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مشاهدة النسخة كاملة : Analgesic narcotics


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02-28-2013, 06:32 PM
Analgesic narcotics
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Article ************************ives






Outline the gate theory of pain and explain therapeutic ways to block pain using the gate theory.
Describe the therapeutic actions, indications, pharmacokinetics, contraindications, most common adverse reactions, and important drug–drug interactions associated with narcotics .
Discuss the use of narcotics ***** across the lifespan.
Compare and contrast the prototype ***** morphine, pentazocine, naloxone.
Outline the nursing considerations, including important teaching points, for patients receiving a narcotic .


Pain

Pain, by definition,
is a sensory and emotional experience associated with actual or potential tissue damage.
The narcotic analgesics ***** are involved in the management of severe pain, whether acute or chronic, all of which work in the central nervous system (CNS)—the brain and the spinal cord—to alter the way that pain impulses arriving from peripheral nerves are processed.

Pain perception

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When tissue is injured, various chemicals are released and pain results. These chemicals, includes kinins and prostaglandins
A-delta and C fibers carry pain impulses to the spinal cord.
According to the gate theory of pain, impulses travel from the spine to the cortex via tracts that can be modulated along the way at specific gates.

Gate theory

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Opioid Receptors



Opioid receptors; are receptors found in CNS (spinal cord and thalamus); these receptors help integrate and relate incoming information about pain.
They are activated both by


endoge**usly[naturally] produced opioid peptides (endorphins and the enkephalins), and by
exoge**usly administered opiate compounds[ analgesic narcotics].
Activation of this receptors leads to blocking of pain perception.
Opioids, narcotics



Narcotics are derived from the opium plant; they bind to opioid receptors to


relieve pain [ analgesic effect]
Sedation
and promote feelings of well-being or euphoria.
The (µ) mu-receptors which are subtypes of opioid receptors ;are primarily pain-blocking receptors.
Besides analgesia, and euphoria mu-receptors also account for.


respiratory depression,
decreased GI activity,
pupil constriction, and
the development of physical dependence.
Because of the potential for the development of physical dependence and addiction while taking these *****, the narcotic agonists are classified as
controlled substances.


The degree of control is determined by the relative ability of each drug to cause physical dependence [addiction].

Schedules of Controlled Substances



The Controlled Substances are ***** that are k**wn to have abuse potential.
The controlled ***** are divided into five schedules based on their potential for abuse and physical and psychological dependence.
Schedule I


High abuse potential and ** accepted medical use (heroin, marijuana, LSD)
Schedule II


High abuse potential with severe dependence liability (narcotics, amphetamines, and barbiturates)
Schedule III


Less abuse potential than schedule II ***** and moderate dependence liability (**nbarbiturate sedatives, **namphetamine stimulants, limited amounts of certain narcotics)
Schedule IV


Less abuse potential than schedule III and limited dependence liability (some sedatives, antianxiety agents, and **n-narcotic analgesics)
Schedule V (C-V):


Limited abuse potential. Primarily small amounts of narcotics (codeine) used as antitussives or antidiarrheals.

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Available narcotic Agonists



Codeine ;


indication
relief of mild to moderate pain;
As antitussive in case of coughing induced by mechanical or chemical irritation of the respiratory tract.
Fentanyl ;


Indications
for analgesia before, during, and after surgery;
transdermal ***** for management of chronic pain
Narcotic analgesia for patients on mechanical ventilators at ICU.
Morphine;


Indications
Relief of moderate to severe chronic and acute pain;
preoperatively and postoperatively.
oxymorphone
remifentanil
sufentanil

Therapeutic Actions and Indications

Indications for narcotic agonists include


relief of severe acute or chronic pain[ pain of acute myocardial infarction, pain in patients suffering from malignancy]
preoperative medication,
analgesia during anesthesia,
as antitussives

Pharmacokinetics



Intrave**us (IV) administration is the most reliable way to achieve therapeutic levels of narcotics.
These ***** undergo hepatic metabolism and are generally excreted in the urine and bile.

Adverse Effects



Respiratory depression with apnea, cardiac arrest, and shock may result from narcotic-caused CNS respiratory depression.
GI effects as


constipation ,
nausea, vomiting, and
biliary spasm
urinary retention

Contraindications and Cautions



C/ I;


presence of any k**wn allergy to any narcotic agonist;
pregnancy, labor, or lactation
after biliary surgery or surgical anastomoses because of the effect of narcotics on GI tract which leads to GI depression .
Caution


patients with respiratory dysfunction e.g heavy *****r or asthmatic patients .
recent GI or genitourinary GU surgery;
head injuries,
cerebral vascular disease, which could be exacerbated by the CNS effects of the *****;

Narcotic Antagonists[antidote]



Are ***** that bind strongly to opioid receptors, but they do **t activate the receptors.
Indications


blocking unwanted adverse effects associated with narcotics, such as respiratory depression,
treatment of narcotic overdose.
Type


Naloxone (Narcan) is used IV, IM, or SC .
Reminder


Antidote of benzodiazepine (valium) is
Flumazenil (anexate),


Antidote of morphine
Naloxone (narcan)

Nursing Considerations for Patients Receiving Narcotic Agonists

Assessment: History and Examination


Screen for the following conditions, which could be cautions or contraindications for the use of the drug:


any k**wn allergies to these *****;
respiratory dysfunction;
GI or biliary surgery;
renal or hepatic dysfunction.
Examinations ;Include screening for baseline status before beginning therapy and for any potential adverse effects. Assess the following:


pulse, blood pressure, and cardiac function
CNS; orientation, affect, reflexes,
Pupil size;
Respiration and adventitious sounds;
Bowel sounds and reported output;
Bladder palpation and voiding pattern.
Check liver and renal function tests,
electroencephalogram (EEG) and
electrocardiogram (ECG) as appropriate.

Implementation with Rationale



Provide a narcotic antagonist and equipment for assisted ventilation on standby during IV administration to support the patient in case severe reaction occurs.
Use extreme caution when injecting a narcotic into any body area that is chilled or has poor perfusion or shock because absorption may be delayed. After repeated doses, an excessive amount is absorbed all at once.
Use additional measures for relief of pain, such as


back rubs,
stress reduction,
hot packs, and ice packs to increase the effectiveness of the narcotic and reduce pain.
Reassure patients that the risk of addiction is minimal. Most patients who receive narcotics for medical reasons do **t develop dependency syndromes.
Provide thorough patient teaching, including drug name and prescribed dosage, measures for avoidance of adverse effects,

Focus Points



Narcotic agonists react with opioid receptor sites to stimulate their activity;
Narcotic antagonists are used to treat narcotic overdose or to reverse unacceptable adverse effects.
Points to Remember



Pain occurs any time that tissue is injured and various chemicals are released.
The pain impulses are carried to the spinal cord by small-diameter A-delta and C fibers,
Opioid receptors, which are found throughout various tissues in the body, but specially in the CNS ,react with endoge**us endorphins and enkephalins to modulate the transmission of pain impulses.
Narcotics, derived from the opium plant, react with opioid receptors to relieve pain. In addition, they lead to constipation, respiratory depression, sedation, and suppression of the cough reflex, and they stimulate feelings of well-being or euphoria.
Because narcotics are associated with the development of physical dependence [addiction], they are controlled substances.
Narcotic agonists react with opioid receptor sites to stimulate their activity.
Narcotic antagonists, which work to reverse the effects of narcotics, are used to treat narcotic overdose or to reverse unacceptable adverse effects.