Analgesic Agents Flashcards
What are A fibers?
Fibers that carry perception of vibration, stretch and pressure.
There are four types : Alpha, Beta, Delta and Gamma.
What is A-delta fibers?
Fibers that carry the sensation of pain to the spinal cord - usually acute sharp pain.
What are C Fibers?
Unmyelinated nerve fibers - these have a slower conduction due to being unmyelinated. They also carry pain sensation, however it is more of a slow, dull and aching pain.
What is Ergot derivative?
Drug that helps with migraines by causing vasoconstriction in the brain and peripheral areas., however there are a lot of adverse effects associated with these.
What is the gate control theory
The concept that pain is not just about how much damage the tissues receive, but about how pain is transmitted though the nerve fibers and there are ways that we can close the pain gate with alternative means.
For example: if those nerve fibers are stimulated via massage or heath, they are distracted and won’t send the pain signal, or the pain signal will be overwhelmed by the other signals.
What is a Migraine Headache?
Severe unilateral pain in the head that leads to other effects such as nausea, vomiting and photophobia and is usually caused by arterial dilation.
What’s Nociception?
Transmission of unpleasant stimuli to the brain.
What are opioid agonists?
Drugs that enhance opioid receptors
What are opioid agonists-antagonists?
Drugs that both enhances and decreases opioid receptors site activity. They will enhance some sites while inhibiting other sites.
What are opioid antagonists?
Drugs that block opioid receptor sites - these are used to treat opioid OD’s.
What are opioid receptors?
The nerve receptor sites that react with endorphins and encephalins, which are the same sites that react to opioid drugs.
Define pain.
Sensory and emotional experience associated with actual or potential tissue damage
What is the Spinothalamic tract?
The nerve pathway that travels from the spine through the thalamus to the brain,
What is Triptan?
a selective serotonin blocker that causes vasoconstriction in the brain and it is used as medication for migraines.
What is pain?
Pain can be physical or emotional and differs from person to person. Each person perceives it differently.
what can often affect the treatment that patients receive by nurses for their pain?
Preconceived notions of pain by the nurse. This can often result in the patient not getting the treatment that they need. When a patient tells us that they are in pain, we need to take it seriously. This is especially prevalent in the different socioeconomic groups.
What are two times of pain duration?
Acute & Chronic
What is acute pain normally caused by?
Generally cause by new tissue damage. Its letting you know that an injury has occured and you should stop doing the thing that is causing the injury or get away from it.
How do we define chronic pain?
Can be consistent or inconsistent and usually last longer than 3 months. It can affect a persons ADL’s, interrupt sleep and reduce quality of life.
How does drugs used to relieve pain work?
All intended to interrupt or distort the perception of pain in the brain and spinal cord in some way. It works in the CNS to alter the way pain impulses are processed.
Why do we use opioids?
Opium derivatives used to treat many types of pain
What do we use Antimigraine Drugs for?
Reserved for the treatment of migraine headaches.
Explain the Gate- Control Theory of pain in detail.
Its the idea that if we look at how pain is transmitted through the different nerves and nerve types. we can interrupt the pain signal, particularly if we stimulate the A fibers.
The Delta A fibers are responsible for acute pain, and so we can overpower these smaller slower A delta pain signals by stimulating the A fibers more.
The pain signals being sent out from the CNS can be modified using norepinephrine and serotonin, which is why some antidepressants can work for pain management.
What is the reason pain can differ from person to person?
There are many factors that can affect the descending pain signal. some of these are learned experiences, cultural expectations, individual tolerance and the placebo effect.
This is who some treatments work well for some patients and not at all for others.
Other than pain what other things does opioid receptors control?
Pupil size, GI secretions and the effect of chemo receptor trigger zone which controls nausea, vomiting, breathing and coughing
What are the two types of opioid receptors?
Mu and Kappa
What does the MU receptors control?
mostly pain blocking receptors that can also give a feeling of euphoria and cause lower GI motility, pupil constriction, respiratory depression and dependance.
What does Kappa receptors control?
They give some pain relief, and also causes pupil constriction, sedation and dysphoria (general feeling of unease, dissatisfaction or discomfort)
Where are opioid receptors found?
○CNS
○Nerves in the periphery
○Cells in the gastrointestinal (GI) tract
○CTZ - chemoreceptor trigger zone
What are some lifespan considerations that we should keep in mind when administering opioids to children?
