The invention provides cyclic carboxamide compounds and analogues thereof of Formula I and the pharmaceutically salts and hydrates thereof. The variables R, R1, R6-R8, R16, R18, R19, M, n, T, Y, and Z are defined herein. Certain compounds of Formula I are useful as antiviral agents. Certain cyclic carboxamide compounds and cyclic carboxamide analogues disclosed herein are potent and/or selective inhibitors of viral replication, particularly Hepatitis C virus replication. The invention also provides pharmaceutical compositions containing one or more cyclic carboxamide compounds or cyclic carboxamide analogues and one or more pharmaceutically acceptable carriers. Such pharmaceutical compositions may contain a cyclic carboxamide compound or cyclic carboxamide analogue as the only active agent or may contain a combination of a cyclic carboxamide compound or cyclic carboxamide analogue and one or more other pharmaceutically active agents. The invention also provides methods for treating viral infections, including Hepatitis C infections.