NNNNThe invention provides novel potent inhibitors of the ternary protein complex of nNOS PSD 95 and the NMDA receptor and pharmaceutical compositions comprising the inhibitors for prophylaxis and/or treatment of excitotoxic related disease and chronic pain conditions in a subject. The inhibitors are dimeric PSD 95 inhibitors comprising a first peptide or peptide analogue linked to a second peptide or peptide analogue by a linker wherein the first and the second peptide or peptide analogue comprise at least four amide bonded residues having a sequence YTXV or YSXV wherein a. Y is selected from among E Q and A or an analogue thereof and b. X is selected from among A Q D N Me A Me Q Me D and Me N or an analogue thereof and wherein a Cell Penetrating Peptide (CPP) is linked to the linker or to an amino acid side chain of the first and second peptide or peptide analogue. The linker can be a PEG or NPEG linker.
