The 45-year-old son of a client calls the PMHNP to ask her to write a letter declaring his mother incompetent, and therefore unable to make medical decisions for herself. What is the most appropriate response?

Choice A reason: Creutzfeldt-Jacob disease is a rare neurodegenerative disorder caused by prion proteins. It presents with rapidly progressive dementia, myoclonus, and motor dysfunction, but does not typically include the classic triad of Wernicke’s encephalopathy.

Choice B reason: Lewy body dementia is characterized by fluctuating cognition, visual hallucinations, and parkinsonian features. While it may include motor and cognitive symptoms, it does not typically present with the acute ocular and vestibular signs seen in Wernicke’s encephalopathy.

Choice C reason: Wernicke’s encephalopathy is a neurologic emergency caused by thiamine deficiency, often due to chronic alcohol abuse. The classic triad includes ophthalmoplegia (e.g., nystagmus), ataxia, and confusion. The patient’s history and symptoms strongly support this diagnosis.

Choice D reason: Delirium is an acute disturbance in attention and cognition, often reversible and multifactorial. While it may coexist with Wernicke’s encephalopathy, it does not explain the specific ocular and vestibular findings.

Choice A reason: Gabapentin is a central nervous system (CNS) depressant that, when combined with buprenorphine, can significantly increase the risk of sedation, respiratory depression, and cognitive impairment. The synergistic depressant effects on the CNS can lead to symptoms such as lethargy, confusion, and impaired judgment. Clinical studies and pharmacological data confirm that co-administration of gabapentin with opioids like buprenorphine should be approached with caution due to the heightened risk of overdose and serious adverse effects.

Choice B reason: Naltrexone is an opioid antagonist used to treat opioid and alcohol dependence. It blocks the effects of opioids and does not cause CNS depression. If administered to someone on buprenorphine, it may precipitate withdrawal but would not typically cause lethargy or confusion unless withdrawal symptoms were severe. However, the patient has been stable on buprenorphine, and naltrexone would more likely cause acute withdrawal rather than the described symptoms.

Choice C reason: Naloxone is also an opioid antagonist, primarily used in emergency settings to reverse opioid overdose. It is not typically prescribed for long-term use and would not be expected to cause lethargy or confusion unless it precipitated withdrawal. Like naltrexone, its role is more acute and would not align with the described gradual onset of symptoms.

Choice D reason: Carbamazepine is an anticonvulsant and mood stabilizer. While it has CNS effects, its interaction with buprenorphine is not as pronounced or dangerous as gabapentin. It may cause sedation or dizziness, but it is less likely to cause the level of CNS depression described unless combined with other sedatives. It is not the most likely contributor in this scenario.