Discussion
This case exemplifies several issues that can arise when diagnosing toxic psychosis caused by orally administered hyoscine. Hyoscine is usually prescribed in adult patients for the treatment of abdominal pain associated with cramps induced by gastrointestinal (GI) spasms. It is an antimuscarinic medication that works similarly to atropine. It is made from a belladonna alkaloid (Atropa belladonna, commonly known as deadly nightshade). It antagonizes acetylcholine at muscarinic receptors at therapeutic doses, but it can also antagonize nicotinic receptors at high doses.7
Confusion, hallucination, fatigue, short-term memory loss, difficulty urinating, blurred vision, skin redness, and changes in heart rate are all common complications or side effects of hyoscine butylbromide.8 A person suffering from anticholinergic intoxication can be described as ”red as a beet, hot as a hare, dry as a bone, blind as a bat, mad as a hatter.”  This is a representation of a patient’s flushed skin, hyperthermia, dry mucous membranes, blurred vision, and confusion or delirium.9 Most cases of hyoscine intoxication can be treated by stopping the offending drug and providing supportive care to lower the patient’s fever, keep them cool, and keep them hydrated. Benzodiazepines can be used to reduce agitation and restlessness in patients. Patients who have toxic psychosis for up to 48 hours and are a danger to themselves and others may need to be admitted to the hospital for close monitoring and management.10 In our case, however, the patient recovered completely after the drug was stopped for 24 hours. Due to laboratory limitations, the serum level of hyoscine was not measured.
Poonai et al. randomly assigned children aged 8–17 years with nonspecific colicky abdomen pain who reported to the pediatric emergency department at London Health Sciences Centre in London, Ontario, to receive hyoscine butyl bromide, 10 mg orally, or acetaminophen, 15 mg/kg orally (maximum 975 mg). In this study, hyoscine butyl bromide did not outperform acetaminophen. 32/116 (27.6 percent) of individuals in the hyoscine butylbromide group experienced adverse reactions in the emergency department. Nausea, vomiting, dizziness, and photosensitivity were common adverse effects. There were no significant side effects.11
Anticholinergic-induced agitation, delirium, and hallucinations are treated with physostigmine, an acetylcholinesterase inhibitor.12,13 While the patient is being observed, a test dose of physostigmine, usually 0.5 or 1 mg, can be given intramuscularly, subcutaneously, or intravenously.14,15 Arrhythmias or hypotension caused by the physostigmine-induced cholinergic crisis should be monitored closely. Before prescribing physostigmine, it’s important to rule out any potential contraindications like renal hypertension, hyperthyroidism, diabetes, or coronary artery disease.