anesthetics, analgesics, and narcotics

Chapter 6

Anesthetics, Analgesics, and Narcotics

By SANJAY RAJPUROHIT

Chapter 6 Topics

• Divisions of the Nervous System• Major Neurotransmitters• Anesthesia

– General Anesthesia– Local Anesthesia

• Pain Management• Migraine Headaches

Learning Objectives

• Understand the central and peripheral nervous systems, their functions, and their relationship to drugs.

• Become aware of the role of neurotransmitters.• Learn how drugs affect body systems and where

they work in the body.• Understand the concepts of general and local

anesthesia, and know the functions of these agents.

Learning Objectives

• Define the action of neuromuscular blocking agents in reducing muscle activity.

• Distinguish between narcotic and nonnarcotic analgesia.

• Become familiar with the various types of agents for migraine headaches.

Divisions of the Nervous System

• Central Nervous System– Brain– Spinal cord

• Peripheral Nervous System– Nerves– Sense organs


• Central Nervous System1. Brain receives information

2. Evaluates information

3. Sends out a response

• Peripheral Nervous System


• Central Nervous System

• Peripheral Nervous System– Somatic Nervous System– Autonomic Nervous System


• Central Nervous System

• Peripheral Nervous System– Somatic Nervous System

Voluntary action: skeletal muscle contraction and movement

– Autonomic Nervous SystemInvoluntary activities: respiration, circulation, digestion, sweating

Autonomic Nervous System

Review

The nervous system has two components. What are they?

Review

The nervous system has two components. What are they?

Answer – Central nervous system (CNS)– Peripheral nervous system (PNS)

Major Neurotransmitters

• Acetylcholine

• GABA

• Dopamine

• Epinephrine

• Serotonin


• Acetylcholine (ACh)– Smooth muscle, cardiac muscle, and

exocrine glands

– Anticholinergics block ACh receptors• GABA

• Dopamine

• Epinephrine

• Serotonin


• Acetylcholine

• GABA (gamma-aminobutyric acid)

Regulates message delivery system of the brain

• Dopamine

• Epinephrine• Serotonin


• Acetylcholine• GABA

• DopamineActs on the CNS and kidneys

• Epinephrine• Serotonin


• Acetylcholine• GABA• Dopamine

• Epinephrine–Acts on cardiac and bronchodilator

receptors–Known as Adrenaline

• Serotonin


• Acetylcholine• GABA• Dopamine• Epinephrine

• Serotonin– Acts on smooth muscle and gastric mucosa

(causes vasoconstriction)

– Emotional responses: depression, anxiety

Communication by Neurotransmitters

Neurotransmitters are released from one axon and received by another neuron’s dendrites.

Discussion

What are three important types of receptors in the study of drugs?

Discussion

What are three important types of receptors in the study of drugs?

Answer – Alpha– Beta-1– Beta-2

Types of Receptors

• AlphaVasoconstriction, raise BP

• Beta-1Heart stimulation

• Beta-2Vasodilation and bronchodilation

Drug Effects on Receptors

Drugs can have two types of effects on receptors.

– Stimulating, causing a reaction

– Blocking, preventing a reaction• Dopamine blocking• Anticholinergics

Anticholinergic Side Effects

• Decreased GI motility

• Decreased sweating

• Decreased urination

• Dilated pupils

• Dry eyes

• Dry mouth

Anesthesia

In the “old days” the following were used for anesthesia.

Anesthesia

In the “old days” the following were used for anesthesia.

– Alcohol

– Drugs– Ice for numbing– Blow to the head– Strangulation

Anesthesia

Now, anesthesia is designed to focus on specific systems, such as

Anesthesia

Now, anesthesia is designed to focus on specific systems, such as

• Nervous system • Skeletal system

• Respiratory system • GI system• Endocrine system • Hepatic system• Cardiovascular system

Anesthesia

Goals of Balanced Anesthesia

– Amnesia

Anesthesia

Goals of Balanced Anesthesia– Amnesia

– Adequate Muscle Relaxation

Anesthesia



– Adequate Ventilation

Anesthesia



– Adequate Ventilation

– Pain Control

Types of Anesthesia

• General

• Local

Types of Anesthesia

•General• Local

Discussion

What are some of the indicators used to assess general anesthesia?

