Chapter 10: Analgesic Drugs Flashcards
Analgesics
- Medications that relieve pain without causing loss of consciousness
- “Painkillers”
- Opioid analgesics
- Adjuvant analgesic drugs
Pain
An unpleasant sensory and emotional experience associated with actual or potential tissue damage
* A personal and individual experience
* Whatever the patient says it is
* Exists when the patient says it exists
* Pain involves:
* Physical factors
* Psychologic factors
* Cultural factors
Pain Management Approach
No single approach to effective pain management
* Tailored to each patient’s needs
* Consider:
* Cause of pain
* Existence of concurrent medical conditions
* Characteristics of pain
* Psychological and cultural characteristics
* Requires ongoing reassessment of pain and the effectiveness of treatment
Pain Threshold
Level of stimulus needed to produce the perception of pain
* A measure of the physiologic response of the nervous system
Pain Tolerance
The amount of pain a person can endure without it interfering with normal function
* Varies from person to person
* Subjective response to pain, not a physiologic function
* Varies by attitude, environment, culture, ethnicity
Acute pain
- Sudden onset
- Usually subsides once treated
Chronic pain
- Persistent or recurring
- Lasts 3 to 6 months
- Often difficult to treat
- Tolerance
- Physical dependence
Pain Transmission
- The nerve impulses enter the spinal cord and travel up to the brain.
- The point of spinal cord entry or the “gate” is the dorsal horn.
- This gate regulates the flow of sensory impulses to the brain.
- Closing the gate stops the impulses.
- If no impulses are transmitted to higher centers in the brain, there is no pain perception
- Body has endogenous neurotransmitters.
- Enkephalins
- Endorphins
- Produced by body to fight pain
- Bind to opioid receptors
- Inhibit transmission of pain by closing gate
- Rubbing a painful area with massage or liniment stimulates large sensory fibers.
- Result
- Closes gate
- Reduces pain sensation
Treatment of Pain in Special Situations
- PCA and “PCA by proxy”
- Patient comfort vs. fear of drug addiction
- Opioid tolerance
- Use of placebos
- Recognizing patients who are opioid tolerant
- Breakthrough pain
- Synergistic effect
Adjuvant Drugs
- Assist primary drugs in relieving pain
- NSAIDs
- Antidepressants
- Anticonvulsants
- Corticosteroids
- Example: adjuvant drugs for neuropathic pain
- Amitriptyline (antidepressant)
- Gabapentin or pregabalin (anticonvulsants)
Opioid Drugs
- Synthetic drugs that bind to the opiate receptors to relieve pain
- Mild agonists: codeine, hydrocodone
- Strong agonists: morphine, hydromorphone, oxycodone, meperidine,
fentanyl, and methadone - Meperidine: not recommended for long- term use because of the accumulation of a neurotoxic metabolite, normeperidine, which can cause seizures
MOA: binds to opioid receptors in the body
Equianalgesia
- Ability to provide equivalent pain relief by calculating dosages of different drugs or routes of administration that provide comparable analgesia
- Hydromorphone (Dilaudid): seven times more potent than morphine
- Example: if morphine 10 mg was given to a patient followed 1 hour later by hydromorphone 1 mg, then the patient would have received an equivalent of 17 mg of morphine.
A patient diagnosed with cholecystitis reports pain in the back and scapular areas. The nurse infers that the patient has which type of pain?
Referred pain
what is the PRIMARY indication for the administration of morphine?
to relieve acute and chronic pain
Medication used to treat patient experiencing severe adverse effects of an opioid analgesic.
Naloxone
