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6. Pharmacology of Central Nervous System
The autonomic nervous system is “autonomic” because it
is not under the influence of volition or will, by contrast
the somatic fibers are often controlled by the will. The
sympathetic and parasympathetic system are the two main
divisions of autonomic nervous system.
The sympathetic system is also called “thoracolumbar
outflow”. The “preganglionic fibers”, originate from all
(i.e. from all the twelve) thoracic segments plus the two
or three upper lumbar segments of the spinal cord relay
in the “sympathetic ganglia”. From the sympathetic
ganglia, “postganglionic fibers” arise and terminate in
their target cells. The parasympathetic system is also called
“craniosacral outflow” because the nerves arise:
i. Either from the brain and conveyed via IIIrd, VIIth,
IXth and Xth cranial nerves.
ii. Or from the IInd, IIIrd and IVth segments of sacral
segments of spinal cord.
Sedative hypnotic (Fig. 6.1)
Sedatives are agents which reduces anxiety and calms the
recipients without inducing sleep, but they can induce
drowsiness, i.e. benzodiazepines.
Hypnotics are drugs which produce sleep that resembles
to normal sleep. Hypnotic effect involves more pronounced
depression of CNS than sedation, and this can be achieved
by simply increasing the dose of sedatives.
Classification
Benzodiazepines
BDZs contain a benzene ring and a 7 membered ring. In
addition, they also contain a substituent ring (ring C).
Most, BDZs are absorbed from the GIT completely. After
absorption, they traverse the body as follows: Available in
blood then enter into brain, then again back to blood and
an equilibrium is established.
1. Hypnotics: Diazepam, nitrogen palm
2. Anti-anxiety: Diazepam, alprazolam
3. Anticonvulsant Diazepam clonazepam clobazam
4. Newer non benzodiazeine hypnotic: Zopiclone.
5. Miscellaneous: Chloral hydrate, para aldehyde.
Clinical uses
They can be used as—
1. Anxiolytic—it is often helpful in primary anxieties, e.g.
panic disorder and generalized anxiety.
2. Hypnotics—as hypnotics flurazepam, temazepam and
triazolam are especially popular.
3. Anticonvulsant—in emergency control of status
epilepticus IV diazepam may be given.
4. As muscle relaxant—in muscle spasm due to muscle
strain, diazepam can be used.
5. In alcohol withdrawal—diazepam can be used.
Fig. 6.1: Classication of sedative-hypnotics
BARBITURATES (BARBT)
Barbiturates are the derivatives of barbituric acid.
Classification with Basis
On the basis of duration of action
a. Long-acting—for example, phenobarbitone,
mephobarbitone
b. Intermediate acting—for example, amylobarbitone,
butobarbitone
c. Short-acting—for example, pentobarbitone,
quinalbarbitone
d. Ultrashort-acting—for example, thiopental sodium,
methohexital.
On the basis of clinical use
a. Long-acting barbiturates are used as anticonvulsants,
e.g. phenobarbitone.
b. Intermediate and short-acting ones are hypnotic, e.g.
secobarbitone.
c. Ultrashort acting groups are intravenous anesthetics,
e.g. thiopentalsodium.
Barbiturates depress the activity of all brain cells,
they specially depress the reticular activating system
and neural activity in the posterior hypothalamus,
amygdaloid complex and limbic system. In small doses,
they also enhance the effects of GABA (an inhibitory
neurotransmitter).
Section 1 Pharmacology
69
General anaesthesia
General anesthetics are drugs which produce—(1)
analgesia. (2) amnesia (3) reversible loss of consciousness.
(4) adequate muscle relaxation and (5) loss of reflexes in
subject. Their therapeutic indices are low, that is slight
overdose is potentially fatal. They have got no receptors,
they are all nonspecific drugs and hence they have no
antagonist.
Adjunct to Anesthesia
Agents used objectives
1. Benzodiazepines – to relieve anxiety
2. Barbiturates – to produce sedation
3. H1-blockers – to prevent bronchial secretion
4. Antiemetics – to prevent stomach contents into
respiratory tract
5. Opioids – to produce analgesia
6. Atropine – to prevent bradycardia
7. Muscle relaxant – to facilitate intubation.
Preanesthetic medication, basal and balanced anesthesia
STAGES OF ANESTHESIA
When G/A is produced by using ether as the sole agent,
the following four stages are seen which appears one after
another, as if in a procession.