Discussion

What are some of the indicators used to access general anesthesia?

Answer: Blood pressure, hypervolemia, oxygen level, pulse, respiratory rate, tissue perfusion, urinary output

General Anesthesia

Preanesthetic Medications– Control sedation– Reduce postoperative pain– Provide amnesia– Decrease anxiety

General Anesthesia

Malignant Hyperthermia– Side effect of anesthesia

• Fever of 110°F or more• Life threatening

– Treatment: dantrolene (Dantrium)

Always check expiration date.

Warning!

Inhalant Anesthetics

• desflurane (Suprane)

• enflurane (Ethrane)

• halothane

• isoflurane (Forane)

• nitrous oxide

Drug List

Inhalant Anesthesia Side Effects

• Causes reduction in blood pressure

• May cause nausea and vomiting

nitrous oxide

• Causes analgesia only; no amnesia or relaxation

• May be given alone or may be given with more powerful anesthetics to hasten the uptake of the other agent(s)

• Commonly used for dental procedures

• Rapidly eliminated

desflurane (Suprane)

• Has rapid onset and recovery

• Often used in ambulatory surgery

General Anesthesia

• Often dispensed by IV drip

• Very lipid soluble

Injectable Anesthetics

• etomidate (Amidate)• fentanyl (Duragesic, Sublimaze)• fentanyl-droperidol• ketamine (Ketalar)• morphine• propofol (Diprivan)• sufentanil (Sufenta)

Drug List

Injectable Anesthetics

Barbituates– methohexital (Brevital)– thiopental (Pentothal)

Benzodiazepines– diazepam (Valium)– lorazepam (Ativan)– midazolam (Versed)

Drug List

propofol (Diprivan)

• Used for maintenance of anesthesia, sedation, or treatment of agitation

• Has antiemetic properties– Drowsiness– Respiratory depression– Motor restlessness

– Increased blood pressure

Injectable AnesthesiaDispensing Issues

Diprivan (anesthetic) and Diflucan (antifungal) may be confused.

This mix-up could be life-threatening.

Warning!

fentanyl

• Dosage Forms– IV (Sublimaze)– patch (Duragesic)– lozenge (Actiq) for children

• Used extensively for open-heart surgery due to lack of cardiac depression

Benzodiazepines

• Used for induction, short procedures, and dental procedures

• Useful in controlling and preventing seizures induced by local anesthetics

• midozolam (Versed) – fastest onset of action– greatest potency– most rapid elimination

Antagonist Agents

Antagonist agents reverse benzodiazepine and narcotic overdose.

Antagonist Agents

• flumazenil (Romazicon)

• nalmefene (Revex)

• naloxone (Narcan)

Drug List

flumazenil (Romazicon)

• Antagonizes benzodiazepines by competing for receptor site

• Used for complete or partial reversal

naloxone (Narcan)

• Competes for opiate receptor sites

• Has a shorter duration of action than narcotics, so it must be given repeatedly

Neuromuscular Blocking Agents

• Causes immediate skeletal muscle relaxation. – Short Duration

– Intermediate Duration– Extended Duration

• Used to facilitate endotracheal intubation. – Allows for easier insertion of endotracheal

tube.– Keeps airway open.

Neuromuscular Blocking Agents

• atracurium (Tracrium)• cisatracurium (Nimbex)• mivacurium (Mivacron)• pancuronium• rocuronium (Zemuron)• succinylcholine (Quelicin)• vecuronium (Norcuron)

Drug List

Neuromuscular Blocking AgentsDispensing Issues

• Very expensive

• Be conscious of storage requirements

• Store away from look-alike and drugs

Warning!

succinylcholine (Quelicin)

• Often called “sux.”

• Only depolarizing agent. All others work as competitive antagonists to ACh receptors.

• Persistent depolarization at motor endplate.

• Causes sustained, brief period of flaccid skeletal muscle paralysis.

Reversal of Neuromuscular Blocking Agents

• Increases the action of acetylcholine by inhibiting acetylcholinesterase

• Used for reversal of nonpolarizing agents

Anticholinesterase Agents

• edrophonium (Enlon)

• neostigmine (Prostigmin)

• pyridostigmine (Mestinon)

Drug List

Types of Anesthesia

• General

•Local

Local Anesthesia

Relieves pain without altering alertness or mental function.

