Suspected cholinergic toxicity due to cevimeline hydrochloride and Bacopa monnieri interaction: a case report

BACKGROUND: Muscarinic agonists are indicated for the treatment of many conditions including ileus, urinary retention, glaucoma, and Sjögren’s syndrome. Due to their lack of tissue specificity, these drugs can lead to undesirable side effects at off-target sites and may be potentiated by supplements that impact the half-life of these drugs. CASE PRESENTATION: A 58-year-old Caucasian female with history of Sjögren’s syndrome, who was being managed with cevimeline, presented to the primary care office with reported hyperhidrosis, malaise, nausea, and tachycardia. She reported taking an herbal supplement containing B. monnieri and phosphatidylserine the previous night. It has been previously demonstrated that B. monnieri alters cytochrome P450 enzymes. Electrocardiogram showed no acute ST–T changes. Clinical improvement occurred with hydration and discontinuation of the supplement. CONCLUSIONS: To our knowledge, there has only been one other documented cevimeline overdose, and it was not associated with an herbal supplementation interaction. Physicians should actively elicit herbal supplement information from patients to anticipate possible drug–herb interactions. An additional consideration of clinical relevance is the known genetic variability that may affect drug responsiveness due to differences in metabolism and half-life of drugs that arise from common genetic variants of cytochrome P450 genes.