Stage I: stage of analgesia—due to decreased activity of
the cells of SGR (substantia gelatinosa of Rolando) in the
dorsal horn of spinal cord. So there is, interruptions of
sensory transmission in spinothalamic tract, including
nociceptive stimuli.
z
Start from inhalation and last up to loss of consciousness
z
Pain is abolished
z
Patient remain conscious can hear see and feel a dream
like state
z
Reflex and respiration
z
remain normal.
Stage II: Stage of delirium—due to blockade of many
small inhibitory neurons, e.g. Golgi type II cells,
together with a paradoxic facilitation of excitatory
neurotransmitters.
z
From loss of consciousness to beginning of regular
respiration
z
Apparent excitement is seen-patient may shout,
struggle, hold his breath, muscle stone increases, jaw
tightly closed, vomiting, involuntary acceleration,
defecation can occur
z
Heart rate and blood pressure may be increased.
Stage III: Stage of surgical anesthesia—due to progressive
depression of ascending pathway in the reticular
activating system, together with suppression of spinal
reflex activity that contributes to muscle relaxation.
z
Extends from onset of regular respiration to cessation
of spontaneous breathing
z
Loss of corneal reflex and people start dilating
z
Cellular respiration
z
Muscles tone decrease, blood pressure decrease, heart
rate increase
Section 1 Pharmacology
Stage IV—Stage of medullary depression—Due to
depression of neurons of respiratory and vasomotor
70
center of the medulla that is cardiorespiratory center.
z
Cessation of breathing to failure of circulation and
death.
Classification of General Anesthetics
General anesthetics are of two kinds (Fig. 6.2):
1. Inhalation anesthetics
2. Intravenous anesthetics
Fig. 6.2: Types of general anesthetics
COMPLICATIONS
During anaesthesia
Respiration depression and hypercarbia
Cardiac arrhythmia a systole
Fall in blood pressure
Aspiration of gastric contents pneumonia laryngospasm
Delirium convulsion
After anaesthesia
Nausea, vomiting
Persist sedation
Pneumonia
Nerve palsy due to faulty positioning
Liver, kidney damage.
Preanaesthetic medication
Refer to the use of drugs before anaesthesia to make it more
pleasant and save. The aim is to:
It relieves anxiety.
Supplement analgesic action so less than anaesthetic is
need.
Decrease secretion and vagal
stimulation caused by anaesthesia to prevent aspiration.
Antiemetic effect extending to postoperative period to
prevent vomiting during anaesthesia.
To suppress respiratory secretion salivary secretion
gastric secretions.
Preanesthetic drugs
1. Opioids: Morphine, pethidine.
z
Allow anxiety, decrease the dose of aesthetic required.
Disadvantage
z
Decrease respiration
z
Decrease in BP
z
Can precipitate asthma
z
Constipation
z
Vomiting
z
Urinary retention.
2. Antianxiety drug: Benzodiazepine.
3. Sedative hypnotic: Barbiturates, diazepam (provide
-amnesia)
4. Anti-cholinergic
z
Decrease secretion (salivary and bronchial)
z
Preventive vagal bradycardia and hypertension.
z
Prevent laryngo spas have antiemetic effect atropine
or hyoscine or Bella done is used.
5. H2 blockers in prolonged
z
Operation it decreases chances of regurgitation,
prevent stress ulcer postoperatively
6. Antiemetic: Metoclopramide, Domperidone.
Psychopharmacological agents
Antipsychotics, antidepressants, antianxiety agents, antimanics and hallucinogens.
Schizophrenia is a psychosis characterized by a clear
consciousness but a marked thinking disturbance (delusion
and hallucination) and associated with aggressiveness,
agitated behavior (positive schizophrenics) or with
emotional blunting, poor socialization, and cognitive
deficit (negative schizophrenics).
