Neuro Pharmacology

7/29/2019 Neuro Pharmacology

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Neuro pharmacology

Chapters

10,11, 12,16


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Opioid Analgesics

Pain relievers that contain opium, derived

from the opium poppy or chemically related

to opium

Narcotics: strong pain relievers


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Terminology

Analgesics: medication that relieves painwithout causing a loss of conciousness

Pain: whatever the patient says it isPain threshold:level of stimulus that results in

the perception of pain

Pain tolerance: the amount of pain anindividual can endure without interferinfwith normal functionning


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Terminology cont

Acute pain: sudden onset

Chronic pain: persistent of recurring


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Opioid Analgesics (contd)

codeine sulfate

meperidine HCl

methadone HCl

morphine sulfate

propoxyphene HCl


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Opioid Analgesics:

Indications Main use: to alleviate moderate to severe

pain

Often given with adjuvant analgesic agents toassist the primary agents with pain relief

NSAIDs

AntidepressantsAnticonvulsants

Corticosteroids


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Opioid Analgesics:

Indications (contd)Opioids are also used for:

Cough centre suppression

Treatment of diarrhea

Balanced anaesthesia


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Opioid Analgesics:

Contraindications Known drug allergy

Severe asthma or other respiratory

insufficiency

Elevated intracranial pressure Pregnancy


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Opioid Analgesics:

Side Effects Euphoria

CNS depression

Nausea and vomiting Respiratory depression

Urinary retention

Diaphoresis and flushing

Pupil constriction (miosis) Constipation

Itching


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Opiate Antagonists

Naloxone, Narcan

Opiate antagonists

Bind to opiate receptors and prevent a response

Used for complete or partial reversal of opioid-induced

respiratory depression


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Opiates

Opoid tolerance: a common physiological result of

chronic opioid treatment. Larger dose of opioids is

required to maintain the same level of analgesia Opoid physical dependance:The physiological

adaptation of the body to the presence of an opioid

Opoid phsychological dependance:A pattern of

compulsive drug use characterized by a continued

craving for an opioid and the need to use the

opioid for effects other than pain relief


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Opiates

Opioid tolerance and physical dependence

are expected with long-term opioid

treatment and should not be confused withpsychological dependence (addiction)

*Misunderstanding of these terms leads to

ineffective pain management andcontributes to the problem of under

treatment


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Opioid Analgesics:

Nursing Implications Oral forms should be taken with food to

minimize gastric upset

Ensure safety measures, such as keepingside rails up, to prevent injury

Withhold dose and contact physician if

there is a decline in the clients condition orif VS are abnormal, especially if respiratoryrate is less than 12 breaths/minute


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Opioid Analgesics:

Nursing Implications (contd) CHECK DOSAGES CAREFULLY

Follow proper administration guidelines for IM injections,

including site rotation

Follow proper guidelines for IV administration, including

dilution, rate of administration, institutions

IV drug manual


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Opioid Analgesics:

Nursing Implications (contd)

Constipation is a common side effect andmay be prevented with adequate fluid andfibre intake

Instruct clients to follow directions foradministration carefully, and to keep arecord of their pain experience andresponse to treatments

Clients should be instructed to change positionsslowly to prevent possibleorthostatic hypotension


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Monitor for Side Effects

Should VS change, clients conditiondecline, or pain continue, contact physician

immediately Respiratory depression may be manifested

by respiratory rate of less than 12/minute,dyspnea, diminished breath sounds, orshallow breathing


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Nonopioid Analgesics

Acetaminophen

Analgesic and antipyretic effects

little anti-inflammatory effects

Available OTC and in combination products

with opioids


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Mechanism of Action

Similar to salicylates

Blocks pain impulses peripherally by

inhibiting prostaglandin synthesis

Indications:

Mild to moderate pain fever Alternative for those who cannot take

aspirin products


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Acetaminophen

Contraindications

Drug allergy

Severe liver disease

Genetic disease (G6PD)


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Toxicity and Managing Overdose

Even though available OTC, lethal when

overdosed

Overdose, whether intentional or due to chronicunintentional misuse, causes hepatic necrosis

Long-term ingestion of large doses also causes

nephropathy

Recommended antidote: acetylcysteine


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Dosage

Maximum daily dose for healthy adults is

4000 mg per day

Inadvertent excessive doses may occurwhen different combination drug products

are taken together

Be aware of the acetaminophen content ofthe medications taken by the client


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Interactions

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


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Analgesics:

Nursing Implications (contd) Perform a thorough pain assessment,

including pain intensity and character,

onset, location, description, precipitatingand relieving factors, type, remedies, and

other pain treatments

Assessment of pain is now being considered afifth vital sign


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Analgesics:

Nursing Implications (contd) Be sure to medicate clients before the pain

becomes severe in order to provide

adequate analgesia and pain control Pain management includes pharmacological

and nonpharmacological approaches; be

sure to include other interventions asindicated


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Analgesics

Case Study Mr. Jones is admitted with Renal Colic. He

rings his bell stating he cant take in

anymore? What are your assessments?


