Pharmacology in Addictions Nursing Flashcards

A patient with severe alcohol use disorder is prescribed disulfiram. The nurse educates the patient that if they consume alcohol, they will experience a severe adverse reaction. This reaction is caused by the inhibition of which enzyme, leading to the accumulation of acetaldehyde?

Answer: Aldehyde dehydrogenase

Disulfiram works by irreversibly inhibiting aldehyde dehydrogenase, the enzyme responsible for metabolizing acetaldehyde into acetate. When alcohol is consumed, acetaldehyde builds up, causing the highly unpleasant symptoms of the disulfiram-ethanol reaction, such as flushing, nausea, and tachycardia.

A nurse is administering varenicline (Chantix) to a patient for smoking cessation. Which of the following best describes the dual mechanism of action for this medication?

Answer: It is a partial agonist at α4β2 nicotinic receptors, reducing cravings and withdrawal while also blocking nicotine from binding.

Varenicline is a partial agonist at the α4β2 nicotinic acetylcholine receptor. This action provides mild stimulation to reduce withdrawal symptoms and cravings. Simultaneously, it binds to these receptors with high affinity, which blocks nicotine from cigarettes from binding, thus reducing the rewarding and reinforcing effects of smoking.

A patient with opioid use disorder is being considered for Medication-Assisted Treatment (MAT). When comparing methadone and buprenorphine, what is a key pharmacological difference a CARN should understand?

Answer: Buprenorphine has a 'ceiling effect' on respiratory depression, making it safer in an overdose than methadone.

Buprenorphine is a partial mu-opioid agonist, meaning its effects plateau at higher doses. This 'ceiling effect' applies to respiratory depression, making it a safer option concerning overdose risk compared to methadone, which is a full opioid agonist and has no ceiling effect.

A patient who has maintained abstinence from alcohol for several months is prescribed acamprosate (Campral). The nurse should explain that the primary goal of this medication is to:

Answer: Restore the balance between GABA and glutamate neurotransmission to reduce cravings.

Acamprosate is thought to work by modulating and normalizing alcohol-disrupted brain activity, specifically by restoring the balance between the excitatory neurotransmitter glutamate and the inhibitory neurotransmitter GABA. This action helps to reduce the protracted withdrawal symptoms like craving and anxiety that can lead to relapse.

Which of the following is the primary mechanism by which naltrexone assists in the treatment of both alcohol and opioid use disorders?

Answer: It is an opioid receptor antagonist that blocks the euphoric and rewarding effects of opioids and alcohol.

Naltrexone is a pure opioid receptor antagonist. For opioid use disorder, it directly blocks the opioid receptors, preventing the euphoric effects of heroin or other opioids. For alcohol use disorder, it blocks the endogenous opioid system's response to alcohol, reducing the pleasurable feelings and reinforcement associated with drinking.

A patient is undergoing a medically supervised withdrawal from a long-term, high-dose benzodiazepine dependence. Which pharmacological principle is most critical for the nurse to consider when managing this process?

Answer: Gradually tapering the dose, potentially substituting with a long-acting benzodiazepine, to prevent severe withdrawal symptoms.

Abrupt cessation of benzodiazepines after prolonged use can lead to severe and life-threatening withdrawal symptoms, including seizures. The standard of care is a gradual dose reduction over an extended period. Often, a short-acting benzodiazepine is switched to a long-acting one (like diazepam) to provide more stable plasma levels and a smoother tapering process.