Like all medicines, this medicine can cause side effects, although not everybody gets them.
Very common (may affect more than 1 in 10 people)
Confusion, dizziness, blurred vision, headache, rapid back-and-forth movement of the eyes, loss or impairment of memory (forgetfulness), vomiting, nausea, general weakness and drowsiness.
Common (may affect up to 1 in 10 people)
Decreased appetite, anxiety or worsened anxiety, hallucinations, inability to fall or stay asleep, agitation, disorientation, depression or worsened depression, nervousness, mood swings, mental status changes (thinking abnormal, confusion), paranoia, irritability, worsened confusion, difficulty with learning, memory or thinking, reflexes absent or impaired, problems expressing or understanding words, slurred speech, difficulty with speech or loss of ability to speak, sluggishness, balance or coordination impaired, burning sensation, increased abnormal sensation, reduced level of consciousness (unresponsive or almost unconscious), sedation, difficulty in concentrating, problems with the sense of smell, odd or no sense of taste, shaking, pins and needles, double vision, visual disturbance, intolerance to light, tinnitus (ringing in the ears), dizziness or spinning sensation, light-headedness or dizziness when standing, low blood pressure, shortness of breath, dry mouth, abdominal pain, worsened nausea, diarrhoea, constipation, sweating, itching, muscle weakness, muscle spasms, muscle cramp, muscle or joint pain, difficult or painful urination, difficulty starting or controlling urination, feeling jittery, falling, pain or pain exacerbated, fatigue, feeling cold, swelling of the face, legs or feet, chest pain, blood chemistry changes, mental impairment and weight decreased.
Uncommon (may affect up to 1 in 100 people)
Infection of the blood stream, delirium (feeling of mental confusion), psychotic disorder (abnormal thinking and perceptions), thought disorders, abnormal dreams, incoherence (inability to make sense), loss of consciousness, stupor (unresponsive/difficult to arouse), stroke, encephalopathy (brain disorder), aggressiveness, abnormal heart rhythm, difficulty breathing, indigestion, rash, muscle inflammation, back pain, muscle twitching, neck pain, acute kidney failure, abnormal heart trace measurements (ECG), raised body temperature, difficulty walking.