Antidepressants
Depression itself can be subdivided into—(i) endogenous
depression and (ii) reactive depression. In reactive
depression, there is an external cause for depression, e.g.
failure in a critical examination or death of a beloved one
and so forth. In endogenous depression, there is no external
cause, the patient is mentally depressed for nothing and
such cases are the most important cases.
The antidepressant drugs are very effective against
endogenous depression but not so effective against reactive
depression (Fig. 6.4).
Depending on the propensity to cause extrapyramidal
adverse effects the commonly used antipsychotic drugs
can be classed.
Category 1: It includes chlorpromazine, methotrimeprazine, promethazine, thiothixene, risperidone,
chlorprothixene, molindone, and perphenazine and
is characterized by moderate extrapyramidal adverse
effects.
Category 2: Drugs are thioridazine, mesoridazine,
olanzapine, clozapine, sertindole, ziprasidone, and
quetiapine and have fewer extrapyramidal adverse
effects than category 1 and 3 drugs.
Category 3: Drugs are characterized by more pronounced
extrapyramidal adverse effects than category 1
and 2 drugs. This category includes fluphenazine,
prochlorperazine, trifluoperazine, haloperidol,
pimozide, flupenthixol, sulpiride, loxapine. In general,
antipsychotic drugs are more effective in cases of positive
schizophrenics than in patients with negative symptoms.
The antipsychotics can also be used to quieten disturbed
patients with brain damage, mania, toxic delirium or
agitated depression (Fig. 6.3).
Fig. 6.3: Type of antipsychotics
Fig. 6.4: Type of antidepressant drugs
Antiepileptic
Epilepsy are group of disorders of CNS characterized by
paroxysmal cerebral dysarrhythmia, manifested as episode
of scizures, loss of disturbances of consciousness with or
without body movement convulsion.
Group of disorders in which there are recurrent episodes
of altered cerebral function associated with paroxysmal
excessive and hypersynchronus discharge of cerebral
neurons, which may or may not be associated with loss
of consciousness.
TYPES OF SEIZURES (Figs 6.5 and 6.6)
Types
1) Generalised/tonic clonic seizures/major epilepsy or
grand mal-
z
Commonest last for one to two minutes acute
z
In this patient cry unconsciousness tone expansion
of all body muscles clonic jerking prolonged sleep
depression of all CNS functions.
2) Absent seizure or minor epilepsy or petitmal.
z
In this patient have momentary loss of consciousness,
apparently freeze and spares in one direction.
3) Atonic –
z
Patient become unconsciousness with relaxation of
all muscles.
Section 1 Pharmacology
71
Fig. 6.5: Classication of seizures
Fig. 6.6: Drugs used in epilepsy
4) Myoclonic-
z
In this patient have shock like momentary contraction
of a muscles of a limb or whole body.
5) Infantile spasm-
z
It is not a form of epilepsy.
z
Patient have intermittent muscle spasm and
progressive mental orientation.
Classification
1. Barbiturate—phenobarbitone (drug of choice in
pregnancy)
2. Benzodiazepine—diazepam, clonazepam
3. Hydantoin—phenytoin (contraindicated in pregnancy),
epsolin (drug of choice)
4. Aliphatic carboxylic acid—valproic acid
5. Iminostilbene—carbamazepine
6. Miscellaneous—phenacemide, acetazolam.
7. Deoxybarbiturate—primidone.
8. Succinamide—ethosuximide.
9. Newer drugs—lamotrigine, gabapentine.
Phenytoin
It is not a CNS depressant.
Action is abolition of tonic phase of maximal
Seizures, with no effect on prolongation of clonic phase.
It limits spread of seizure.
Activity threshold for conversion is not raised tonicclonic epilepsy is suppressed.
Status epilepticus
It is the continuous clinical manifestation of an epileptic
discharge without intermission recurrent tonic-clonic
Section 1 Pharmacology
convulsion without recovery of consciousness as quickly
as possible to prevent death and permanent brain
72
damage.
