This document discusses central nervous system (CNS) drugs. It classifies CNS drugs into three main categories: CNS depressants, CNS stimulants, and CNS modifiers (tranquilizers). CNS depressants are further divided into non-selective depressants like hypnotics and sedatives, and selective depressants like analgesics and anti-convulsants. CNS stimulants include cerebral stimulants, respiratory stimulants, analeptics, and psychomotor stimulants. CNS modifiers include major and minor tranquilizers used to treat mental disorders. The document also discusses the classification of CNS drugs based on their chemical structure, which includes barbiturates,

1. DEPARTMENT : CHEMISTRY
SUBJECT : DRUGS & DYES
TOPIC : CENTRAL NERVOUS SYSTEM
DRUGS Presented by:
Hariom Kew
kWatt
Education and Learning

2. CNS Drugs
 The drugs which act on the CNS(Central Nervous System) are
known as CNS drugs
 The CNS consists of cerebrum, cerebellum, medulla and the
spinal cord.
A. CNS depressants
 The drugs which have a depressant action on the CNS
 Non selective depressants: which produce a generalised depressant
action on the CNS. Eg. Hypnotic and sedative, central muscle
relaxants
 Selective depressants: it selectively depress certain region or portion
of the CNS.
 They include tranquillizers, Analgesics and anti-convalsants
B. CNS stimulants
 the drugs which stimulate and reactivate CNS
 used for variety of purposes like treatment of depressive state,
maintenance of wakefulness restoration of respiration and blood
and restoration of normal reflexes.
C. CNS modifiers(Tranquillizers)
 used in treatment of mental disorders.
 they produce improvement in the mood and behaviour of the patient

3. •Non selective CNS depressants
•Selective depressants
CNS
depressants
•Cerebral Stimulant
•Respiratory Stimulant
•Analeptics(restorative)
•Psychomotor stimulant
CNS
stimulants
•Major Tranquillizers
•Minor Tranquillizers
CNS
modifiers
CLASSIFICATION OF CNS
DRUGS BASED ON
PHARMACOLOGICAL ACTIVITY

4. CONCEPT
OF
HYPNOSIS
AND
SEDATION
AND
ANESTHESI
A
o The sedation and hypnosis are closely related
terms
o A hypnotic is a drug which produces sleep
resembling natural sleep
o A sedative is a drug which produces mild
depression and calms anxiety causing
drowsiness or impaired performance
o A sedative when given in large dosage act as a
hypnotic.
o A hypnotic when given in small dosage act as
a sedative.
o Hypnotics and sedatives are mainly used for
the treatment of insomnia.
o General anaesthetics are depressant drugs
that produce partial or total loss of sense of

5. CLASSIFICATION OF CNS
DRUGS BASED ON
CHEMICAL STRUCTURE
1. Barbiturates
o They are derivatives of barbituric acid having
substitution at position 5th or 1st.
o Barbiturates dominated the sedative hypnotic
field
o Side effect: It is habit forming and gives rise to
drowsiness.
2. Hydantoins
o They are cyclic mono acyl ureas and are weaker
organic acids than barbiturates
o Useful for treatment of all types of epilepsy,
cardiac arrhythimia, etc
o Side effect: dizziness, itching, skin rashes
3. Oxazolidine diones
1. N-H group at position 1 of a hydantoin nucleus
is replaced with an oxygen atom

6. 4. Pyrrolidones
o These are pyrrolidone substituted
derivatives of amides
o Used to create a favourable effect on
mind in case of Alzheimer's disease and
associated dementia
o Side effect: causes gastrointestinal
disturbance
5. Benzodiazepines
o The aromatic ring is fused to the seven
membered heterocyclic ring with an aryl
group substituted at 5 position
o It have depressant action on the CNS, anti
anxiety agent, sleep inducer
o Side effect: drowsiness and lethargy
6. Piperidines
1. They are piperidyl derivatives of esters of
phenyl acetic acid.
2. Methyl phenidate is mild CNS stimulant

7. 7. Phenothiazines
o These drugs have a heterocyclic ring system
called phenothiazine having substitution in 2
and 10 position.
o Chloropromazine produces psychomotor
slowing, emotional quietening and decrease
of anxiety without affecting wakefulness
o It is also used in minor psychatric disorders
or neurosis
8. Phenyl propyl amines
o Used as antidepressants, treatment of
obesity
o Also used in treatment of narcolepsy,
alcoholism, with barbiturates they are
used in treatment of epilepsy
o Side effect: prolonged use results in a
psychotic state of suspicion and

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