Opioid Drugs Flashcards
What is an opiate?
morphine-like (chemical)
What is an opioid?
morphine-like (pharmacological actions), also includes antagonist drugs
What is an endorphin?
endogenous opioid peptides (enkephalins, dynorphins, B-endorphins, endomorphins)
What is a narcotic?
narcosis, stupor, sleep inducing (legal term)
What is the principal therapeutic effects of opioids? (3)
(1) Analgesia
(2) Cough suppression
(3) Constipation
What is the definition of pain?
an unpleasant sensory and emotional experience associated with, or described in terms of, actual or potential tissue damage
T/F Opioids analgesic management occurs with loss of consciousness.
FALSE; without LOC
What are the 3 aspects of pain that opioids (analgesia) are effective with?
(1) Pain management
(2) Continuous dull pain better relieved than sharp intermittent pain (i.e. neuropathic pain)
(3) Pain as a sensation and pain in the context of suffering. Morphinized patients still feel the pain but it is not as discomforting
T/F Pain management with opioids is selectively decreased.
TRUE; there is no effect on other senses (i,e, touch, vibration, temperature)
What are additional CNS effects that opioids have on the body? Which one is the primary consequence of opioid overdose?
(1) Euphoria
(2) Sedation
(3) Respiratory Depression: primary consequence of opioid overdose; decreased responsiveness of brain-stem respiratory center to CO2
What are the contraindications of opioids?
- Contraindicated in head trauma (potentiates respiratory depression and CO2 retention leads to cerebral artery vasodilation and increase in intracranial pressure.
- use cautiously in patients with COPD and asthma
What are 6 other effects of opioids?
(1) Cough suppression- depresses cough reflex
(2) miosis
(3) emesis
(4) constipation
(5) biliary tract
(6) cardiovascular system
What dosage do you have to use for cough suppressive effects?
low dose; effect not blocked by opioid receptor antagonists
T/F There is tolerance to the miosis effect.
FALSE; always will have the pinpoint pupils. They may mas pupillary changes in head trauma
What patients are more susceptible to emesis? What type of effect is emesis with opioid use?
Ambulatory patients; primarily first dose effect
T/F There is some tolerance to constipation effects on opioids.
TRUE; intermediate tolerance
How do opioids produce constipation?
Acts on nerves (intrinsic nerve plexi) and not on smooth muscle or secretory cells, increased muscle tone in duodenum and antrum of the stomach and decreased peristaltic movement in jejunum and colon
What are the CV effects of opioids? (2)
- no major effects on HR and BP
- opioid agonists can stimulate the release of histamine and thereby cause hypotension
T/F Opioids constrict the sphincter of Oddi which leads to a decrease in pressure of common bile duct.
FALSE; increase in the pressure of common bile duct
What are the subtypes of opioids? (3) What are they used for?
(1) Mu: morphine-preferring; many of the clinically used opioid drugs are selective for this receptor; mediates spinal and supraspinal analgesia, respiratory depression, miosis, GI effects
(2) Kappa- relevant receptor in spinal cord mediated analgesia
(3) Delta- spinal and supraspinal analgesia
What are the receptor selectivity for the subtypes of opioids? What type of receptors are these?
(1) Mu- endomorphins and B-endorphin (enkephalins, dynorphins)
(2) Kappa- Dynorphins (enkephalins)
(3) Delta- Enkephalins, B-endorphins (dynorphins)
- G-protein coupled receptors -
What are the four genes associated with endogenous opioid peptides? What do they yield?
(1) POMC (pro-opiomelanocortin): yield B-endorphin (met-enkephalin)
(2) Proenkephalin: yield met- and leu-enkephalins
(3) Prodynorphin: yield dynorphin A and B, and alpha and beta neoendorphins (leu-enkephalin)
(4) Pro-endomorphin: putative gene yielding endomorphin-1 and endomorphin-2
What are the opioid receptor effector systems? (3)
(1) Potassium channels: agonists open channels causing neuronal hyperpolarization
(2) Calcium channels: agonists reduce channel opening, thereby inhibiting calcium-dependent neurotransmitter release
(3) Adenylate cyclase inhibition: alterations in regulation of adenylate cyclase activity important in tolerance to opioids
T/F Tolerance to opioids is pharmacokinetic (change in metabolism).
FALSE; pharmacodynamic (cellular response)