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Analgesics

Case Study cont Your MAR indicates that Mr Jones may

have IV Morphine 2mg q 10 minutes for

pain.

What will you do before administering this

medication?


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Analgesics

Case Study cont He settles after 4 doses. What will you do

now?

What teaching will you provide about pain

management?

What teaching will you provide about

narcotic analgesics?


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Morphine

is an highly potent opiat analgesic

PO, S/C, IM, IV

Indications: post op pain

Chronic pain

Kidney stone pain

Adjunct to General anesthesia intrathecal analgesia

Palliative

Antitussive

Diarrhea


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Analgesics

Case Study cont On the next shift Mr Jones has a re-

occurence of pain. The nurse gives in 5

doses of IV morphine, (total fo 10 mg). He finally settles.

While checking in on him, he his

unconctious, responding to painful stimulionly and his respirations are 6/minutes.


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Codeine

Opiate analgesic

Routes: PO, IM, SC

Indications: post op pain

Chronic pain

Palliative Antitussive

Diarrhea


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Codeine

Present in numerous combination drugs

Tylenol #1acetaminophen 300 mgcaffeine 15 mg, in combination withcodeine 8 mg

Tylenol #2 acetaminophen 300 mgcaffeine 15 mg, in combination with

codeine 15 mg Tylenol#3 acetaminophen 300mg, caffeine 15mg,Codeine 30mg

Codeine Contin


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Others

Percocet: oxycodone andacetaminophen

Percodan: oxycodone/Aspirin


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Anaesthetics

Agents that depress the central nervous

system (CNS)

Depression of consciousness

Loss of responsiveness to sensory stimulation

(including pain)

Muscle relaxation Anaesthesia: the state of depressed CNS

activity


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Anaesthesia

A state of depressed CNS activity

Two types

General anaesthesia

Local anaesthesia



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Types of anesthetics

General anesthetic: agents that induce

global anesthesia with loss of conciousness

Local anesthesia; agents that cause aspecific area of the body to be insensitive to

pain without affecting consciousness

Topical anesthetic: local anesthetics directlyapplied to skin and mucous membranes.


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General Anaesthetics

Agents that induce a state in which the CNS

is altered to produce varying degrees of:

Pain relief

Depression of consciousness

Skeletal muscle relaxation

Reflex reduction


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Local Anaesthetics

Also called regional anaesthetics

Used to render a specific portion of the body

insensitive to pain

Interfere with nerve impulse transmission to

specific areas of the body

Do not cause loss of consciousness


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Types of Local Anaesthesia

Epidural

Infiltration

Nerve block

Spinal

Topical


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Moderate Sedation

Neurolept anesthesia Combination of an IV benzodiazepine and

an opiate analgesic used

Anxiety and sensitivity to pain are reduced,and client cannot recall the procedure

Preserves the clients ability to maintain

own airway and to respond to verbalcommands


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Moderate Sedation (contd)

Used for diagnostic procedures and minor

surgical procedures that do not require deep

anaesthesia. (ie endoscopy) Topical anaesthetic may be applied also

Rapid recovery time and greater safety

profile than general anaesthesia


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Nursing Implications

Always assess past history of surgeries and

response to anaesthesia. Any known

problems such as difficult intubation,N&V, malignant hyperthermia?

Assess past history, allergies, medications

Assess use of alcohol, illicit drugs, opioids


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Assessment is vital during pre-, intra-, and

postoperative phases

Vital signs

Baseline labwork, ECG

Pulse oximeter (PO2)

ABCs (airway, breathing, circulation)Monitor all body systems


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Nursing considerations during the

perioperative phase include the:

Preoperative phase

Intraoperative phase

Postoperative phase

Each phase has its own complex andspecific nursing actions


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Close and frequent observation of the client

and all body systems

During a procedure, monitor vital signs,ABCs

Watch for sudden elevations in body

temperature, which may indicate malignanthyperthermia


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During recovery, monitor for cardiovascular

depression, respiratory depression, and

complications of anaesthesia

Monitor for S&S of bleeding

Implement safety measures during recovery,especially if motor/sensory loss occurs due to

local anaesthesia


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Reorient client to surroundings

Provide preoperative teaching about thesurgical procedure and anaesthesia

Teach the client about postoperative

turning, coughing, deep breathing


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CNS Depressants

Sedatives or Hypnotics

Sedatives: reduce nervousness, excitability

and irritability without causing sleep

Hypnotic: causes sleep


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CNS Depressants (contd)