Treatment
1. Diazepam 10 milligram IV bolus
2. Phenobarbitone or phenytoin substituted after
conversion is over
3. Para aldehyde (deep intramuscular or per rectum) if I/
V is difficult
4. General anaesthesia if not responding with above drugs
5. General measure maintenance of airway oxygenation
electrolyte balance blood pressure care of
unconsciousness.
z
When seizure
z
actively occurs for more than 30 minutes or two or
more seizure occur without recovery it is labelled
status epilepticus.
z
Recurrent tonic-clonic convulsion without recovery
of consciousness is an emergency permanent brain
damage
Anti-parkinsonism
Parkinsonism is an extrapyramidal motor disorder
characterized by rigidity, trimmer and hypokinesia with
secondary manifestation of defective postural get mask
like face silorrhoea if untreated it progress over the end
stage in which patient is so rigid and he is unable to move
unable to breathe properly and prone to chest infection.
Parkinsonism is a disease of basal ganglia of brain,
characterized by tremor, rigidity and akinesia which
includes—
1. Paralysis agitans
2. Postencephalitic parkinsonism
3. Wilson’s disease
4. Shy-Drager syndrome
5. Mn- intoxication
6. Drug-induced parkinsonism.
Classification
1. Drugs affecting brain dopaminergic system
z
Dopamine precursor—levodopa
z
Dopamine agonist—bromo cremaffinlisuride
z
Peripheral decarboxylase inhibition—carbidopa
z
Facilitate dopamine transmission—amantadine.
2. Drug affecting brain cholinergic system
z
Central anticholinergic—Benzhexol, Biperiden
z
Antihistaminic—Promethazine
3. Drugs affecting brain dopaminergic system
4. Drugs affecting brain cholinergic system (Fig. 6.7)
Fig. 6.7: Drugs affecting brain cholinergic system
Opioid analgesic
Derived from poppy Paper Somniferum
Drug of choice—Opium.
From this opium, following drugs are formed.
z
Morphine—10%
z
Codeine—0.5%
z
Thebaine—0.2%
z
Noscapheine—6%
Pharmacological action
Morphine depressant
1. CNS
z
Strong analgesic
z
Sedation
z
Mood and subjective effect
z
Respiratory centre
z
Cough centre
z
Temperature, regulating centre
z
Vasomotor centre
Morphine stimulant
CTZ
Vagal centre
Edingeswestphal nucleus
1. CNS
A. Strong analgesic
z
It acts in substantia gelatinosa of dorsal horn to
inhibit the release of excitatory transmitter carrying
pain impulse,
B. Sedation
z
Drowsiness and Indifference to surrounding,
ataxia, apparent excitement.
z
Higher dose cause sleep and, no anticonvulsant
action.
C. Mood and subjective effect
z
It is very prominent and has calming in effect.
z
There is loss of apprehension for feeling of
detachment and inability to concentrate.
D. Respiratory centre
z
Depressed
z
Death in poisoning is due to respiratory failure.
E. Cough centre
z
Depressed
F. Temperature regulating centre
z
Depressed hypothalamic action.
G. Vasomotor centre
z
Depress and cause decrease in blood pressure.
Morphine stimulant
A. CTZ chemoreceptor trigger zone
z
Nausea and vomiting occur as side effect large dose
depress the vomiting centre
z
Directly emetics should not be tired in morphine
poisoning as it results in aspiration pneumonitis.
B. Vagal centre
z
It is stimulated and cause bradycardia.
C. Edigerwestphal nucleus
z
This nucleus of 3rd nerve oculomotor is stimulated and
cause meiosis and decrease in intraocular pressure.
1. Neuroendocrine
z
FSH, LH, ACTH level tend to be fall or decrease while
protecting and growth hormone increase.
2. CVS
z
Cause vasodilation with little effect on heart,
3. GIT
z
Constipation
4. Smooth muscles
Section 1 Pharmacology
73
z
Urinary bladder—tone of both derisory and sphincter
z
increased so difficulty in mixture ration.
z
Uterus—prolong labour
z
Bronchial—bronchoconstriction due to histamine
release.
5. ANS
z
Mild hyperglycemia, due to sympathetic stimulation.
Side effect
Allergy—urticaria swelling of lip
Apnoea—it occurs in newborn if it is given in pregnancynaloxane injected in cord is the treatment of choice
MULTIPLE CHOICE QUESTIONS
Acute morphine poisoning—accidental suicidal or in
drug abuse their 50-milligram intramuscular produced
serious toxicity.
