Collision-induced dissociation of protonated cyproheptadine: Ion-neutral complex mediated electron transfer versus hydride transfer reaction

•The gas-phase fragmentation of protonated cyproheptadine, an antihistamine drug, was investigated by electrospray ionization tandem mass spectrometry.•Intriguing ion/molecule complex mediated hydride transfer and electron transfer reactions are employed to rationale the fragmentation mechanism.•Comprehensive experimental and theoretical evidences confirmed the proposed mechanism.