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Amitriptyline Anticholinergic Toxicity CKD — ESENeph MCQ

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ModerateDiabetic Kidney DiseaseAmitriptyline Anticholinergic Toxicity CKDESENeph

A 60-year-old man with type 2 diabetes and CKD G3b develops painful diabetic neuropathy. He is prescribed Amitriptyline 25 mg at night. After 2 weeks he develops urinary retention, constipation, dry mouth, and confusion. What has occurred?

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Correct answer: A — Amitriptyline has strong anticholinergic effects that are exacerbated in CKD (reduced clearance of active metabolites); older adults with CKD are particularly susceptible to anticholinergic toxicity – Amitriptyline should be avoided; Duloxetine or Gabapentin/Pregabalin (renally adjusted) are safer alternatives

Tricyclic antidepressants (Amitriptyline, Nortriptyline) have strong anticholinergic properties causing urinary retention, constipation, dry mouth, confusion, and cardiac conduction abnormalities. Active metabolites accumulate in CKD, amplifying toxicity. The Beers Criteria and STOPP/START criteria identify TCAs as potentially inappropriate in older adults with CKD. Safer alternatives for neuropathic pain in CKD include: Gabapentin/Pregabalin (renally dose-adjusted), Duloxetine (hepatically cleared, but avoid in severe CKD), topical Capsaicin, and Buprenorphine patches. NICE CG173 recommends against Amitriptyline in patients with significant anticholinergic burden.

Reference: NICE CG173 – Neuropathic Pain; BNF – Amitriptyline; Beers Criteria 2023