A pharmaceutical composition comprising a compound of the formula or a pharmaceutically acceptable salt thereof, together with a pharmaceutically acceptable carrier, wherein R 1 is (pyrimidinyl)C 0 -C 4 alkyl, (C 3 -C 7 cycloalkyl)C 0 -C 4 alkyl, (pyrazolyl)C 0 -C 2 alkyl, (pyrrolyl)C 0 -C 2 alkyl, (imidazolyl)C 0 -C 2 alkyl, (thienyl)C 0 -C 2 alkyl, (oxazolyl)C 0 -C 2 alkyl, (thiazolyl)C 0 -C 2 alkyl, pyrolidinyl, naphthyl, quinolinyl, isoquinolinyl, tetrahydronaphthyl, tetrahydroquinolinyl, tetrahydroisoquinolinyl, tetrahydrofuranyl, morpholinyl, piperidinyl or thiomorpholinyl, each of which is unsubstituted or substituted with one or more substituents independently chosen from halogen, hydroxyl, cyano, nitro, amino, -CHO, -COOH, C 1 -C 6 alkyl, C 1 -C 6 alkoxy, C 2 -C 6 alkanoyl, mono- or di- C 1 -C 6 alkylamino, mono- or di-C 1 -C 6 alkylcarboxamide, C 1 -C 6 alkylester, C 1 -C 6 alkylthio, C 1 -C 6 alkylsulfonyl, C 1 -C 2 haloalkyl, and C 1 -C 2 haloalkoxy, and with 0 or 1 substituents chosen from Y-Z- where Z is a covalent bond, C 1 -C 4 alkylene, -S-, -O-, -NR-, -C -, -NHC -, or -C NH-, where R is hydrogen or C 1 -C 4 alkyl, and Y is phenyl or pyridyl, each of which is unsubstituted or substituted with 1 to 3 substituents independently chosen from halogen, hydroxyl, cyano, nitro, amino, C 1 -C 4 alkyl, and C 1 -C 4 alkoxy; R 2 is hydrogen or methyl; R 3 and R 6 are both hydrogen; and R 5 and R 7 are both methyl; or one of R 5 and R 7 is methyl and the other is phenyl; or one of R 5 and R 7 is methyl and the other is difluoromethyl; with the proviso that: R 1 is not unsubstituted cyclohexyl when R 5 and R 7 are both methyl or one of R 5 and R 7 is methyl and the other is phenyl; R 1 is not 1-(4-fluorobenzyl)-1H-pyrazol-4-yl when one of R 5 and R 7 is methyl and the other is phenyl. R 1 is (pyrimidinyl)C 0 -C 4 alkyl, (C 3 -C 7 cycloalkyl)C 0 -C 4 alkyl, (pyrazolyl)C 0 -C 2 alkyl, (pyrrolyl)C 0 -C 2 alkyl, (imidazolyl)C 0 -C 2 alkyl, (thienyl)C 0 -C 2 alkyl, (oxazolyl)C 0 -C 2 alkyl, (thiazolyl)C 0 -C 2 alkyl, pyrolidinyl, naphthyl, quinolinyl, isoquinolinyl, tetrahydronaphthyl, tetrahydroquinolinyl, tetrahydroisoquinolinyl, tetrahydrofuranyl, morpholinyl, piperidinyl or thiomorpholinyl, each of which is unsubstituted or substituted with one or more substituents independently chosen from halogen, hydroxyl, cyano, nitro, amino, -CHO, -COOH, C 1 -C 6 alkyl, C 1 -C 6 alkoxy, C 2 -C 6 alkanoyl, mono- or di- C 1 -C 6 alkylamino, mono- or di-C 1 -C 6 alkylcarboxamide, C 1 -C 6 alkylester, C 1 -C 6 alkylthio, C 1 -C 6 alkylsulfonyl, C 1 -C 2 haloalkyl, and C 1 -C 2 haloalkoxy, and with 0 or 1 substituents chosen from Y-Z- where Z is a covalent bond, C 1 -C 4 alkylene, -S-, -O-, -NR-, -C -, -NHC -, or -C NH-, where R is hydrogen or C 1 -C 4 alkyl, and Y is phenyl or pyridyl, each of which is unsubstituted or substituted with 1 to 3 substituents independently chosen from halogen, hydroxyl, cyano, nitro, amino, C 1 -C 4 alkyl, and C 1 -C 4 alkoxy; R 2 is hydrogen or methyl; R 3 and R 6 are both hydrogen; and R 5 and R 7 are both methyl; or one of R 5 and R 7 is methyl and the other is phenyl; or one of R 5 and R 7 is methyl and the other is difluoromethyl; with the proviso that: R 1 is not unsubstituted cyclohexyl when R 5 and R 7 are both methyl or one of R 5 and R 7 is methyl and the other is phenyl; R 1 is not 1-(4-fluorobenzyl)-1H-pyrazol-4-yl when one of R 5 and R 7 is methyl and the other is phenyl. R 1 is not unsubstituted cyclohexyl when R 5 and R 7 are both methyl or one of R 5 and R 7 is methyl and the other is phenyl; R 1 is not 1-(4-fluorobenzyl)-1H-pyrazol-4-yl when one of R 5 and R 7 is methyl and the other is phenyl.