This invention relates to an oral or enteral pharmaceutical preparation comprising at least one synthetically cyclised alpha-conotoxin peptide having an amide cyclised backbone such that the peptide has no free N- or C-terminus, said peptide having the ability to inhibit a nicotinic acetylcholine receptor and comprising four cysteine residues bonded in pairs to form two disulfide bonds, wherein the N-terminus of the corresponding linear/non-cyclised conotoxin peptide is linked to the C-terminus by a peptide linker, in a vehicle which is pharmaceutically suitable for oral or enteral administration.