Delavirdine + Warfarin = Precautionary

Effect on Concentration

Delavirdine
No change
Applies within class?
No
Warfarin
Unknown
Applies within class?
No

Pharmacologic Effects

Delavirdine
Effect
N/A
Applies within class?
No
Warfarin
Effect
N/A
Applies within class?
No

Interaction History

N/A

Last Updated 30-Jul-2018

Summary

Possible increases or decreases are seen with other NNRTI's. Use cautiously.

Sources

Delavirdine vs Warfarin ^

Study Design

Data about the interaction between warfarin and efavirenz is based on knowledge of the metabolic pathways of these agents, and occasional case studies. A case has been described of a patient on warfarin and efavirenz. The patient was on ddI, 3TC and efavirenz and received warfarin for a DVT.

Study Results

There was an apparent increase in warfarin activity such that the initial daily dose of 5 mg was reduced to 1.25 mg to normalise platelet count and INR. The authors explain the findings on the basis of an interaction (inhibition of CYP2C9) between warfarin and efavirenz.

Study Conclusions

The plasma concentration of Warfarin may potentially be increased or decreased with co-administration of EFV or NVP. It is recommended to monitor the anticoagulation levels with co-administration of Warfarin with the NNRTI’s.

References

Bonora S, Lanzafame M, D'avolio A, Trentini L, Lattuada E, Concia E, DiPerri G. Drug interactions between warfarin and efavirenz or lopinavir‐ritonavir in clinical treatment. Clinical Infectious Diseases. 2008; 1: 146-147.