Narcotic Analgesics Quiz

Questions and Answers

What is a crucial physiological effect of morphine that can lead to respiratory arrest in patients?

Increased depth of respiration

Decreased sensitivity of the respiratory center to CO2 (correct)

Decreased blood pressure

Increased sensitivity of the respiratory center

Which of the following effects is associated with morphine's action on smooth muscles in the gastrointestinal tract?

Decreases peristalsis in the large intestine (correct)

Increases motility in the large intestine

Stimulates intestinal secretions

Increases gastric emptying

In patients with severe head injury, what is the primary reason morphine is contraindicated?

Decreases heart rate significantly

Increases sympathetic nervous system activity

Causes miosis which complicates diagnosis

Leads to increased intracranial pressure due to CO2 retention (correct)

What effect does morphine have on the biliary system?

Spasm of the sphincter of Oddi increases intrabiliary pressure Signup and view all the answers

Which statement correctly describes the effect of morphine on the urinary system in patients with benign prostatic hyperplasia?

It causes spasm of the bladder sphincter, leading to urine retention Signup and view all the answers

Which opioid receptor family is associated with the highest analgesic effects and is primarily targeted by strong agonists like morphine?

Mu Signup and view all the answers

What differentiates partial agonists like pentazocine from full agonists such as morphine in terms of receptor activation?

Partial agonists activate the receptor but produce a weaker response compared to full agonists. Signup and view all the answers

Which of the following statements correctly describes the action of opioids on the central nervous system?

Opioids act as depressants, increasing the pain threshold and altering perception. Signup and view all the answers

Which of the following best describes the classification of codeine within the opioid classification system?

Moderate agonist Signup and view all the answers

Which endogenous opioid peptide is NOT included in the complex pain inhibition system described?

Serotonins Signup and view all the answers

Study Notes

General Pharmacology of Narcotic Analgesics

Analgesics relieve pain and are classified as narcotic (central action) or non-narcotic (peripheral action).
Narcotics induce sedation and drowsiness; morphine is the prototype derived from opium poppy.
Opioids are natural opioids, including morphine and codeine.
Opioid receptors include mu, kappa, delta, and sigma, influencing pain perception and drug binding specificity.
Opioid receptors are inhibitory G-protein coupled, leading to decreased cAMP levels and cellular hyperpolarization.

Pharmacology of Morphine

Acts as a central depressant, altering pain perception and inducing drowsiness.
Causes respiratory depression, especially risky in COPD and asthma patients.
Exhibits antitussive effects by inhibiting the cough center.
Notable for pinpoint pupils (miosis), which is a classic sign of overdose.
Can cause nausea and vomiting due to stimulation of the chemoreceptor trigger zone.

Distribution and Pharmacokinetics

Morphine undergoes first-pass metabolism; routes include intramuscular, intravenous, subcutaneous, buccal, and transdermal.
It crosses the placenta, potentially affecting fetal respiration.
Metabolized primarily in the liver; active metabolite is morphine-6-glucuronide, while morphine-3-glucuronide is inactive.
The half-life is approximately 2 hours, and effects last 4-6 hours.

Clinical Uses

Effective for severe pain relief (visceral and somatic), anxiety relief in critical conditions, and cough suppression (codeine preferred).
Used in premedication for surgery and to alleviate dyspnea in acute left ventricular failure.

Adverse Effects and Contraindications

Common side effects: respiratory depression, vomiting, hypotension, and urinary retention.
Contraindicated in head injuries, severe liver disease, diverticulitis, and during labor.

Opioid Dependence and Tolerance

Tolerance primarily develops to respiratory depression, analgesia, and euphoria, with less effect on miosis.
Treatment includes gradual withdrawal, substitution with methadone, or clonidine for withdrawal syndromes.

Opioids Poisoning

Symptoms include coma, slow shallow respiration, and pinpoint pupils.
Treated initially with respiratory support and administration of Naloxone, a pure opioid antagonist.

Pharmacology of Other Members

Pethidine (Meperidine): Used for severe pain, causes less constipation, not useful for cough suppression.
Methadone: Less sedating, long half-life, used in analgesia and opioid dependence treatment.
Diamorphine (Heroin): Highly addictive, most potent opioid.
Fentanyl: Used for general anesthesia, potent and fast-acting.
Codeine: Milder analgesic, effective for cough and mild pain, converted less than 10% to morphine in the body.
Dextropropoxyphene and Tramadol: Used for pain, less addictive potential compared to strong opioids.

Opioid Antagonists

Naloxone: Fast-acting opioid antagonist, used in overdose cases; reverses respiratory depression.
Naltrexone: Longer-acting antagonist, can be taken orally; used for dependence and to decrease alcohol craving.
Nalorphine: Functions as an antagonist and partial agonist, depending on the context of use.

Description

Test your knowledge on the pharmacology of narcotic analgesics, including topics such as morphine and opioids dependence. This quiz covers the general pharmacology, various members of opioids, and their antagonists. Prepare yourself for questions on opioid poisoning and more!