You could use a "stronger" anionic detergent, such as SDS, combined with heat, or you could use a strong chaotrope such as 8M urea or 6M guanidine hydrochloride. These treatments will result in denatured protein. If you require that the protein retain its native state, try using zwitterionic detergents, such as CHAPS or Zwittergent 3-12 or 3-14. The concentration used should be above the critical micellar concentration.

Can I add those detergents to the regular RIPA buffer? Does it require additional centrifugations?

Some RIPA buffer recipes already contain SDS and deoxycholate detergents, both of which are anionic.