Local Anesthesia

Variety of Dosage Forms– Topical– Superficial injection (infiltration)

– Nerve block– IV– Epidural– Spinal

Discussion

Local anesthetics are classified by their chemistry into two classes.

What are they?

Discussion

Local anesthetics are classified by their chemistry into two classes. What are they?

Answer – Esters– Amides

Local Anesthesia

Esters– Short acting– Metabolized in the plasma and tissue fluids– Excreted in urine

Local Anesthesia

Amides– Longer acting– Metabolized by liver enzymes– Excreted in urine

Local Anesthesia

Esters• benzocaine (Americaine)• chloroprocaine (Nesacaine)• dyclonine (Cēpacol Maximum Strength)• procaine (Novocain)• tetracaine (Cēpacol Viractin, Pontocaine)

Drug List

Local Anesthesia

Amides• bupivacaine (Marcaine)• levobupivacaine (Chirocaine)• lidocaine (L-M-X, Solarcaine, Xylocaine)• lidocaine-epinephrine (Xylocaine w/ Epinephrine)• lidocaine-prilocaine (EMLA)• mepivacaine (Carbocaine)

Drug List

Discussion

What functions are lost with local anesthetics?

Discussion

What functions are lost with local anesthetics?

Answer– Pain perception– Temperature– Touch sensation– Proprioception– Skeletal muscle tone

Discussion

Under what conditions would a local anesthetic be used over a general anesthetic?

Discussion

Under what conditions would a local anesthetic be used over a general anesthetic?

Answer: It is chosen when a well-defined area of the body is targeted.

Pain Management

What is pain? – A protective mechanism to warn of damage or

the presence of disease

– Part of the normal healing process

Managing pain can be a challenge.

Discussion

What are the classifications of pain?

Discussion

What are the classifications of pain?

Answer – Acute– Chronic

• Nonmalignant• Malignant

Pain Management

Acute Pain

• Associated with trauma or surgery

• Easier to manage by treating the cause

• Has a beginning and an end

Pain Management

Chronic Pain• No end to the pain• Patients may have a sense of helplessness and

hopelessness• Affects different aspects of life

– Physical– Psychological– Social– Spiritual

Pain Management

Chronic Nonmalignant Pain

• Cause may be diagnosed or undiagnosed

• Pain lasts for more than 3 months

• Patients may have signs and symptoms of depression

Pain Management

Chronic Malignant Pain

• Accompanies malignant disease

• Often increases in severity with disease progression

Major Sources of PainSource Area

InvolvedCharacteristics Treatment

Somatic body framework

throbbing, stabbing

narcotics, NSAIDS

Visceral kidneys, intestines, liver

aching, throbbing, sharp, crampy

narcotics, NSAIDS

Neuropathic Nerves burning, numbing, tingling

antidepressants, anticonvulsants

Sympathetically Mediated

overactive sympathetic system

no pain should be felt

nerve blockers

Pain Management

Narcotic

• Pain-modulating chemical derived from opium or is synthetically produced

• Also called opioid

• Causes insensibility or stupor

• Mainly effects on CNS and GI tract

• Lesser effects on peripheral tissues

Pain Management

Natural Opioids• Endorphins, enkephalins, and dynorphins• Produced by the brain in response to pain

stimuli• When receptors are activated

– causes decreased nerve transmission– sensation of pain is diminished

• Opioids bind to these same receptors

Discussion

What are the three effects of narcotics?

Discussion

What are the three effects of narcotics?

Answer – Analgesia– Sedation– Euphoria and Dysphoria

Pain Management

Effects of Narcotics

• AnalgesiaReduce pain from most sources

Pain Management

Effects of Narcotics

• AnalgesiaReduce pain from most sources

• SedationDecrease anxiety and cause drowsiness

Pain Management

Effects of Narcotics • Analgesia

Reduce pain from most sources

• SedationDecrease anxiety and cause drowsiness

• Euphoria and Dysphoria– Can cause feelings of well-being and disquiet or

restlessness– Potential for tolerance and dependence

Pain Management

Patient-Controlled Analgesia Pump – Patient controls (within limits) when and how

