<p><strong>Metabolism and nutrition disorders</strong>: Common: decreased appetite<br />
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<strong>Psychiatric disorders</strong>: Common: irritability, aggression, restlessness, depression (pre-existing depression may be unmasked), drug tolerance (especially during prolonged use), agitation.<br />
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<strong>Nervous system disorders</strong>: Very common: somnolence, especially at the beginning of treatment and when higher doses are used; Common: sedation, dizziness, disturbance in attention, slow speech/dysarthria/ speech disorder (particularly with high doses or in long-term treatment, and are reversible), headache, tremor, ataxia.<br />
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<strong>Eye Disorders</strong>: Uncommon: diplopia (particularly with high doses or in long-term treatment and is reversible)<br />
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<strong>Respiratory, thoracic and mediastinal disorders</strong>: Not known: respiratory depression respiratory failure (particularly in patients with pre-existing compromised respiratory function e.g. in patients with bronchial asthma or brain damage)<br />
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<strong>Gastrointestinal disorders</strong>: Common: dry mouth, nausea, constipation<br />
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<strong>Skin and subcutaneous disorders</strong>: Uncommon: rash; Not known: photosensitivity reaction urticaria; Steven Johnson syndrome, toxic epidermal necrolysis (including some cases with fatal outcome);<br />
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<strong>Musculoskeleteal and connective tissue disorders</strong>: Not known: muscle spasms, muscle weakness<br />
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<strong>General disorders and administration site conditions</strong>: Very common: fatigue, especially at the beginning of treatment and when higher doses are used. Not known: slow response to stimuli, hypothermia<br />
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<strong>Investigations</strong>: Uncommon: weight increased (particularly with high doses or in long-term treatment).</p>