may drop below the therapeutic range as a result of this interaction, therefore increasing the risk of breakthrough seizures. Although the mechanism of this interaction is unknown, data from in vitro and animal studies suggest that carbapenems may inhibit the hydrolysis of valproic acid&apos;s glucuronide metabolite (VPA-g) back to valproic acid, thus decreasing the serum concentrations of valproic acid <span class="opacity-50 text-xs">[see Warnings and Precautions (5.3) ]</span> .

4 CONTRAINDICATIONS

• Ertapenem for Injection is contraindicated in patients with known hypersensitivity to any component of this product or to other drugs in the same class or in patients who have demonstrated anaphylactic reactions to beta-lactams.
• Due to the use of lidocaine HCl as a diluent, Ertapenem for Injection administered intramuscularly is contraindicated in patients with a known hypersensitivity to local anesthetics of the amide type.
• Known hypersensitivity to product components or anaphylactic reactions to β-lactams. ( 4 )
• Due to the use of lidocaine HCl as a diluent, Ertapenem for Injection administered intramuscularly is contraindicated in patients with a known hypersensitivity to local anesthetics of the amide type. ( 4 )

AND PRECAUTIONS

• Serious hypersensitivity (anaphylactic) reactions have been reported in patients receiving β-lactams. ( 5.1 )
• Seizures and other central nervous system adverse experiences have been reported during treatment. ( 5.2 )
• Co-administration of Ertapenem for Injection with valproic acid or divalproex sodium reduces the serum concentration of valproic acid potentially increasing the risk of breakthrough seizures. ( 5.3 )
• Clostridioides difficile -associated diarrhea (ranging from mild diarrhea to fatal colitis): Evaluate if diarrhea occurs. ( 5.4 )
• Caution should be taken when administering Ertapenem for Injection intramuscularly to avoid inadvertent injection into a blood vessel. ( 5.5 )

5.1 Hypersensitivity Reactions Serious and occasionally fatal hypersensitivity (anaphylactic) reactions have been reported in patients receiving therapy with beta-lactams. These reactions are more likely to occur in individuals with a history of sensitivity to multiple allergens. There have been reports of individuals with a history of penicillin hypersensitivity who have experienced severe hypersensitivity reactions when treated with another beta-lactam. Before initiating therapy with Ertapenem for Injection, careful inquiry should be made concerning previous hypersensitivity reactions to penicillins, cephalosporins, other beta-lactams and other allergens. If an allergic reaction to Ertapenem for Injection occurs, discontinue the drug immediately. Serious anaphylactic reactions require immediate emergency treatment as clinically indicated.

5.2 Seizure Potential Seizures and other central nervous system (CNS) adverse experiences have been reported during treatment with Ertapenem for Injection <span class="opacity-50 text-xs">[see Adverse Reactions (6.1) ]</span> . During clinical investigations in adult patients treated with Ertapenem for Injection (1 g once a day), seizures, irrespective of drug relationship, occurred in 0.5% of patients during study therapy plus 14-day follow-up period <span class="opacity-50 text-xs">[see Adverse Reactions (6.1) ]</span> . These experiences have occurred most commonly in patients with CNS disorders (e.g., brain lesions or history of seizures) and/or compromised renal function. Close adherence to the recommended dosage regimen is urged, especially in patients with known factors that predispose to convulsive activity. Anticonvulsant therapy should be continued in patients with known seizure disorders. If focal tremors, myoclonus, or seizures occur, patients should be evaluated neurologically, placed on anticonvulsant therapy if not already instituted, and the dosage of Ertapenem for Injection re-examined to determine whether it should be decreased or discontinued.

5.3 Interaction with Valproic Acid Case reports in the literature have shown that co-administration of carbapenems, including ertapenem, to patients receiving valproic acid or divalproex sodium results in a reduction in valproic acid concentrations. The valproic acid concentrations may drop below the therapeutic range as a result of this interaction, therefore increasing the risk of breakthrough seizures. Increasing the dose of valproic acid or divalproex sodium may not be sufficient to overcome this interaction. The concomitant use of ertapenem and valproic acid/divalproex sodium is generally not recommended. Anti-bacterials other than carbapenems should be considered to treat infections in patients whose seizures are well controlled on valproic acid or divalproex sodium. If administration of Ertapenem for Injection is necessary, supplemental anti-convulsant therapy should be considered <span class="opacity-50 text-xs">[see Drug Interactions (7.2) ]</span> .

5.4 Clostridioides difficile -Associated Diarrhea (CDAD) CDAD has been reported with use of nearly all antibacterial agents, including ertapenem, and may range in severity from mild diarrhea to fatal colitis. Treatment with antibacterial agents alters the normal flora of the colon leading to overgrowth of Clostridioides difficile . Clostridioides difficile produces toxins A and B which contribute to the development of CDAD. Hypertoxin producing strains of Clostridioides difficile cause increased morbidity and mortality, as these infections can be refractory to antimicrobial therapy and may require colectomy. CDAD must be considered in all patients who present with diarrhea following antibiotic use. Careful medical history is necessary since CDAD has been reported to occur over two months after the administration of antibacterial agents. If CDAD is suspected or confirmed, ongoing antibiotic use not directed against Clostridioides difficile may need to be discontinued. Appropriate fluid and electrolyte management, protein supplementation, antibiotic treatment of Clostridioides difficile , and surgical evaluation should be instituted as clinically indicated.

5.5 Caution with Intramuscular Administration Caution should be taken when administering Ertapenem for Injection intramuscularly to avoid inadvertent injection into a blood vessel <span class="opacity-50 text-xs">[see Dosage and Administration (2.7) ]</span> .

5.6 Development of Drug-Resistant Bacteria As with other antibiotics, prolonged use of Ertapenem for Injection may result in overgrowth of non-susceptible organisms. Repeated evaluation of the patient&apos;s condition is essential. If superinfection occurs during therapy, appropriate measures should be taken.

Prescribing

Ertapenem for Injection in the absence of a proven or strongly suspected bacterial infection or a prophylactic indication is unlikely to provide benefit to the patient and increases the risk of the development of drug-resistant bacteria.

5.7 Laboratory Tests While Ertapenem for Injection possesses toxicity similar to the beta-lactam group of antibiotics, periodic assessment of organ system function, including renal, hepatic, and hematopoietic, is advisable during prolonged therapy.