often medication is administered

– Allows for better pain control

Pain Management

Analgesic Ladder

1. Onset of mild to moderate painAdminister acetaminophen (APAP) or an NSAID

Pain Management

Analgesic Ladder

1. Onset of mild to moderate painAdminister acetaminophen (APAP) or an NSAID

2. Adequate relief is not achieved in Step 1Administer NSAID plus a “weak” opioid (codeine)

Pain Management

Analgesic Ladder 1. Onset of mild to moderate pain

Administer acetaminophen (APAP) or an NSAID

2. Adequate relief is not achieved in Step 1Administer NSAID plus a “weak” opioid (codeine)

3. Adequate relief is not achieved in Step 2Administer a strong opioid (morphine)

Pain Management

Chronic opioid therapy has a low risk of addiction when used appropriately.

Discussion

What is the difference between addiction and dependence?

Pain Management

• DependencePhysical and emotional reliance on a drug

• AddictionCompulsive disorder

Pain Management

Symptoms of Addiction• Preoccupation with drugs• Refusal of medication tapers• Strong preference for a specific opioid• Decrease in ability to function• Medication is typically not taken as prescribed• Have a tendency to visit many different doctors

and pharmacies in order to get the drug(s)

Narcotic Dispensing Issues

Pharmacy technicians have a legal and moral responsibility to alert pharmacist of suspected abuse and addiction.

Warning!

Pain Management

Patients are more successful overcoming addiction if withdrawal symptoms are handled appropriately.

Addiction Treatment

• buprenorphine (Buprenex, Subutex)

• buprenorphine-naloxone (Suboxone)

• methadone (Dolophine)

Drug List

methadone (Dolophine)

• Uses – Detoxification – Maintenance of narcotic addiction

• Dispensed in clinics or in hospitals

• Binds to opiate receptors without giving a euphoric feeling

Discussion

What are the pros and cons of methadone clinics?

Pain Management

Combinations of narcotics and nonnarcotics is common.

– Enhances relief

– Facilitates use of lower doses– Decreases side effects

Pain Management

Combinations can be dangerous if the ASA or APAP dose is overlooked.

Technicians should be aware of this risk and assess each prescription for possible toxic doses.

Warning!

Narcotic Analgesics

Varying dose requirements due to– Severity of pain– Individual response to pain– Patient’s age and weight– Presence of concomitant disease

Narcotic Analgesics

• Many different dosage forms and strengths are available.

• Goal: Patient comfort

• Key to reaching goal: Constant reassessment

• Side effects should be anticipated and minimized for patient comfort

Narcotic Analgesic Side Effects

– Mental confusion– Reduced alertness– Nausea/vomiting

– Dry mouth– Constipation– Inflammatory process

– Bronchial constriction

Narcotic Analgesics

• APAP-codeine (Tylenol With Codeine)• hydrocodone-APAP (Lortab, Vicodin)• hydromorphone (Dilaudid)

• meperidine (Demerol)• morphine (MS Contin)• oxycodone (OxyContin)

Drug List

Narcotic Analgesics

• oxycodone-APAP (Endocet, Percocet, Tylox)• oxycodone-ASA (Endodan, Percodan)• oxymorphone (Numorphan)• pentazocine (Talwin)• pentazocine-naloxone (Talwin NX)• propoxyphene (Darvon)• propoxyphene-APAP (Darvocet-N 100)

Drug List

Narcotic AnalgesicDispensing Issues

• Be careful of multiple strengths.

• Lortab and Lorabid can be confused. Pay attention to dosing schedule.

• Morphine sulfate and magnesium sulfate are often confused.

Warning!

Migraine Headaches

Migraine– Severe, throbbing, vascular

headache– Recurrent unilateral head pain– Combined with neurologic and

GI disturbances

Migraine Headaches

• 90% of migraine sufferers report nausea.

• Sensitivity to light, sound, and stimulation are also common.

Migraine Headaches

Components of classic migraine (all five not experienced by every migraine sufferer):

– Prodrome

– Aura– Headache– Headache relief– Postdrome

Migraine Headaches

ProdromeSymptom indicating the onset

Migraine Headaches

AuraSubjective sensation or motor phenomenon that precedes and marks the onset of a migraine attack

• Flashing lights• Shimmering heat waves• Bright lights• Dark holes in visual fields• Blurred or cloudy vision• Transient loss of vision

Migraine Headaches

Headache and Headache ReliefHeadache generally dissipates in six hours, but may last one to two days

Migraine Headaches

PostdromeKnowing the headache is gone

Migraine Headaches

Serotonin appears to be involved in cause.– Decreased levels = excessive vasodilation in

cranial arteries = headache.

