Psychiatric Drugs and Medications Q 33

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Which of the following assessments is most essential before beginning a drug regimen of an antimuscarinic agent?

  

     A. Date of birth

     B. Ethnic background

     C. History of diabetes

     D. Activity intolerance

    

    

Correct Answer: A. Date of birth

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Antimuscarinic agents are contraindicated in elderly patients. Elderly patients are at an increased risk of and are more vulnerable to adverse anticholinergic effects due to differences in metabolism, excretion of medications, and changes in the CNS. In the elderly, antimuscarinic medications may correlate with increased morbidity, for several reasons, including due to increased risk of falls. Scopolamine and antimuscarinic medications should be used very cautiously in elderly patients.

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Option B: Scopolamine non-selectively affects all five muscarinic receptor subtypes (M1 thru M5), and anticholinergic symptoms, or anticholinergic syndrome, are theoretically possible. Additionally, there are over 600 medicinal products with anticholinergic activity. The antimuscarinic effects of these products have the potential to exacerbate the adverse effects of scopolamine.

Option C: Mydriasis is a potential complication of scopolamine. Although reports exist of bilateral cases, the literature suggests that the majority of cases of mydriasis are unilateral and ipsilateral to the side of their scopolamine patch, caused by the patient self-contaminating by touching their patch and then touching their eyes.

Option D: The reversal of scopolamine toxicity is not a widely reported topic. However, based on the mechanism of toxicity, physostigmine can be used to reverse anticholinergic symptoms. There are reports of the use of physostigmine in cases of scopolamine toxicity. The patient then requires monitoring for a cholinergic crisis with atropine available at the bedside. Additionally, as with most poisonings, vital signs and ECG should be obtained and monitored.

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