1.
Central
Nervous
System
Agents
Ma. Tosca Cybil A. Torres, RN,
MAN

2.
CNS
Stimulants

3.
CNS stimulants are drugs
which increase the muscular
(motor) and the mental
(sensory) activities
 Their effects vary from the
increase in the alertness and
wakefulness (as with
caffeine) TO the production
of convulsion ( as with
strychnine) or death due to
over stimulation

4.
Behavioral Manifestations of CNS
Stimulation
• mild elevation in alertness, decrease in
drowsiness and lessening of fatigue
(Analeptic Effect)
• increased nervousness and anxiety -
convulsions.

5.
Molecular Basis of CNS
Stimulation
Imbalance between inhibitory and excitatory
processes as in the brain. This
hyperexcitability of neurons results from:
• potentiation or enhancement of excitatory
neurotransmission(e.g. amphetamine)
• depression or antagonism of inhibitory
transmission (e.g. Strychnine)
• presynaptic control of neurotransmitter
release (e.g. picrotoxin)

6.
Classification of CNS
Stimulants
• Analeptic Stimulants
– Respiratory Stimulants
– Convulsants
• Psychomotor Stimulant
– Sympathomimetics or
Adrenergic CNS Stimulants
• Methylxanthines

7.
Analeptic Stimulants
• diverse chemical class of agents
• majority can be absorbed orally
• have a short duration of action -
primary expression of
pharmacological effect is
convulsions (tonic-clonic)
uncoordinated
• pharmacological effect is
terminated through hepatic
metabolism
• Possible Common Mechanism of
Action -ability to alter movement of
chloride ions across neuronal
membranes

8.
Respiratory CNS
Stimulants
• Doxapram - used to counteract postanesthetic
respiratory depression and for acute
hypercapnia in chronic pulmonary disease.
– Used with caution with neonatal apnea
– Administered IV
– Onset of action: within 20-40 secs
– SE: (overdose)
• Hypertension
• Tachycardia
• Trembling
• convulsions

9.
Headaches: Migraine and
Cluster Migraine headaches-
characterized by a unilateral
throbbing head
pain, accompanied by N/V
and photophobia
Cluster headaches-
characterized by severe
unilateral nonthrobbing pain
usually located around the
eye. Usually not associated
with N/V

10.
Preventive Treatment for
migraine
1. Beta adrenergic blockers
2. Anticonvulsants- Valproic
acid (Depakote)
3. Tricyclic antidepressants-
amitriptyline (Elavil)

11.
Treatment or Cessation of
Attacks
• Ergotamine tartrate
– Nonspecific serotonin agonist and
vasoconstrictor
– Should be taken early during a
migraine attack
– May cause N and V

12.
• Triptans
– The most common recently developed group of
drugs for tx of migraines and cluster headches
– Prototype: sumatriptan(Imitrex)
• Selective serotonin receptor agonist with a short
duration of action
• Considered more effective than ergotamine
• MOA: causes vasoconstriction of cranial carotid
arteries to relieve migraine attacks
• SE: dizziness, fainting, tingling, numbness, warm
sensation, drowsiness
• AR: hypotension, heart block, angina, MI, cardiac
arrest

13.
• Amphetamines
– Stimulates the release of
norepinephrine and dopamine from the
brain and SNS.
– Can cause euphoria and alertness

14.
CHARACTERISTICS
• all compounds are absorbed well orally
• large portion of untransformed amphetamine is
excreted unchanged in the urine.
Consequently, acidifying the urine with ammonium
chloride hastens its clearance, and thus reduces
its reabsorption in the renal tubules.
• Overdose: hyperreflexia, tremors, convulsions and
irritability
• CV problems: increased heart rate, increased
BP, palpitations and cardiac dysrythmias

15.
• Therapeutic Uses:
– Narcolepsy
• Characterized by falling asleep during waking hours,
such as driving a car or talking with someone. Sleep
paralysis, a condition that is normal during sleep
usually accompanies narcolepsy which affects the
voluntary muscles making the person unable to move
and collapse

16.
• Therapeutic uses:
– Attention Deficit/Hyperactivity Disorder
• May be caused by disregulation of
serotonin, norepinephrine, and dopamine.
• Occurs primarily in children, usually before
the age 7, but may continue through
teenage years.
• Characteristics involved include
inattentiveness, poor coordination, inability
to concentrate, restlessness, hyperactivity
(excessive and purposeless activity),
inability to complete tasks, and impulsivity.

