analgesic drugs – lilley – ch 11 cns depressants & muscle relaxants – lilley– ch 13 cns...
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ANALGESIC DRUGS – LILLEY – CH 11
CNS DEPRESSANTS & MUSCLE RELAXANTS – LILLEY– CH 13
CNS STIMULANTS -LILLEY – CH 14
ANTIEPLEPTIC DRUGS – LILLEY – CH 15
ANTIPARKINSONIAN DRUGS – LILLEY -- CH 16
Central Nervous System
CNS Pharmacology Objectives
Discuss the the actions and uses of an opioid agonist, agonist-antagonist, and antagonist
Describe how the nursing process is applied to clients receiving sedative-hypnotic agents
Describe the role of the nurse in promoting client compliance with drug therapy for seizure activity
Identify the variety of conditions and disorders being treated with CNS stimulants
Describe the actions and intended effects of the classes of medications used in the treatment of Parkinson’s disease
CNS- Analgesic AgentsPain
Defn:
Medications that relieve pain without causing loss of consciousness
Painkillers
CNS – Analgesic AgentsPain
Pain
Whatever the patient says it is – Perception
It exists whenever the patient says it exists
It’s an unpleasant sensory and emotional experience associated with actual or potential tissue damage
Pain is a personal and individual experience
CNS– Analgesic AgentsPain
Subjective:
Pain Threshold: The 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 patient can endure without its with
normal function with normal function The point at which the pain becomes unbearable
CNS – Analgesic AgentsClassification of Pain
Classification of pain by onset and duration:
Acute pain: Sudden onset Usually subsides once treated
Chronic pain: Persistent or recurring Often difficult to treat
CNS – Analgesic AgentsClassification of Pain
Classification of Pain Somatic Visceral Vascular Referred Neuropathic Phantom Cancer Psychogenic Central
CNS – Analgesic AgentsPain Transmission
Pain Transmission – Gate Theory Impulses travel from damaged tissues and are
sensed in the brain Many current pain theories are aimed at altering this system
Substances released that stimulate nerve endings: Bradykinin, histamine, potassium, prostaglandins, serotonin
Nerves stimulated: “A” fibers: large fibers covered with myelin sheath, with
rapid conduction – results: sharp & well localized pain “C” fibers: small fibers with no myelin sheath, with slow
conduction – results: dull and non-localized pain
CNS – Analgesic AgentsPain Transmission
Pain fibers enter the spinal cord and travel up to the brain Enter through the dorsal horn – “the gate”
The gate regulates the flow of sensory impulses to the brain
If no impulses are transmitted to higher centers in the brain, there is no pain perception
Activation of “A” fibers - closes the gate Allows the brain to evaluate, identify and localize the
pain & control the gate before it is open Activation of “C” fibers – opens the gate
CNS – Analgesic AgentsPain Transmission
Body has endogenous neurotransmitters Enkephalins Endorphins
Produced by body to fight painBind opioid receptors & inhibit transmission
by “closing the gate”Examples:
Runner’s high Rubbing a painful area stimulates large sensory fibers
– result: gait closed, pain recognition reducedOpiates use the same pathway
CNS – Analgesic AgentsAgonist
Binds to an opioid pain receptor in the brain and causes an analgesic response
CNS – Analgesic AgentsOpioids - Agonists
Chemical Category
Opioid Drugs
meperidine-like drugs
Agonist: merperidine (Demerol, Pethidine), fentanyl (Sublimaze, Durgesic)
Methadone-like drugs
Agonist: C-II Dolphine, propoxyphene
Morphine-like drugs Agonist: C-II: Morphine, Duramorph, Roxanol, MS-Contin, hydromorphone (Dilaudid), oxymorphine, levorphanol, codeine, hydrocodone, oxycodone (OxyContin);C-I: heroin
Opioid/Acetaminophen or ASA Combinations
Agonist: C-II: oxycodone with Tylenol (Percocet); oxycodone with ASA (Percodan); hydrocodone with Tylenol (Vicodin, Lorcet)
CNS – Analgesic AgentsOpioid Analgesics
Opioid pain relievers: Narcotics that contain “opium”, derived from the opium poppy Very powerful Addictive
Indications: PAIN Management alleviate severe to moderate pain Often given with adjuvant analgesic agents to assist pain
relief: NSAIDS, Antidepressants, Anticonvulsants, corticosteroids
Cough center suppression Treatment of diarrhea Balanced anesthesia
CNS –Analgesic AgentsAntagonists
Reverse the effects of these agents on pain receptors
Bind to a pain receptor and exert no response
Also known as competitive antagonists
Medications: naloxone (Narcan) – treat overdose Naltrexone (Trexan) – maintenance of opioid-free state
& psychosocial tx of alcoholism
CNS – Analgesic AgentsSide Effects
EuphoriaCNS depressionNausea and vomitingRespiratory depressionUrinary retentionDiaphoresis and flushingPupil constriction (miosis)ConstipationItching
