A NK1 antagonist having the formula (I), wherein Ar1 and Ar2 are optionally substituted phenyl or heteroaryl, X1 is an ether, thio or imino linkage, R4 and R5 are not both H or alkyl, and the remaining variables are as defined in the specification, useful for treating a number of disorders, including emesis, depression, anxiety and cough. Pharmaceutical compositions. Methods of treatment and combinations with other agents are also disclosed.