17.
Pharmacological Actions
• The primary effects of an oral dose are
wakefulness, alertness, decrease fatigue; mood
elevation, increased ability to concentrate; an
increase in motor and speech activity.
Amphetamines also diminish the awareness of
fatigue; person may push exertion to the point of
severe damage or even death.

18.
• Stimulate the respiratory center,
especially when respiration is
depressed by centrally acting drugs,
(barbiturates and alcohol).
• Amphetamine can reverse the marked
sedation and behavioral retardation
resulting from reserpine-like drug.
• Depresses appetite by their action on
the lateral hypothalamus rather than
an effect on metabolic rate.

19.
Mechanisms of Action
• Releases monoamines at synapses
in the brain and spinal cord.
• Inhibits neuronal uptake of
monoamine
• Antagonist at certain
adrenoreceptors
• May inhibit monoamine oxidase.

20.
Adverse Effects
• CNS:
Euphoria, dizziness, tremor, irritability
, insomnia, Convulsion (at higher
doses), hyperthermia and coma
• C.V. Cardiac stimulation leads to
headache, palpitations, cardiac
arrhythmias, anginal pain
• Other: Weight loss, Psychotic
Reaction which are often
misdiagnosed as schizophrenia.
• Addiction - including psychic
dependence, tolerance and physical
dependence.

21.
• Drug Interactions:
– Tricyclic antidepressant
– Antihypertensive Agents
– Foods high in tyramine content

22.
• Amphetamine-like Drugs or ADHD and
Narcolepsy
– Given to increase a child’s attention span and
cognitive performance and decrease
impulsiveness, hyperactivity and restlessness
Prototype:
– Methylphenidate(Ritalin)
– Dexmethypendate (Focalin)
– Pemoline (Cylert)
– Modafinil(Provigil)- drug for nacolepsy which
increases the amount of time that clients feel
awake

23.
Side Effects:
anorexia, vomiting,
diarrhea, insomnia,
dizziness, nervousness,
restlessness, irritability
Adverse reaction:
tachycardia, growth
suppression,
palpitations, transient
loss of weight in
children, and increased
hyperactivity

24.
Nursing
considerations:
• Monitor V/S. report
irregularities
• Record height, weight, and
growth of children
• Observe for withdrawal
symptoms (N and V,
weakness, and headache)
• Monitor for side effects

25.
Nursing considerations
• Instruct client to take drug with meals
• Avoid alcohol consumption
• Encourage use of sugarless gum to relieve
dryness of mouth
• Monitor weight twice a week
• Advise not to drive and use hazardous
equipments when experiencing palpitation,
nervousness, tremors

26.
Nursing
considerations
• Instruct client not to discontinue the drug
abruptly
• Advise not to eat foods with caffeine
• Instruct to eat nutritious food because
drug may cause anorexic effect
• Teach to report drug side effects such as
tachycardia and palpitations

27.
CNS
Depressa
nts

28.
CNS Depressants: Classification
They are classified
according to their
pharmacological action
into:
1- Sedative – hypnotics
2- Anaesthetics

29.
e
-
Hypnoti
cs

30.
• Sedation
–Mildest form of CNS depression
–Diminishes physical and mental
responses at lower dosages of
certain CNS depressants but
does not affect consciousness

31.
ep
Definition:
Physiological depression of consciousness
Sleep cycle:
Starts with latency period → NREM → REM →
cycles of NREM alternate with REM (about 4
cycles)
NREM REM
- Non rapid eye movement - Rapid eye movement
- Lasts for 90 min. - Lasts for 20 min.
- Thinking - Dreaming

32.
I- Sedative - Hypnotics
Definitions
Sedatives:
Drugs which calm the patient & cause sedation and in large
doses cause sleep
Hypnotics:
Drugs which induce sleep that resembles the natural sleep
Ex. Barbiturates

33.
Sedative Hypnotics
Mechanism of Action
• The GABA receptor is a pentameric structure that
forms a Cl- channel.
• The receptor complex includes distinct binding
sites for benzodiazepines, barbiturates and
GABA-like substances.
• GABA transmission exerts an inhibitory effect on
norepinephrine (NE), dopamine (DA), serotonin
(5-HT), and acetylcholine (ACh) pathways.