– By stimulating serotonin receptors, vasoconstriction will occur thereby alleviating the migraine.

Migraine Headaches

Causative Factors

• Diet

• Stress

• Depression

• Sleep habits

• Certain medications

• Hormonal fluctuations

• Atmospheric changes

• Environmental irritants

Migraine Headaches

Initial Treatment

• Identifying and eliminating triggersEx: red wine, caffeine, certain foods, bright lights

• If attacks are still frequent, drug therapy may be indicated

Discussion

Migraine drug therapy can be divided into two classes. What are they?

Discussion

Migraine therapy can be divided into two drug classes. What are they?

Answer – Prophylactic Therapy– Abortive Therapy

Migraine Headaches

• Prophylactic TherapyAttempts to prevent or reduce recurrence

• Abortive Therapy

Migraine Headaches

• Prophylactic TherapyAttempts to prevent or reduce recurrence

• Abortive Therapy– Treats acute migraine attacks– Taken after headache occurs, at first sign of a

headache

Migraine Headaches

• Prophylactic Therapy– Anticonvulsants– Beta blockers– Calcium channel

blockers– Estrogen– Feverfew– NASAIDs– SSRIs– Tricyclic

antidepressants

• Abortive Therapy– Simple analgesics

– NSAIDs

– Ergotamine-containing medications

– Other drugs

Migraine Headaches

Triptans—Selective 5-HT Receptor Agonists• almotriptan (Axert)• eletriptan (Relpax)• frovatriptan (Frova)• naratriptan (Amerge)• rizatriptan (Maxalt, Maxalt-MLT)• sumatriptan (Imitrex)• zolmitriptan (Zomig)

Drug List

sumatriptan (Imitrex)

• Binds to serotonin receptors causing vasoconstriction of blood vessels in the dura

• Use at first sign of headache

• Available in injection, nasal spray, and tablet

rizatriptan (Maxalt-MLT)

• Sublingual tablet, quickly absorbed

• Has most rapid onset of action of all oral migraine therapies

• May receive relief after 30 minutes

• Maxalt is not absorbed as quickly as Maxalt-MLT

Migraine Headaches

Ergot Preparations

• dihydroergotamine (D.H.E. 45, Migranal)

• ergotamine (Ergomar)

• ergotamine-caffeine (Cafergot)

Drug List

Migraine Headaches

Antiemetic Agents

• chlorpromazine (Thorazine)

• metoclopramide (Reglan)

• prochlorperazine (Compazine)

Drug List

metoclopramide (Reglan)

• Reduces nausea and vomiting

• Enhances absorption of other antimigraine products

• Metoclopramide (Reglan) and aspirin have been prescribed together instead of using sumatriptan (Imitrex)

Migraine Headaches

Opiod Analgesic

• butorphanol (Stadol, Stadol NS)

Beta Blocker

• propranolol (Inderal)

Drug List

butorphanol (Stadol, Stadol NS)

• Nasal spray is used more commonly than injection

• Has analgesic properties for moderate-to-severe pain

• Can be addictive and abused

• A controlled substance in some states

Migraine Headaches

Other• butalbital-APAP-caffeine (Fioricet)• butalbital-ASA-caffeine (Fiorinal)• isometheptene-dichloralphenazone-APAP

(Midrin)• tramadol (Ultram)

Drug List

Migraine AgentsDispensing Issues

Tramadol and Toradol could be confused. Be sure of which drug is being prescribed.

Warning!

tramadol (Ultram)

• High success rate when given with NSAIDs (ibuprofen)

• Has slow onset of action

• Is not a controlled substance, but has shown potential for addiction

isometheptene-dichloralphenazine-acetaminophen (Midrin)

• Has fewer side effects than ergotamines, but may be less effective

• Combination of analgesic, sedative, and vasoconstrictor

Discussion

What are some of the issues facing migraine sufferers and the medication that is used?

Discussion

What are some of the issues facing migraine sufferers and the medication that is used?

Answer– N/V

– 0.5-2 hour onset of action– side effects of medications