Pharmacology of Substance Use Flashcards

A client reports using kratom daily to manage opioid cravings without a prescription. The counselor should know that kratom's active alkaloids (mitragynine, 7-HMG) primarily act on:

Answer: Mu and delta opioid receptors

Kratom alkaloids are partial mu-opioid agonists and have opioid-like analgesic and euphoric effects, carrying dependence and withdrawal risks similar to traditional opioids.

The 'kindling' phenomenon in repeated alcohol withdrawal refers to:

Answer: Each successive withdrawal episode becoming progressively more severe and seizure-prone

Neural sensitization from repeated alcohol withdrawal cycles lowers the seizure threshold with each episode, making clinical management of later withdrawals more medically urgent.

Which pharmacological feature of fentanyl makes it especially dangerous in the illicit drug supply?

Answer: Its extreme potency (50–100x morphine) meaning a lethal dose fits in a microscopic amount

Fentanyl's potency means a dose measured in micrograms can be lethal; small measurement errors or uneven mixing ('hot spots') in counterfeit pills or heroin cause overdoses even in experienced users.

Varenicline (Chantix) reduces tobacco cravings primarily by:

Answer: Acting as a partial agonist at alpha-4 beta-2 nicotinic acetylcholine receptors

As a partial agonist, varenicline provides enough receptor stimulation to reduce cravings and withdrawal while blocking full nicotine binding and blunting the reinforcement from smoking.

Protracted abstinence syndrome following cessation of heavy alcohol use is best characterized by:

Answer: Persistent anxiety, dysphoria, insomnia, and craving lasting months after acute withdrawal resolves

Neuroadaptive changes from chronic alcohol use take months to normalize; the resulting subclinical dysregulation of GABA, glutamate, and dopamine systems sustains craving and relapse vulnerability.

A client in opioid withdrawal is given clonidine. Its mechanism of action in this context is:

Answer: Alpha-2 adrenergic agonism that reduces noradrenergic hyperactivity from the locus coeruleus

During opioid withdrawal, the locus coeruleus becomes hyperactive; clonidine stimulates presynaptic alpha-2 receptors there, suppressing norepinephrine release and relieving sympathetic symptoms (sweating, anxiety, GI distress).

Which route of drug administration produces the fastest onset of action and the highest peak plasma concentration?

Answer: Intravenous

Intravenous injection delivers 100% of the dose directly into systemic circulation with no absorption barrier, producing peak brain concentrations within seconds and maximizing reinforcing potential.