34.
Sedative – hypnotics:
Classification
Sedative-hypnotics
Barbiturates Non-barbiturates
1-Long acting (12-24 hr)
Ex. Phenobarbital
Benzodiazepines Non- benzodiazepine
2-Intermediate acting (8-12hr)
Ex. Amobarbital
3-Short acting (4-8 hr)
Ex. Pentobarbital
4-Ultrashort acting (0.5-1hr)
Ex. Thiopental

35.
Barbiturates
MOA:
They have GABA like action → ↑ opening time
of chloride channels → ↑conductance of
chloride ions → hyperpolarization
Classification:
1-Long-acting
2-Intermediate-acting
3-Short acting
4-Ultrashort acting

36.
• Barbiturates
– Prototype:
• Short acting: pentobarbital
sodium(Nembutal sodium) – for
sedation, sleep, or preanesthetic
• Intermediate acting: amobarbital
sodium(Amytal sodium)- sedative
and short term hypnotic, to control
acute convulsive episodes, and for
insomia
• Long acting: phenobarbital and
mephobarbital-used to control
seizures
• Ultrashort-acting: thiopental
sodium- used as a general
anesthetic

37.
Nursing Responsibilities:
• Recognize that continued use of
barbiturate might result in drug abuse
• Monitor V/S, esp. RR and BP
• Raise side rails
• Check for rashes
• Administer phenobarbital IV at a rate of
less than 50mg/min. do not mix with other
medications. If to be given IM, use large
muscle such as the gluteus max

38.
Client teaching
• Teach client the use on non pharmacological
ways to induce sleep----enjoying a warm bath,
listening to music, drinking warm fluids, and
avoiding drinks with caffeine 6hrs before
bedtime
• Instruct to avoid alcohol and antidepressants,
antipsychotics, and narcotic drugs----
respiratory depression
• Avoid taking herbs
• Advise not to drive or operate a machinery
• Instruct to take 30mins before bedtime

39.
Benzodiazepines
• Can suppress stage 4 of NREM sleep, which may result
in vivid dreams or nightmares and can delay REM sleep.
• Effective for sleep disorders for several weeks longer
than other sedative-hypnotics but should not be longer
than 3-4 weeks as a hypnotic to prevent REM rebound
Prototype:
Alprazolam(Xanax)- for alleviating anxiety that may cause
sleeplessness
Estazolam(ProSom)- for treatment of insomia. Decreases
the frequency of nocturnal wakefulness
Lorazepam(Ativan)-used as a pre operative sedative and
to reduce anxiety

40.
Nonbenzodiazepines
 used for short term treatment of insomia
 Well absorbed PO, onset 7-27 minutes
MOA: depression of the CNS, neurotransmitter
inhibition
Prototype:
zolpidem(Ambien)
S/E:
drowsiness, lethargy, hangover, irritability, dizzine
ss, anxiety
Adverse reactions:
tolerance, physiologic dependence

41.
• Nursing responsibilities:
– Monitor V/S. check for respiratory depression
– Raise side rails
– Observe for side effects (hangover, light-
headedness, dizziness, or confusion)
– Teach non pharmacological ways to induce
sleep
– Suggest to urinate before taking sedative
hypnotics to prevent sleep disruption
– Instruct to avoid alcohol and antidepressants,
antipsychotics, and narcotic drugs----
respiratory depression

42.
Anaesthetics
Definition:
Drugs which cause unconsciousness &
generalized loss of pain sensation, thus
allow surgical procedures to be carried out
Classified as general and local
Ex. thiopental (IV) , halothane (inhalation)
MOA:
Interfering with propagation of nerve impulses
by interfering with electrolytes movement
through the cell membrane

43.
General anesthesia
• Is a reversible loss of consciousness induced by
inhibiting neuronal impulses in several areas of the
central nervous system
• General anesthetics are agents that block the pain
stimulus at the cortex
Produces a state of the ff:
 Analgesia
 Amnesia
 Unconsciousness characterized by loss of reflexes
and muscle tone

44.
Local anesthesia
• Injection of a solution containing anesthetic
into the tissues at the planned incision site.
• Briefly disrupts sensory nerve impulse
transmission form a specific body area or
region.
Types of Local anesthesia
1. Topical anesthesia – topical agents are
applied directly to the area of skin or mucous
membrane surfaced to be anesthetized
2. Local infiltration – is the injection of an
anesthetic agent directly into the tissue
around an incision, wound, or lesion.

45.
Purposes of Anesthesia
• To produce muscle relaxation
• To produce analgesia
• To produce artificial sleep or to cause loss
of consciousness
• To block transmission of nerve impulses
• To suppress reflexes

46.
• Nursing responsibilities:
– Monitor client’s postoperative state of
sensorium.
– Check preoperative and postoperative urine
output
– Record V/S after induction of anesthesia----
may result to hypotension and respiratory
distress
– Administer an analgesic or a narcotic-
analgesic with caution until client fully
recovers from the anesthetic