INDICATIONS AND USAGE
CONTEPO (fosfomycin) is indicated for the treatment of patients 18 years and older with complicated urinary tract infections (cUTI),
including acute pyelonephritis, caused by susceptible isolates of Escherichia coli and Klebsiella pneumoniae.
Usage to Reduce Development of Drug-Resistant Bacteria
To reduce the development of drug-resistant bacteria and maintain the effectiveness of CONTEPO and other antibacterial drugs, CONTEPO should be used only to treat infections that are proven or strongly suspected to be caused by susceptible bacteria
IMPORTANT SAFETY INFORMATION
Contraindications
CONTEPO is contraindicated in patients with known serious hypersensitivity to fosfomycin, or any of the excipients.
Warning and Precautions
Serum Electrolyte Abnormalities: CONTEPO contains 1,980 mg of sodium in each vial. The high sodium load associated with the use of CONTEPO may result in changes in serum electrolytes, such as increased levels of serum sodium and decreased levels of potassium, calcium, and phosphorous. Electrolyte disturbances, such as hypokalemia and hypocalcemia, may potentiate cardiac effects, including QT prolongation. In a phase 2/3 comparator-controlled clinical trial in patients with cUTI, the following occurred more frequently in CONTEPO-treated patients compared with piperacillin/tazobactam-treated patients: hypokalemia (9.9%), hypernatremia (3.4%), hypophosphatemia (2.1%), and hypocalcemia (3.9%). Monitor serum electrolyte levels and fluid status during treatment with CONTEPO. Electrolyte supplementation may be necessary in some cases. Monitor for signs of edema, particularly in patients who should restrict their sodium intake or are prone to fluid overload.
QT Prolongation: CONTEPO has been shown to prolong the QT interval in some patients. QT prolongation can lead to development of torsade de pointes-type ventricular tachycardia with the risk increasing as the degree of prolongation increases. The risk of QT prolongation may increase in patients with electrolyte abnormalities, or those that have conditions or take medications that may cause an electrolyte imbalance. Avoid CONTEPO in patients with known QT prolongation or ventricular arrhythmias, including a history of torsade de pointes. Monitor electrolytes during treatment with CONTEPO.
Increase Transaminase Levels: In a phase 2/3 clinical trial, increases in transaminases occurred more frequently in CONTEPO-treated
patients compared to piperacillin/tazobactam-treated patients. Transaminases (alanine aminotransferase (ALT) or aspartate aminotransferase (AST))
were elevated ≥ 3x upper limit of normal (ULN) in 10.3% of patients receiving CONTEPO and 4.8% of patients receiving piperacillin/tazobactam.
Transaminase elevations were asymptomatic and reversible. Monitor hepatic enzymes during CONTEPO treatment.
Hypersensitivity Reactions: Hypersensitivity reactions, such as rash, urticaria, and anaphylaxis have been reported. Before initiating therapy with CONTEPO, it is important to inquire about previous hypersensitivity reactions to oral or parenteral fosfomycin. If an allergic reaction to CONTEPO occurs, discontinue the drug immediately.
Neutropenia Including Agranulocytosis: Neutropenia has been reported in patients receiving IV fosfomycin therapy. Monitor complete blood counts during CONTEPO therapy particularly in patients with pre-existing conditions or patients receiving concomitant drugs that may predispose to bone marrow suppression. Discontinue CONTEPO if neutropenia occurs and consider alternative therapies.
Clostridioides difficile-Associated Diarrhea: Clostridioides difficile-associated diarrhea (CDAD) has been reported with use of nearly all systemic antibacterial agents, including CONTEPO, and may range in severity from mild to fatal colitis. Careful medical history is necessary because CDAD has been reported to occur more than 2 months after administration of antibacterial agents. If CDAD is confirmed, discontinue antibacterials not directed against C. difficile, if possible.
Development of Drug-resistant Bacteria: Prescribing CONTEPO in the absence of a proven or strongly suspected bacterial infection indication is unlikely to provide benefit to the patient and increases the risk of the development of drug-resistant bacteria.
Adverse Reactions
The most common adverse reactions occurring in ≥ 2% of patients receiving CONTEPO were transaminase elevations (10.3%), hypokalemia (9.9%), neutropenia (6.4%), nausea (4.3%), diarrhea (3.9%), vomiting (3.9%), hypocalcemia (3.9%), hypernatremia (3.4%), headache (2.6%), and hypophosphatemia (2.1%).
Drug Interactions
Avoid co-administration of CONTEPO with drugs known to prolong the QT interval.
Use in Specific Populations
Lactation: Breastfeeding is not recommended during treatment and 24 hours after the last dose.
Geriatric Use: Because elderly patients are more likely to have decreased cardiac and renal function, care should be taken in dose selection, and electrolytes, fluid status, and renal function should be monitored. Dosage adjustment in elderly patients should take into account renal function.
Renal Impairment: Dosage adjustment is required for patients with estimated CLcr 50 mL/min or less. Monitor estimated CLcr at least daily and adjust the dosage of CONTEPO accordingly. In patients requiring hemodialysis, CONTEPO should be administered after hemodialysis on hemodialysis days.
Hepatic Impairment: Monitor patients with severe hepatic impairment closely for fluid overload and electrolyte abnormalities.
Please see accompanying full CONTEPO Prescribing Information here.
