Textbook Chpt. 11 Opioids

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Questions and Answers

What is the primary effect of prolonged heroin administration on mood states in experienced users?

Rapidly increasing euphoria with each injection

Sustained positive feelings throughout usage

Consistent feelings of sedation without mood change

A shift to unpleasant mood states after initial relief (correct)

Which demographic was more likely to report positive feelings after morphine administration in a classic study?

Former heroin addicts (correct)

Patients in severe pain

Current heroin users only

Individuals with no prior opioid use

What is the duration of the relief from unpleasant feelings after heroin injection?

Up to several hours

30-60 minutes (correct)

15-30 minutes

2-4 hours

Which condition describes the change in physical activity during the later stages of heroin use?

Decreased physical activity and increased isolation Signup and view all the answers

What factor contributes to individual variability in response to initial opioid use according to the studies referenced?

Previous experience with the drug Signup and view all the answers

Which of the following effects are known to develop tolerance with prolonged opioid use?

Respiratory depression Signup and view all the answers

What pharmacological mechanism primarily accounts for the analgesic effects of opioids?

Inhibition of nociceptor excitability Signup and view all the answers

How do opioids impact the gastrointestinal system as a side effect?

Decrease gastrointestinal motility Signup and view all the answers

Which opioid receptor type is NOT commonly associated with pain inhibition?

Sigma receptors Signup and view all the answers

In relation to opioid abuse, which statement accurately reflects the current prescribing trends?

A significant amount of opioids prescribed worldwide are in the United States. Signup and view all the answers

Which side effect of opioids is associated with the activation of opioid receptors in the central nervous system but does NOT typically develop tolerance?

Nausea and vomiting Signup and view all the answers

What is a common characteristic of opioids that contributes to their addictive potential?

Rapid development of physical dependence Signup and view all the answers

What is the main reason for the rise in opioid prescribing in the last decade regarding chronic pain?

Increased incidence of conditions that cause chronic pain Signup and view all the answers

What factor has a significant impact on the potential for abuse of oxycodone?

The drug's formulation and route of administration Signup and view all the answers

Which type of administration of oxycodone is associated with higher positive subjective ratings?

Intravenous administration Signup and view all the answers

What was the effect of increasing the infusion rate of oxycodone in studies with heroin-dependent participants?

Increased drug reinforcement and reward ratings Signup and view all the answers

Which duration of morphine administration was found to yield the greatest levels of reward?

2 minutes Signup and view all the answers

What consequence arises from rapid, high-dose delivery of opioids to the brain?

Higher potential for drug abuse Signup and view all the answers

What shared pattern is observed in studies of drug administration in both human and animal laboratories?

A peak followed by a steady amount of self-administered drug Signup and view all the answers

In relation to dose-dependent effects, how do higher doses of opioids compare to lower doses?

Higher doses result in higher positives in reward ratings. Signup and view all the answers

Why is there an emphasis on developing slow, extended-release formulations of opioids?

To prevent rapid, high-dose delivery and potential abuse Signup and view all the answers

What is a common effect observed with regard to the rate of drug infusion?

Faster infusion rates elevate positive subjective effects and drug high Signup and view all the answers

What subjective effects are commonly diminished when opioids are administered to individuals experiencing pain?

Euphoria and light-headedness Signup and view all the answers

Which receptor subtype is primarily involved in the unpleasant subjective effects reported at higher doses of pentazocine?

Partial agonist at к receptors Signup and view all the answers

How do the subjective effects of opioids differ between dependent users and non-dependent users?

Non-dependent users report more unpleasant effects. Signup and view all the answers

Which factor is NOT a reliable predictor of how much a participant will like an opioid drug?

Previous illicit drug use Signup and view all the answers

What unpleasant subjective effects can opioids that stimulate the к receptor induce?

Unpleasant bodily sensations and psychosis Signup and view all the answers

What is a common effect of opioids when administered parenterally or intravenously?

Heightened euphoria and reward Signup and view all the answers

Which of the following effects does NOT develop tolerance when opioids are used?

Analgesic effects Signup and view all the answers

What can be a consequence of high doses of pentazocine that involves cognitive abilities?

Difficulty concentrating Signup and view all the answers

Which opioid receptor is primarily responsible for the highest abuse liability?

μ receptors Signup and view all the answers

What does the pharmacological profile of an opioid drug include?

Potency and selectivity for receptors Signup and view all the answers

What is an expected effect of using opioids in high doses in non-dependent users?

Sedation and confusion Signup and view all the answers

What is the primary mechanism by which opioids can lead to respiratory depression?

By stimulating μ and δ receptors in respiratory-related neurons Signup and view all the answers

Which of the following effects does not develop a tolerance with repeated opioid use?

Pupil constriction Signup and view all the answers

What role do κ receptors play in the context of opioid use?

They inhibit dopamine release as a feedback mechanism. Signup and view all the answers

Which neurotransmitter's levels are suggested to be increased by drugs of abuse that target opioid receptors?

Dynorphin Signup and view all the answers

Which statement accurately describes the onset and duration of tolerance to opioids?

Tolerance can develop variably depending on the opioid's pharmacological mechanism. Signup and view all the answers

What component of the central nervous system is primarily responsible for nausea and vomiting induced by opioids?