Coma, flaxcidity, shallow breathing, cyanosis pinpoint
pupil, fallen blood pressure and shock, convulsion, there
is due to respiratory failure.
Antidote
1. Naloxane—0.4–0.8 mg I/V every 2–3 min increase
respiration
2. Naloprine
1. Which of the following is a leukotriene receptor
blocker?
Alprostadil B. Aspirin
A.
C. LTC4 D. Zafirlukast
2. cAMP is an example of
A. Neurohormone B. Neuromodulator
C. Neuromediator D. Neurotransmitter
3. This compound decreases the functional activities
of several CNS neurotransmitters, including
dopamine, norepinephrine, and serotonin. At
high doses it may cause parkinsonism-like
extrapyramidal system dysfunction.
Amphetamine B. Baclofen
A.
C. Diazepam D. Reserpine
4. This amine neurotransmitter is found in high
concentration in cell bodies in the pons and
brain stem; at some sites, release of transmitter is
autoregulated via presynaptic inhibition.
Acetylcholine B. Dopamine
A.
C. Glutamate D. Norepinephrine
5. Which one of the following drugs may increase
anticoagulant effects by displacement of warfarin
from plasma protein binding sites and is inactive
until converted in the body to an active metabolite?
Buspirone B. Chloral hydrate
A.
C. Clorazepate D. Secobarbital
6. This hypnotic drug facilitates the inhibitory
actions of GABA, but it lacks anticonvulsant or
muscle relaxing properties and has minimal effect
on sleep architecture.
Buspirone B. Flurazepam
A.
C. Phenobarbital D. Zaleplon
7. __________ assist GABA to it inhibitory actions,
but it does not have anticonvulant or skeletal
muscle relaxing properties and has minimal
Section 1 Pharmacology
74
impact on sleep pattern:
Buspione B. Flurazepam
A.
C. Phenobarbital D. Zaleplon
8. Carbamazepine possesses the following property
not shared by phenytoin:
A.
Modification of maximal electroshock seizures
B. Raising threshold for pentylenetetrazole
convulsions
C. Suppression of complex partial seizures
D. Amelioration of trigeminal neuralgia
9. The activity of this enzyme is specically
decreased in the Wernicke-Korsakoff syndrome
A.
Pyruvate dehydrogenas
B. Alcohol dehydrogenase
C. Cytochrome P450
D. NADH dehydrogenase
10. Which one of the following statements concerning
the pharmacokinetics of antiseizure drugs is
accurate?
A.
At high doses, phenytoin elimination follows
first-order kinetics
B. Valporic acid may increase the activity of
hepatic ALA synthase and the synthesis of
porphyrins
C. The administration of phenytoin to patients
in methadone maintenance programs has led
to symptoms of opioid overdose, including
respiratory depression
D. Although ethosuximide has a half-life of
approximately 40 hours, the drug is usually
taken twice a day
11. Withdrawal of antiseizure drugs can cause
increased seizure frequency and severity.
Withdrawal is least likely to be a problem with
A.
Clonazepam B. Diazepam
C. Ethosuximide D. Phenobarbital
12. The following is a very potent and short acting
benzodiazepine whose use as hypnotic has been
noted to cause psychiatric disturbances in some
cases:
A.
Flurazepam B. Nitrazepam
C. Triazolam D. Temazepam
13. Which one of the following statements about
phenytoin is accurate?
A.
Displaces sulfonamides from plasma proteins
B. Drug of choice in myoclonic seizures
C. Isoniazid (INH) decreases steady state blood
levels of phenytoin
D. Toxicity may occur with only small increments
in dose
14. Following is GABAB agonist
A. Muscimol B. Baclofen
C. Picrotoxin D. Bicuculline
15. Currently barbiturates are primarily used as:
A. Hypnotic
B. Sedative
C. Antiepileptic
D. Preanaesthetic medicant
16. Following is GABAA antagonist:
A. Muscimol B. Bicuculline
C. Strychnine D. Baclofen
17. Respiratory depression following use of this agent
may be reversed by administration of umazenil:
A.
