Can Dicyclomine Cause Altered Mental Status?
Yes, dicyclomine can definitively cause altered mental status through its anticholinergic effects on the central nervous system, including confusion, disorientation, delirium, hallucinations, and psychosis, particularly in elderly patients and those with cognitive impairment. 1
Mechanism and Clinical Manifestations
Dicyclomine is an anticholinergic medication that inhibits muscarinic receptors throughout the autonomic nervous system. 1 The FDA label explicitly warns that central nervous system effects include:
- Confusional state, disorientation, and amnesia 1
- Hallucinations, delirium, and psychosis (especially in sensitive individuals such as elderly patients and those with mental illness) 1
- Dysarthria, ataxia, coma, euphoria, fatigue, agitation, and inappropriate affect 1
- Drowsiness, dizziness, and blurred vision 1
These CNS symptoms typically resolve within 12 to 24 hours after discontinuation of the drug. 1
High-Risk Populations
Elderly patients are particularly vulnerable to dicyclomine-induced altered mental status. 1 The Mayo Clinic guidelines specifically identify strongly anticholinergic medications (including dicyclomine as a muscle relaxant with anticholinergic properties) as high-risk drugs that should be deprescribed in older adults. 2
Key risk factors include:
- Advanced age - The FDA label mandates caution in elderly patients who may be more susceptible to adverse effects 1
- Pre-existing cognitive impairment or dementia - Anticholinergic burden adversely affects cognition and functional status 2
- Multiple anticholinergic medications - The cumulative "anticholinergic burden" from multiple drugs significantly worsens cognitive outcomes 2
- Autonomic neuropathy - Requires cautious use due to enhanced sensitivity 1
Clinical Evidence
A case report documented a 61-year-old woman who presented with altered mental status (Glasgow Coma Scale 8/15) after exposure to dicyclomine and diphenhydramine, with physical findings consistent with anticholinergic toxicity including mydriasis, obtundation, and warm flushed skin. 3 This demonstrates dicyclomine's real-world capacity to cause severe altered mental status requiring intensive care.
Research confirms that anticholinergics like dicyclomine are among the worst offenders for drug-induced cognitive impairment, alongside benzodiazepines, opioids, and tricyclic antidepressants. 4, 5 Studies show that 22% of elderly patients with cognitive complaints were taking contraindicated medications that could affect cognition, with anticholinergics being frequently prescribed despite known risks. 6
Clinical Implications and Management
The liabilities associated with anticholinergic medications include injurious falls, episodes of confusion or delirium, emergency department visits, and hospitalizations. 2 The Drug Burden Index demonstrates that drugs with strong anticholinergic properties are associated with decline in cognition, functional status, and activities of daily living scores in older patients. 2
When evaluating altered mental status in any patient:
- Consider dicyclomine as a potential causative agent, especially in elderly patients or those with baseline cognitive impairment 1, 7
- Review all medications for anticholinergic burden - Multiple anticholinergic drugs have synergistic negative effects 2
- Discontinue dicyclomine if it is contributing to altered mental status - Symptoms typically resolve within 12-24 hours 1
- Avoid prescribing dicyclomine in patients with pre-existing cognitive impairment when alternative treatments are available 2, 6
Important Caveats
The FDA label warns that psychosis and delirium have been reported in sensitive individuals given anticholinergic drugs, and these effects are dose-related and usually reversible when treatment is discontinued. 1 However, in the presence of high environmental temperature, heat prostration can occur due to decreased sweating, potentially complicating the clinical picture. 1
Dicyclomine should not be used in patients with myasthenia gravis (except to reduce adverse muscarinic effects of anticholinesterase), and caution is required in patients with hepatic and renal impairment where drug accumulation may worsen CNS effects. 1