FDA recently approved changes to the SUSTIVA (efavirenz) product labeling to include a new Warnings and Precautions regarding QTc prolongation. The following main changes to the product labeling were made:
The following sub-section was added in the WARNINGS AND PRECAUTIONS section.
- 5.2 QTc Prolongation: QTc prolongation has been observed with the use of efavirenz [see Drug Interactions (7.3, 7.4) and Clinical Pharmacology (12.2)]. Consider alternatives to SUSTIVA when co-administered with a drug with a known risk of Torsade de Pointes or when administered to patients at higher risk of Torsade de Pointes.
The following new sub-section was added in the DRUG INTERACTIONS section.
- 7.3 QT Prolonging Drugs: There is limited information available on the potential for a pharmacodynamic interaction between SUSTIVA and drugs that prolong the QTc interval. QTc prolongation has been observed with the use of efavirenz [see Clinical Pharmacology (12.2)]. Consider alternatives to SUSTIVA when co-administered with a drug with a known risk of Torsade de Pointes.
Revisions were made in Table 5 and subsection 7.5 for Drugs Without Clinically Significant Interactions with SUSTIVA.
- Specifically the clinical comment for Anti-infective: Clarithromycin now states: Consider alternatives to macrolide antibiotics because of the risk of QT interval prolongation. Likewise for Antimalarials: Artemether/lumefantrine the clinical comment states: Consider alternatives to artemether/ lumefantrine because of the risk of QT interval prolongation.
The following new sub-section was added in the Clinical Pharmacology section.
- 12.2 Pharmacodynamics-Cardiac Electrophysiology: The effect of SUSTIVA on the QTc interval was evaluated in an open-label, positive and placebo controlled, fixed single sequence 3-period, 3-treatment crossover QT study in 58 healthy subjects enriched for CYP2B6 polymorphisms. The mean Cmax of efavirenz in subjects with CYP2B6 *6/*6 genotype following the administration of 600 mg daily dose for 14 days was 2.25-fold the mean Cmax observed in subjects with CYP2B6 *1/*1 genotype. A positive relationship between efavirenz concentration and QTc prolongation was observed. Based on the concentration-QTc relationship, the mean QTc prolongation and its upper bound 90% confidence interval are 8.7 ms and 11.3 ms in subjects with CYP2B6*6/*6 genotype following the administration of 600 mg daily dose for 14 days [see Warnings and Precautions (5.2)].
You can view the updated label at Drugs@fda or DailyMed