Desflurane B. Fentanyl
C. Ketamine D. Midazolam
18. Use of this agent is associated with a high incidence
of disorientation, sensory and perceptual illusions,
and vivid dreams during recovery from anesthesia:
A.
Diazepam B. Fentanyl
C. Ketamine D. Midazolam
19. Which of the following was the rst compound to
be identied pharmacologically as a transmitter in
the CNS?
A.
Glycine B. Glutamate
C. Acetulcholine D. Norepinephrine
20. The preferred drug for suppressing febrile
convulsions is:
A.
Intramuscular phenobarbitone
B. Intravenous phenytoin
C. Rectal diazepam
D. Oral sodium valproate
21. Characteristics of nondepolarizing neuromuscular
blockade include which one of the following?
A.
Poorly sustained titanic tension
B. Block of post tetanic potentiation
C. Histamine blocking action
D. Significant muscle fasciculations during onset
of block
22. Disulram is used for the treatment of:
A. Acute alcoholic intoxication
B. Both physically and psychologically dependent
alcoholics
C. Alcoholics psychologically but not physically
dependent on alcohol
D. Both ‘A’ and ‘B’ are correct
23. Which of the following does not cause skeletal
muscle contractions or twitching?
Acetylcholine B. Nicotine
A.
C. Succinylcholine D. Vecuronium
24. The following is true in the treatment of epilepsy
except:
The choice of drug depends on the cause of
A.
epilepsy and not on the seizure type
B. Treatment should be instituted as early as
possible
C. Treatment is generally started with a single
drug and the other drug is added or substituted
according to response
D. Withdrawal of drug can be attempted if no
seizures have occurred for 3–5 years
25. Following is a G-protein coupled receptor
A. Metabotropic B. AMPA
C. Kainate D. NMDA
26. Which one of the following drugs has spasmolytic
activity and could also be used in the management
of seizures caused by overdose of a local anesthetic?
Baclofen B. Cyclobenzaprine
A.
C. Dantrolene D. Diazepam
27. What is considered to be the safe limit of daily
alcohol consumption by an adult man in the
absence of contraindications and interacting
drugs:
20–40 ml of whisky
A.
B. 50–100 ml of whisky
C. 120–180 ml of whisky
D. 200–300 ml of whisky
28. The major reason why carbidopa is of value in
parkinsonism is that the compound
Crosses the blood–brain barrier
A.
B. Inhibits monoamine oxidase type A
C. Inhibits aromatic L-amino acid decarboxylase
D. Is converted to the false neurotransmitter
carbidopamine
29. Which of the following is the most suitable
drug for a 6-year-old girl suffering from absence
seizures with occasional generalized tonic-clonic
seizures:
Ethosuccimide B. Sodium valproate
A.
C. Carbamazepine D. Phenytoin
30. The dopamine D2 receptor has the following
feature:
It is excitatory in nature
A.
B. It is negatively coupled to adenyl cyclase
C. It is selectively blocked by bromocriptine
D. It is not blocked by metoclopramide
31. Moderate amounts of alcohol produce the
following effects except:
Flushing
A.
B. Tachycardia
C. Diuresis
D. Rise in body temperature
Section 1 Pharmacology
75
32. The psychotic symptoms most benefited by
neuroleptic drugs are:
A.
Judgement and memory impairment
B. Loss of insight and volition
C. Hallucinations, delusions and aggressive
behaviour
D. Apathy and social withdrawal
33. Choose the correct statement from the following?
A. Muscimol is GABAB selective
B. Bicuculline is GABAA agonist
C. Picrotoxin blocks chloride channels associated
with GABAA receptors
D. Baclofen is GABAA agonist
34. The drug which abolishes the therapeutic effect
of levodopa in parkinsonism, but not that of
levodopacarbidopa combination is:
A.
Metoclopramide B. Pyridoxine
C. Chlorpromazine D. Isoniazid
35. A 30-year-old male patient is on drug therapy for
a psychiatric problem. He complains that he feels
“at” and that he gets confused at times. He has
been gaining weight and has lost his sex drive.
As he moves his had, you notice a slight tremor.
He tells you that since he has been on medication,
he is always thirsty and frequently has to urinate.
