Doripen500 mg/vial

Doripen is a broad-spectrum carbapenem antibiotic. Its FDA-approved (established) indications are:

• Complicated intra-abdominal infections caused by susceptible bacteria.
• Complicated urinary tract infections (UTIs), including pyelonephritis, caused by susceptible bacteria.

Doripen is generally reserved for serious, hospital-treated infections, including those caused by multidrug-resistant organisms, and is typically used when other antibiotics are unsuitable or have failed.

Important safety note: Doripen is not approved for the treatment of ventilator-associated bacterial pneumonia, as clinical studies showed higher mortality with Doripen compared to a comparator carbapenem in that setting. Use for pneumonia is considered inappropriate off-label use and should be avoided.

Each vial contains Doripenem (as doripenem monohydrate) equivalent to 250 mg or 500 mg of doripenem, as a sterile powder for reconstitution into an intravenous infusion.

Doripen is a synthetic broad-spectrum carbapenem antibiotic administered by intravenous infusion for the treatment of serious bacterial infections. As a member of the carbapenem class of beta-lactam antibiotics, it has activity against a wide range of gram-positive and gram-negative aerobic and anaerobic bacteria, including many strains resistant to other antibiotic classes. Because of its broad spectrum, Doripen is generally reserved for moderate to severe infections in hospitalized patients and is used under close medical supervision.

Doripen belongs to the carbapenem class of beta-lactam antibiotics, related to but distinct from penicillins and cephalosporins.

Doripenem exerts its bactericidal effect by binding to and inhibiting essential penicillin-binding proteins (PBPs) involved in bacterial cell wall synthesis. This inhibition disrupts cell wall assembly, leading to bacterial cell lysis and death. Doripenem is stable against many bacterial beta-lactamases, which broadens its spectrum of activity compared to some other beta-lactam antibiotics, though it can still be degraded by certain carbapenemases.

Following intravenous infusion, Doripenem shows linear pharmacokinetics, low plasma protein binding (approximately 8-9%), and distributes into extracellular fluid and various tissues. It has an elimination half-life of approximately 1 hour in patients with normal renal function and is primarily eliminated unchanged by the kidneys, requiring dose adjustment in renal impairment.

Doripen is reconstituted and further diluted, then administered as an intravenous infusion over 1 hour. It must be given by trained healthcare personnel and should not be administered by intramuscular, subcutaneous, or bolus IV injection. Infusion bags should be inspected for particulate matter and discoloration before use.

Valproic acid / divalproex sodium: Doripen, like other carbapenems, can significantly reduce serum valproic acid concentrations, sometimes below the therapeutic range, which may result in breakthrough seizures. Concurrent use is generally avoided; if Doripen must be used, alternative or supplemental anticonvulsant therapy should be considered and valproic acid levels monitored closely.

Probenecid: Probenecid competes with Doripen for renal tubular secretion, reducing its renal clearance and increasing plasma concentrations of Doripen. Coadministration with probenecid is not recommended.

Other beta-lactam antibiotics or live bacterial vaccines: Concurrent use of unrelated antibacterials should be guided by susceptibility results; discuss all current medications with your physician before starting Doripen.

Common side effects (occurring in approximately 5% or more of patients) include:

• Headache
• Nausea and diarrhea
• Rash
• Phlebitis (vein inflammation at the infusion site)

Less common but serious adverse effects that require prompt medical attention include:

• Severe allergic reactions (anaphylaxis), including swelling of the face/throat, difficulty breathing, or severe skin reactions such as Stevens-Johnson syndrome.
• Clostridioides difficile-associated diarrhea, which can range from mild to life-threatening colitis, and may occur up to several weeks after treatment ends.
• Seizures (see Precautions and Warnings).
• Blood disorders such as low white blood cell counts (leukopenia/neutropenia).
• Liver enzyme elevations.

Pregnancy: Animal reproduction studies with Doripen have not shown evidence of harm to the fetus at doses higher than typical human exposure, but adequate and well-controlled studies in pregnant women are lacking. Doripen should be used during pregnancy only if clearly needed and if the potential benefit justifies the potential risk to the fetus; consult a physician before use.