CNS – Analgesic AgentsOpioid Overdose
Triad
Respiratory depression Respiratory rate <12/min, dyspnea,
diminished breath sounds, or shallow breathing
Decreased level of consciousness
Pinpoint Pupils (miosis)
CNS – Analgesic AgentsOpioid Effects
Tolerance Common physiologic effect of chronic opioid tx Larger doses are required to produce the same level of
analgesia
Physical Dependence Physiologic adaptation of the body to the presence of an opioid
Tolerance and physical dependence are expected with long term opioid treatment, and should not be confused with:
Psychological Dependence Pattern of compulsive drug use characterized by continued
craving for an opioid and the need to use the opioid for effects other than pain relief
CNS – Analgesic AgentsWithdrawal / Abstinence
Syndrome
Occurs when abruptly discontinued or when an opioid antagonist is administered
anxiety, irritability, chills & hot flashes, joint pain, lacrimation, rhinorrhea, diaphoresis, nausea, vomiting, abdominal cramps, diarrhea
CNS – Analgesic AgentsNon-opioids
acetaminophen (Tylenol): blocks peripheral pain impulses by inhibition of prostaglandin synthesis & lowers febrile body temp – hypothalamus Max dose for healthy adult 4,000 mg per day Check combinations of drug products
acetylsalicylic acid (Aspirin): anti-inflammatory, anti-pyretic, analgesic, anti-rheumatic properties Check when ordered with NSAIDs or Plavix
CNS -- Analgesic AgentsNon-steroidal anti-inflammatory drugs
NSAIDs – reduce inflammation Block Leukotriene (lipoxygenase) pathway
Salicylates
Cox1 isoform of the enzyme promotes synthesis of homeostatic prostaglandins Indomethacin (Indocin); ibupofen (Motrin); naproxen
(Naprosyn); nabumetone (Relafen)
Cox2 inhibitors block the cyclooxygenase cox2 pathway - prevent GI side effects Celecoxib (Celebrex)
CNS – Analgesic AgentsMedication Orders
Joint Commission Requirements
Pain medication for severe, moderate, and/or mild pain
Example:
Morphine 5 mg IM q4h prn severe painPercocet 1-11 tablets q6h prn moderate painTylenol 650 mg po q4h prn mild pain
CNS – Analgesic AgentsInteractions
Dangerous interactions may occur if taken with alcohol
Should not be taken in the presence of: Liver dysfunction Possible liver failure When taking other hepatotoxic drugs
CNS – Analgesic AgentsNursing Implications
Assessment Allergy History / Idiosyncratic Reactions History of alcohol use Medical history – possible contraindications Medication reconciliation – possible drug interactions Thorough pain assessment – Fifth Vital Sign
Intensity, character, onset, location, description, precipitating and relieving factors, type, remedies, and other pain treatments
Pain Scale / Nonverbal Baseline vital signs and pulse oximetry Monitor for side effects, change in pt status, & status
of pain relief
CNS – Analgesic AgentsNursing Implications
Patient Education
Do not take other medications or OTC medications unless prescribed by physician
Pain scale Signs & Symptoms of drug allergies or adverse effects Safety measures Pain management – includes both pharmacologic and non-pharmacologic approaches:
Position of comfort, distraction, therapeutic touch, comfort foods & beverages, visitors, spirituality, presence!
CNS – Analgesic AgentsNursing Implications
Nursing Actions:
Administer oral forms with food to minimize gastric upset Ensure safety measures – prevent orthostatic hypotension Withhold dose and contact physician with any change in pt
status Check dosages carefully Follow proper administration guidelines – po, sq, IM, IV –
including dilution, rate of administration Side Effects: constipation – increase fluids, stool softeners
CNS – Analgesic AgentsNursing Implications
Monitor for therapeutic effects
Decreased complaint of pain Decreased severity of pain Increased periods of comfort Improved activities of daily living, appetite, and sense
of well-being Decreased fever (acetaminophen & NSAIDs)
CNS – Analgesic Agents
For the best results in treating severe pain associated with pathologic spinal fractures related to metastatic bone cancer, which type of dosage schedule should be used? Plan medication administered:
a. As needed.b. Around the clock.c. On schedule during waking hours only.d. Around the clock, with added doses as needed
for breakthrough pain.
CNS Analgesic Agents
A patient is receiving an opioid via a PCA pump as part of the postoperative pain management program. During rounds, the nurse notices that his respirations are 8 breaths per minute and he is extremely lethargic. After stopping the opioid infusion, what should the nurse do next?
a. notify the charge nurseb. administer oxygenc. administer an opiate antagonist per standing ordersd. perform a thorough assessment, including mental
status examination