The drug he is most likely to be taking is
A.
Clonazepam B. Clozapine
C. Haloperidol D. Lithium
36. Which one of the following statements about the
action of phenothiazines is accurate?
A.
They activate muscarinic receptors
B. They are antiemetic
C. They decrease serum prolactin levels
D. They elevate the seizure threshold
E.
They raise blood pressure
37. Use of morphine in preanaesthetic medication:
A. Is restricted mostly to patients in pain
preoperatively
B. Is routine except in the presence of
contraindications
C. Is restricted to patients being anaesthetized with
ether
D. Should be made only in combination with
atropine
38. Following is the main inhibitory transmitter in
the brain:
A.
Dopamine B. Norepinephrine
C. Glycine D. GABA
39. Which one of the following drugs is most likely
to be of value in obsessive compulsive disorders
(OCD)?
A.
Clomipramine B. Amitriptyline
Section 1 Pharmacology
40. Which one of the following actions of opioid
76
C. Bupropion D. Desipramine
analgesics is mediated via activation of kappa
receptors?
A.
Cerebral Vascular dilation
B. Decreased uterine tone
C. Euphoria
D. Sedation
41. The patient is started on gembrozil. The major
mechanism of action of gembrozil is
Increased excretion of bile acid salts
A.
B. Increased expression of high-affinity LDL
receptors
C. Increased lipid hydrolysis by lipoprotein lipase
D. Inhibition of secretion of VLDL by the liver
42. A patient suffering from a depressive disorder
is being treted with imipramine. If he uses
diphenhydramine for allergic rhinitis, a drug
interaction is likely to occur because
Diphehydramine inhibits imipramine
A.
metabolism
B. Both drugs block reuptake of norepinephrine
released from sympathetic nerveendings
C. Imipramine inhibits the metabolism of
diphenydramine
D. Both drugs block muscarinic receptors
43. The antihypertensive effects of captopril can be
antagonized (reduced) by:
Angiotensin II receptor blockers
A.
B. Loop diureties
C. NSAIDS
D. Sulfonylurea hypoglycemic
44. Malignant hyperthermia is a rare complication of
use of the following anaesthetic:
Halothane
A.
B. Ketamine
C. Thiopentone sodium
D. Ether
45. Which of the following is an atypical neuroleptic
drug:
Loxapine B. Olanzapine
A.
C. Pimozide D. Flupenthixol
46. The antihypertensive drug most likely to aggravate
angina pectoris is:
Clonidine B. Guanethidine
A.
C. Hydralazine D. Methyldopa
47. This agent is currently a rst-choice drug in the
management of absence seizures as well as partial,
primary generalized, and tonic-clonic seizures.
Valproic acid
A.
B. Carbamazepine
C. Clonazepam
D. Phenytoin
48. The mechanism of action of benzodiazepines is:
Activation of GABAB receptors
A.
B. Antagonism of glycine receptors in the spinal
cord
C. Blockade of the action of glutamic acid
D. Increased GABA mediated chloride ion
conductance
49. A drug that is used in the treatment of parkinsonism
and will also attenuate reversible extrapyramidal
side effects of neuroleptics is:
A.
Amantadine B. Levodopa
C. Pergolide D. Trihexyphenidyl
50. 'Diffusion hypoxia’ is likely to occur only after
use of nitrous oxide because it:
A.
Is a respiratory depressant
B. Has low blood solubility and is used in high
concentration
C. Is a very potent anaesthetic
D. Interferes with diffusion of oxygen into the
Tissues
51. Which of the following is a common effect of
muscarinic stimulant drugs?
A.
Decreased peristalsis
B. Decreased secretion by salivary glands
C. Hypertension
D. Miosis
52. Four stages of general anesthesia are distinctly
seen with the use of:
A.
Diethyl ether B. Halothane
C. Nitrous oxide D. Enflurane
53. Which of the following sedative-hypnotic
drugs does not potentiate the CNS depressant
effects of ethanol,phenothiazines, or tricyclic
antidepressants?
A.