Lactation: It is not known whether Doripen is excreted in human breast milk. Caution should be exercised when Doripen is administered to a breastfeeding woman, and a physician should weigh the benefits of treatment against any potential risk to the infant.

Hypersensitivity reactions: Serious and occasionally fatal hypersensitivity reactions have been reported with beta-lactam antibiotics. Before starting Doripen, inform your physician of any history of allergic reactions to penicillins, cephalosporins, other carbapenems, or other allergens, since partial cross-reactivity is possible.

Seizure risk: Carbapenems, including Doripen, may lower the seizure threshold. The risk is higher in patients with a history of seizure disorders, central nervous system abnormalities, or renal impairment (where doses have not been appropriately adjusted). Use with caution in these patients.

Drug interaction with valproic acid: Concurrent use of Doripen with valproic acid or divalproex sodium is generally avoided due to the risk of reduced valproic acid levels and breakthrough seizures (see Interactions).

Clostridioides difficile-associated diarrhea has been reported with nearly all antibacterial agents, including Doripen, and may range in severity from mild diarrhea to fatal colitis.

Not for pneumonia: Doripen should not be used to treat ventilator-associated bacterial pneumonia due to an observed increase in mortality in clinical trials.

Development of drug-resistant bacteria: Use of Doripen in the absence of a proven or strongly suspected bacterial infection is unlikely to provide benefit and increases the risk of development of drug-resistant bacteria.

Antibiotic stewardship: Take Doripen exactly as prescribed by your physician; do not stop, extend, skip doses, or share this medicine with others without medical advice.

There is limited clinical experience with Doripen overdose. Symptoms, if they occur, would be expected to reflect an extension of known adverse effects, such as seizures or gastrointestinal upset. If an overdose of Doripen is suspected, seek immediate medical attention or contact emergency services/poison control. Treatment is supportive; Doripen can be removed by hemodialysis, which may be useful in cases of significant overdose in patients with renal impairment.

Store unopened vials of Doripen at room temperature (below 30°C), away from light and moisture. Once reconstituted and diluted, follow the healthcare facility's protocol for storage time and temperature prior to administration. Keep out of reach of children.

Renal impairment: Dose adjustment of Doripen is required based on creatinine clearance (see Dosage and Administration table). Data in patients on hemodialysis are insufficient.

Hepatic impairment: No dose adjustment of Doripen is considered necessary based on available pharmacokinetic data, as the drug is primarily renally eliminated.

Elderly patients: No dose adjustment is needed based on age alone; however, elderly patients more often have reduced renal function, so renal function should be assessed and dosing adjusted accordingly.

Pediatric patients: The safety and effectiveness of Doripen in pediatric patients (under 18 years) have not been established.

Duration of Doripen therapy depends on the infection being treated: typically 5 to 14 days for complicated intra-abdominal infections and 10 days (up to 14 days with bloodstream infection) for complicated urinary tract infections/pyelonephritis. In some cases, after at least 3 days of intravenous Doripen with clinical improvement, a physician may switch treatment to an appropriate oral antibiotic to complete the course. Always complete the full duration prescribed by your physician.

Doripen for injection is supplied as a sterile powder that must be reconstituted with an appropriate diluent (such as 0.9% Sodium Chloride Injection or 5% Dextrose Injection) by a trained healthcare professional, then further diluted in an infusion bag before intravenous administration. Reconstitution and dilution must follow the manufacturer's instructions and be performed using aseptic technique; the prepared solution should be used within the specified time and storage conditions.

Carbapenem antibiotic; a subclass of beta-lactam antibacterial agents.

Doripenem inhibits bacterial cell wall synthesis by binding to penicillin-binding proteins (PBPs), leading to cell wall breakdown, cell lysis, and bacterial death (bactericidal action).

Category B (legacy FDA classification)

The safety and effectiveness of Doripen have not been established in pediatric patients under 18 years of age. Doripen is not recommended for use in children and adolescents outside of specialist guidance, as adequate pediatric dosing and safety data are lacking.