The chemoreceptor trigger zone Signup and view all the answers

Which function is primarily suppressed by opioids due to their action on specific brainstem receptors?

Cough reflex Signup and view all the answers

Which opioid receptor type has its role in both reward and addiction open to debate?

δ receptors Signup and view all the answers

What happens to the respiratory centers in the brainstem when opioids are administered?

The centers are selectively inhibited leading to reduced breathing depth. Signup and view all the answers

Study Notes

Principal Effects of Opioids

Opioids have both analgesic and antitussive actions, along with side effects.
These side effects include nausea, vomiting, sedation, convulsions, itching, respiratory depression, endocrine-system suppression, reduced gastrointestinal motility, constipation, urinary retention, and pinpoint pupils.
Opioid prescribing has increased, leading to a rise in opioid abuse.
Approximately 80% of prescribed opioid drugs are dispensed in the United States.
Opioid abuse is a significant problem, with nearly two million Americans meeting diagnostic criteria for substance use disorder related to heroin or prescription pain relievers.
Abuse rates in primary care and pain clinics can reach 37%.

Analgesia

Opioids reduce nociceptor excitability.
Nociceptors are sensory neurons that transmit information about tissue injury.
Opioid drugs bind to receptors in pain-transmitting and pain-gating regions (m, d, and/or κ receptors).
This binding reduces action potentials, thereby lessening the pain signals.
Some opioids, such as morphine, oxycodone, and oxymorphone, block pain transmission within the thalamus.
Other opioid drugs can blunt pain signals transmitted through the spinal cord.

Reward

Opioid receptors are present in brain circuits associated with reward pathways.
These pathways include the mesocortical and mesolimbic dopamine pathways.
These pathways run from the ventral tegmental area (VTA) to the prefrontal cortex, ventral striatum (nucleus accumbens), and limbic system regions.
Opioid binding to μ receptors in the VTA and nucleus accumbens disinhibits dopamine neurons.
This heightened dopamine release leads to increased rewarding effects of opioids.
μ receptors are associated with the highest abuse liability.
к receptors can inhibit dopamine release, acting as a feedback mechanism.

Effects on Vital Life Functions

Opioid overdose frequently involves respiratory depression.
Opioids slow and reduce the depth of breathing by acting on µ and δ receptors in the pons and medulla oblongata.
Opioids also affect other vital functions, such as vomiting and coughing.

Effects of Opioids on Human Behavior

Nausea and vomiting are notable initial effects.
Opioids affect regions in the central and peripheral nervous systems, including the vagus nerve, gastrointestinal tract, vestibular system, cortex, and the chemoreceptor trigger zone (CTZ).
Blood-brain barrier is incomplete in CTZ making it prone to toxins, metabolites, and drugs.
Opioids stimulation of µ and δ receptors in CTZ triggers nausea and vomiting.
Miosis (pupil constriction) is a common side effect that is not significantly affected by repeated dosing.
Opioids tend to reduce heart rate but have other influencing impacts on cardiac function.
Opioids can lower blood pressure by dilating peripheral blood vessels causing flushing and sweating.
Opioids inhibit gastrointestinal motility and cause constipation.
Opioids can affect the endocrine system, including sex hormone levels.
Reduced sex drive is common in opioid users
Interference with the reproductive cycle can potentially result in infertility in both sexes.
Interference in the endocrine's stress response system can influence stress hormone levels

Impact on Pregnancy

Opioids can increase the demand for the drug and the chance of withdrawal.
Opioids can harm a fetus as they can decrease blood oxygen levels.
Addiction during pregnancy can have other impacts on the mother's health.
Babies born to addicted mothers often have low birth weights and may experience withdrawal symptoms.
Symptoms include irritability, respiratory distress, yawning, sneezing, tremors, difficulty in sucking, and swallowing.

Effects on Sleep

Opioids do not promote restful sleep.
Side effects include drowsiness, lethargy, nodding, and reduced sleep quality.
Opioid use can cause insomnia, sleep deprivation, elevated muscle tension in sleep, decreased deep (delta) and REM sleep.
Opioid use can also increase sleep apnea and oxygen desaturation.

Cognitive and Performance Effects

Opioid use can cause attention, concentration, and cognitive impairments.
This can impact memory, executive function, and perceptual abilities.
These effects are often difficult to separate from the pain condition itself.
Individuals may experience hallucinations, delirium, and coma in extreme cases.

Subjective Effects

Effects vary depending on individual experience, doses, and the person's condition.
Repeated opioid use can lead to reduced experience of euphoria, and more pronounced side effects.
Opioid use's impact on mood and emotional well-being is variable and frequently negative.
Studies utilizing laboratory settings have revealed different perspectives and results from those reported by anecdotal accounts from subjects in their natural environment

Human and Animal Laboratory Studies

Self-administration studies show opioids act as reinforcers.
Specific pharmacological drug profile indicators are not perfect predictors of drug use and abuse potential.
Additional indicators include the cost, the ease of access, and the routes of administration of a given opioid.
Both human and animal studies support the dose-dependent reinforcement effects of opioids.
Studies indicate that higher doses show increased rates of reinforcement.

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Description

Test your knowledge on the principal effects of opioids, including their analgesic and antitussive actions. This quiz also covers the side effects of opioids as well as the growing concern over opioid abuse in the United States. Challenge yourself and learn more about this important topic in medicine.