The present invention relates to Substituted Quinolizine Derivatives of Formula (I): and pharmaceutically acceptable salts or prodrug thereof, wherein X, Y, R1, R2, R3, R4, R5, R9 and R10 are as defined herein. The present invention also relates to compositions comprising at least one Substituted Quinolizine Derivative, and methods of using the Substituted Quinolizine Derivatives for treating or preventing HIV infection in a subject.