Anticholinergic syndrome following an unintentional overdose of scopolamine

Scopolamine hydrobromide (hyoscine) is an antimuscarinic drug which is primarily used in the prophylaxis and treatment of motion sickness and as a premedication to dry bronchial and salivary secretions. In acute overdosage, the main clinical problem is central nervous system (CNS) depression. In Australia, tablets containing scopolamine hydrobromide 0.3 mg are available over the counter in packs of ten. The recommended dose for adults is one to two tablets as a single dose, repeated four to six hours later, if required. The maximum dose stated on the pack is four tablets over a 24-hour period with a caution regarding drowsiness and blurred vision. We describe a patient who presented with symptoms of anticholinergic syndrome secondary to an unintentional overdose of scopolamine. Whilst at work, the patient noticed that he had forgotten his prescribed medication, domperidone, at home; a friend gave him some travel sickness medication which contained scopolamine for relief of nausea. On a previous occasion, he had experienced a similar, less severe reaction with another anticholinergic agent, loperamide. This report highlights the need to consider nonprescription products, ie, over the counter medications, herbal/nutritional supplements as causes of anticholinergic syndrome when a patient presents with symptoms suggestive of this diagnosis.