Sedative-hypnoticsdose dependent

At low doses, calm or soothe the CNS

without inducing sleep

At high doses, calm or soothe the CNS to the point

of causing sleep


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Sedative-Hypnotics

3 main categories:

1. Barbtuates

2. Benzodiazepine

3. Miscellaneous agents


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Sedative-Hypnotics:

Barbiturates First introduced in 1903; standard agents for

insomnia and sedation

Habit forming Only a handful commonly used today due in

part to the safety and efficacy ofbenzodiazepines

Barbiturates have a narrow therapeuticindex

B bi I di i


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Barbiturates: Indicationspentobarbital

phenobarbital

Hypnotic

Sedative

Anticonvulsant

Anaesthesia for surgical procedures


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Barbiturates: Side Effects

Body System Effects

CNS Drowsiness, lethargy,

vertigo, mental depression,coma

Respiratory Respiratory depression,

apnea, bronchospasms,

cough


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Barbiturates:

Toxicity and Overdose Overdose frequently leads to respiratory

depression, and subsequently, respiratory

arrest Overdose produces CNS depression (sleep

to coma and death)

Can be therapeutic

Anaesthesia induction

Uncontrollable seizures: phenobarbital coma


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CNS Depressants:

BenzodiazepinesMost frequently prescribed sedative-hypnotics

Most commonly prescribed drug classes

Favourable side effect profiles

Efficacy

Safety


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Benzodiazepines:

Classification Classified as either:

Sedative-hypnotic

Anxiolytic (medication that relieves anxiety)


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Benzodiazepines:

Sedative-Hypnotic TypesLong acting

chlordiazepoxide, clorazepate, flurazepam

Intermediate actingalprazolam, clonazepam, lorazepam, oxazepam

Short acting

midazolam (IV), triazolam


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Benzodiazepines:

Drug Effects Calming effect on the CNS

Useful in controlling agitation and anxiety

Reduce excessive sensory stimulation,

inducing sleep

Induce skeletal muscle relaxation


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Benzodiazepines:

Indications Sedation

Sleep induction

Skeletal muscle relaxation Anxiety relief

Treatment of alcohol withdrawal

Agitation Depression

Epilepsy



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Benzodiazepines: Side Effects

Mild and infrequent

Headache

Drowsiness Dizziness

Vertigo

Lethargy

Paradoxical excitement (nervousness)

Hangover effect


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Nursing Implications

Give 15 to 30 minutes before bedtime for

maximum effectiveness in inducing sleep

Most benzodiazepines (except flurazepam)cause REM rebound and a tired feeling the

next day; use with caution in the elderly

Clients should be instructed to avoidalcohol and other CNS depressants


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It may take 2 to 3 weeks to notice improved

sleep when taking barbiturates

Rebound insomnia may occur for a fewnights after a 3- to 4-week regimen has been

discontinued


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Safety is important

Keep side rails up or use bed alarms

Do not permit smokingAssist client with ambulation (especially the

elderly)

Keep call light within reach Monitor for side effects


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Monitor for therapeutic effects

Increased ability to sleep at night

Fewer awakeningsShorter sleep-induction time

Few side effects, such as hangover effects

Improved sense of well-being because ofimproved sleep


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Muscle Relaxants

Baclofen, Flexeril, Dantrolene Act to relieve pain associated with skeletal muscle

spasms

Majority are central acting CNS is the site of action

Similar in structure and action to other CNS

depressants

Direct acting Acts directly on skeletal muscle

Closely resembles GABA


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Muscle Relaxants: Indications

Relief of painful musculoskeletal conditions

Muscle spasms

Management of spasticity of severe chronicdisorders

Multiple sclerosis, cerebral palsy

Work best when used along with physicaltherapy


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Muscle Relaxants: Side Effects

Extension of effects on CNS and skeletal muscles

Euphoria

Lightheadedness

Dizziness

Drowsiness

Fatigue

Muscle weakness

treatment of convulsions and status epilepticus


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CNS Stimulants

Drugs that stimulate a specific area of the brainor spinal cord.

Analeptics (CNS stimulants) Appetite suppressants

Treatment of

Attention-deficit/hyperactivity disorder (ADHD)Narcolepsy

Migraine headache


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Indications

Analeptics (CNS stimulants) Reversal of anaesthesia-

induced respiratory depression

Anorexiants Thought to suppress the appetite controlcentre in the brain

ADHDStimulate the areas in the brain responsible for

mental alertness and attentivenessNarcolepsyIncrease mental alertness

Migraine headaches

Caffeine, co-administered with other drugs, used to


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Side Effects

Wide range, dose related

Tend to speed up body systems

Common adverse effects include:

Palpitations, tachycardia, hypertension, angina,

dysrhythmias, nervousness, restlessness,

anxiety, insomnia, nausea, vomiting, diarrhea,increased urinary frequency

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