Sedation. Hypersensitivity reactions. Lassitude, dizziness, tinnitus, inability to concentrate, incoordination, irritability, insomnia and tremors. Nausea, vomiting, diarrhoea, colic, epigastric pain, anorexia, dryness of mouth and constipation. Urinary retention. Palpitations, headache. Blurred vision, increased intraocular pressure. Muscular weakness. Rarely, blood dyscrasias e.g. agranulocytosis, haemolytic anaemia.