Carnexiv Dosage

2.1 Dosage Information

CARNEXIV is a replacement therapy for oral carbamazepine. Carbamazepine treatment should generally be initiated with an oral carbamazepine formulation.

The total daily dose of CARNEXIV is 70% of the total daily oral carbamazepine dose from which patients are being switched (see Table 1). The total daily dose of CARNEXIV should be equally divided in four 30-minute infusions, separated by 6 hours.

Patients should be switched back to oral carbamazepine administration at their previous total daily oral dose and frequency of administration as soon as clinically appropriate. The use of CARNEXIV for periods of more than 7 days has not been studied.

Table 1. Determination of Total Daily Dose for CARNEXIV Infusion

2.2 Administration Information

CARNEXIV is for intravenous use only and must be diluted in a compatible diluent prior to infusion.

Using Table 2 as a guide, prepare the solution for each infusion by transferring the single dose volume of CARNEXIV to 100 mL of diluent solution (0.9% sodium chloride, lactated Ringer's solution, or 5% dextrose) and mixing gently.

Before administration, the prepared solution for infusion may be stored for a maximum of 4 hours at 20°C to 25°C (68°F to 77°F) or a maximum of 24 hours if refrigerated at 2°C to 8°C (36°F to 46°F).

Parenteral drug products should be inspected visually for particulate matter, cloudiness, or discoloration prior to administration, whenever solution and container permit. If any of these are present, discard the solution.

Administer each infusion intravenously over 30 minutes.

CARNEXIV injection vials are for single-dose only. Discard any unused portion.

Table 2. CARNEXIV Dose to Volume and Infusion Table

2.3 Renal Function Monitoring

Patients with renal impairment may be at greater risk for an adverse effect of CARNEXIV on renal function, and should have close monitoring of renal function during treatment with CARNEXIV. CARNEXIV should generally not be used in patients with moderate or severe renal impairment.

2.4 Serum Level Monitoring

Monitor serum carbamazepine concentrations in conditions in which alterations in carbamazepine metabolism can occur. This includes patients who have hepatic impairment and patients on drugs that either induce or inhibit carbamazepine metabolism.

2.5 Laboratory Testing Prior to Carbamazepine Initiation

Prior to initial treatment with carbamazepine, test patients with ancestry in genetically at-risk populations for the presence of the HLA-B*1502 allele. The high resolution genotype test is positive if one or two HLA-B*1502 alleles are present. Avoid use of CARNEXIV in patients testing positive for the allele, unless the benefit clearly outweighs the risk.

Complete pretreatment blood counts, including platelets and possibly reticulocytes and serum iron, should be obtained as a baseline. If a patient in the course of treatment exhibits low or decreased white blood cell or platelet counts, the patient should be monitored closely. Discontinuation of CARNEXIV should be considered if any evidence of significant bone marrow depression develops.

Baseline and periodic evaluations of liver function, particularly in patients with a history of liver disease, must be performed during treatment with carbamazepine because liver damage may occur. Discontinue CARNEXIV in cases of aggravated liver dysfunction or active liver disease.