Compounds of formula I or pharmaceutically acceptable salts thereof:
wherein R
1
, R
2
, R
3
, R
4
and Z are as defined in the specification as well as salts and pharmaceutical compositions including the compounds are prepared. They are useful in therapy, in particular in the management of pain.
化学式I的化合物或其药学上可接受的盐:其中R1、R2、R3、R4和Z的定义如说明书中所定义的那样,还制备了包括这些化合物的盐和药物组合物。它们在治疗中有用,特别是在疼痛管理方面。