amitriptyline will increase effects of letibotulinumtoxinA by pharmacodynamic synergism. Use Caution/observe. medication with anticholinergic outcomes may potentiate botulinum toxin outcomes, which may end in extreme neuromuscular weak spot and heighten systemic anticholinergic consequences. trifluoperazine improves levels of letibotulinumtoxinA b… Read More