I begyndelsen af behandlingen kan nogle patienter føle svimmelhed eller svaghed (med langsom hjertefrekvens), særlig når man rejser sig fra liggende eller siddende stilling.
196  Muscle stiffness or spasm (including eye movements).  Problems with speech.  Unusual movement (especially of the face or tongue).  Constipation.  Dry mouth.  Rash.  Loss of strength.  Extreme tiredness.  Water retention leading to swelling of the hands, ankles or feet.  In the early stages of treatment, some people may feel dizzy or faint (with a slow heart rate), especially when getting up from a lying or sitting position.