Pharmacology Lecture 10: Opioids

What is the FDA risk class for opioid analgesics?

Class II

What is the receptor that perceives pain?

Nociceptor

Where do the primary afferent neurons for nociceptors enter?

Dorsal horn of spinal cord

What area of the brain handles responses to autonomic events from nociceptors?

Brainstem

What area of the brain is the major relay station that sends information from nociceptors to the cortex?

Thalamus

What are the fibers that conduct impulses with intermediate velocity and respond to high intensity stimuli?

A Delta fibers

What are the fibers that conduct impulses slowly and produce action potentials in response to stimuli?

C fibers

Where do C-fibers synapse?

Spinal cord

Which receptor subtype has a higher affinity for endorphins?

Mu

Which receptor subtype has a higher affinity for enkephalins?

Delta

Which receptor subtype has a higher affinity for dynorphins?

Kappa

What type of opioids participate in the maintanence of body homeostasis?

Endogenous opioids

What is inhibited by endogenous opioids?

Hypothalamus

What levels are decreased by endogenous opioids?

Corticosteroid levels

What is the pre-synaptic effect of opioids?

Calcium influx reduction

What levels are decreased by calcium influx reduction by opioids?

Neurotransmitters

What is the post-synaptic effect of opioids?

Potassium efflux increase

What is the effect of potassium efflux increase by opioids?

Fiber hyperpolarization

What does morphine bind to for its mechanisms in the central nervous system?

Mu receptor

In which two areas does morphine have an effect on?

1. Central nervous system

2. Gastrointestinal tract

What are the two primary actions of morphine?

1. Sedation

2. Analgesia

What can opioids suppress in the medulla?

Coughs

What is the gastrointestinal effect of opioids?

Constipation

How do opioids affect the eyes?

Pupillary constriction

How can opioids aggravate asthma?

Bronchiolar constriction

What should be reduced before an operation for a patient that take opioids?

Anesthetic dose

What is the heart condition that could be caused by opioid use?

Myocardial infarction

What is the effect of using sedatives with opioids?

Increased CNS depression

What is the effect of using antipsychotics with opioids?

Increased sedation

What is the effect of using monoamine oxidase inhibitors with opioids?

Contraindication for opioids?

What percentage of patients experience at least one side effect from opioids?

50 - 80%