- Safety and efficacy not established - use only if necessary.
- Dosage should be carefully calculated
- Monitor closely for ADE
- Methadone should not be used in children and if an alternative is needed an opioid agonist antagonist that can be used is buprenorphine.
What are some lifespan considerations that we should keep in mind when administering opioids to adults?
○Encourage to request pain medication before pain out of control
○Caution in pregnancy/lactation
○Narcotics used during labor- monitor mom and baby closely for ADE
What are some lifespan considerations that we should keep in mind when administering opioids to older adults?
○More likely to experience ADE
○More likely to develop toxicity
○Implement safety measures such as fall prevention.
What is the antidote for an opioid overdose?
Naloxone (Narcan)
When is the best time to take the opioids when taken for pain?
Before the pain becomes unbearable - waiting too long can cause breakthrough pain and it can take longer to get pain under control.
Can we use opioids during labor?
Yes, up until a certain point. After 6 cm of dilation the drug will be passes to the baby and can cause CNS depression if the baby is born shortly after mom has received opioids.
What can happen if Mom is taking opioids regularly during pregnancy?
Babies can develop withdrawal symptoms after they’re born., because now they are no longer getting opioids. Withdrawal usually happens 24-72 hrs after delivery depending on their exposure in the womb.
What will women with an opioid addiction start during pregnancy?
A methadone treatment program, and although the babies will have withdrawal symptoms the methadone reduces the severity.
Define Opioid Agonists.
●Drugs that stimulate opioid receptors
●Cause analgesia, sedation, or euphoria
●Potential for physical dependence
●Controlled substances
●Rising problem of addiction
What drug classes under Opioid Agonists do we need to know?
Morphine,
Hydromorphone,
Codeine,
Oxycodone,
Fentanyl,
Hydrocodone
What are the MOA’s for Opioid Agonists?
○Act at specific opioid receptor sites in the CNS
○Produce analgesia, sedation, and a sense of well-being
Why would we give Opioids Agonists to patients?
- Relief of severe acute or chronic pain
- Analgesia during anesthesia
- A patient can also get a PCA to give themselves doses of opioids after surgery. It takes two nurses to set this up.
What are some factors that would contraindicate the use of Opioid Agonists?
- Allergy
- Diarrhea caused by poisons - this is because and opioid agonist will cause decreased GI motility, whihc will increase poison absorption. This is also why we should be careful in giving opioids to patients with GI obstruction or patients recovering from GI surgery.
What pre-existing patient conditions would prompt us to use caution when administering opioid agonists?
○Respiratory dysfunction, asthma, emphysema - can worsen due to respiratory depression effect.
○Pregnancy, labor, lactation
○GI or GU surgery - will complicate recovery by retaining urine and stool.
* GI obstruction will become worse with decreased motility.
○Acute abdomen or ulcerative colitis - can be masked
○Head injuries, alcoholism, delirium tremens, or CVA - can mask
What are some symptoms of acute onset of severe abdominal pain that opioids can mask?
Pain
Tenderness
Changes in bowel sounds.
If you are performing a neuro assessment to patients who are suffering from head injuries, alcoholism, delirium tremens, or a stroke, and these patients have been given opioids, how do you evaluate if they are acting differently due to these conditions or due to the opioids that were given?
You can’t, which is why is should not be given in these patients unless necessary and diagnosis has been established.
By impairing consciousness and cognitive functioning what can opioids complicate?
Assessment of neurological status in head injury patients.
Opioids can exacerbate confusion and agitation whihc makes management of delirium tremens more challenging.
May worsen neurological outcomes by causing sedation and impairing the patient’s ability to respond to stimuli.
What are some known adverse reactions to opioid agonists?
- Respiratory depression which can lead to apnea, cardiac arrest or shock.
- GI motility and CTZ stimulation can lead to nausea & vomiting & constipation,
- CNS effect such as dizziness, fear, anxiety and hallucinations.
- orthostatic hypotension - ensure aid in position changes and ambulation.
Are there any DDI’s to opioid agonists, and if so, what are they?
- Barbiturate general anesthetics - risk of respiratory depression, hypotension, sedation and coma.
- SSRIs - Increased risk of serotonin syndrome.
- Cholinergic Agents and HTN agents - can case increase in GI effect and Hypotension.