Buspirone B. Phenobarbital
C. Diazepam D. Chloralhydrate
54. Limitation of buspirone is:
A. A low therapeutic index
B. An extremely slow onset of action
C. A high potential of development of physical
dependence
D. Impairment of mentation or motor functions
during working hours
55. A manic patient has been brought to the hospital
with nonstop talking, singing uncontrolable
behaviour and apparent loss of contact with reality.
Which of the following is the most appropriate
drug for rapid control of his symptoms?
A.
Lithium carbonate B. Phenobarbitone
C. Haloperidol D. Valproic acid
56. Restlessness, anxiety, orthostatic hypotension,
generalized seizures, severe tremor, vivid hallucination,
and psychosis are possible symptoms of:
A.
Tolerance
B. Withdrawal
C. Drug interactions between barbiturate and
diazepam
D. None of the above
57. Benzodiazepines are least effective in:
A. Alcohol withdrawal syndromes
B. Balanced anesthesia regimens
C. Initial management of phencyclidine overdose
D. Obsessive—compulsive disorders
58. Mental retardation, microcephaly, and underde-
velopment of the mid face region in an infant is
associated with chronic maternal abuse of
Ethanol B. Amphetamine
A.
C. Cocaine D. Mescaline
59. No surgical operation should be performed during
the following stage of anaesthesia:
Stage I B. Stage II
A.
C. Stage III, plane 1 D. Stage III, plane 3
60. A woman taking haloperidol develops a spectrum
of adverse effects that include the amenorrhea
-galactorrhea syndrome and extrapyramidal
dysfunction, including bradykinesia, muscle
rigidity, and tremor at rest. Her psychiatrist
prescribes a newer antipsychotic drug that
improves both positive and negative symptoms
of schizopherenia with few of the side effects that
result from dopamine receptor blockade. Since
weekly blood tests are not deemed necessary the
drug prescribed by the psychiatrist is probably:
Bupropion B. Clozapine
A.
C. Olanzapine D. Sertraline
61. A highly selective serotonine reuptake inhibitor
is:
Sertaline B. Paroxetine
A.
C. Fluoxetine D. All of the above
62. Anticoagulation is needed immediately in a
patient with pulmonary embolism. Since there
is some concern about a possible drug-induced
thrombocytopenia, the most appropriate drug for
parenteral administration in this patient is:
Enoxaparin B. Heparin
A.
C. Ticlopidine D. Warfarin
63. Anxiolytics are used to treat:
A. Neurosis
B. Psychosis
C. Narcolepsy
D. Bipolar disorders
64. Anxiolytic agents should:
A. Relieve pain
B. Reduce anxiety and exert a calming effect
C. Improve mood and behavior in patient with
psychotic symptoms
D. Produce drowsiness, encourage the onset and
maintenance of a state of sleep
65. The following statement is correct about buspirone:
A. It interacts with benzodiazepine receptor as an
inverse agonist
B. It is a rapidly acting anxiolytic, good for panic
states
C. It produces physical dependence and suppresses
barbiturate withdrawal syndrome
D. It has anxiolytic but no anticonvulsant or muscle
relaxant property
Section 1 Pharmacology
77
66. Following general anesthetic is not metabolized:
A. Halothane B. Ether
C. Isoflurane D. Nitrous oxide
67. Indicate CNC stimulating drugs, which are the
agents of general action:
Nootropic agents B. Analeptics
A.
C. Psychostimulants D. Antidepressants
68. Which of the following agents belongs to
psychostimulants?
Meridil B. Camphor
A.
C. Piracetam D. Pantocrin
69. The appropriate chemical classification for
meperidine is:
Phenylpropylamines
A.
B. Piperazines
C. 4-phenylpiperidines
70. Which of the following neuromuscular blocking
agents can cause Muscarinic responses such as
bradycardia and increased glandular secretions?
Tubocurarine
A.
B. Succinycholine
C. Pancuronium
D. Decamethonium
71. Monoamine oxydase A:
A. Is responsible for norepinephrine, serotonin,
and tyramine metabolism
B. Is more selective for dopamine
C. Metabolizes norepinephrine and dopamine
D. Deaminates dopamine and serotonin
72. Which synapses are involved in depression?
A. Dopaminergic synapses
B. Serotoninergic synapses
C. Cholinergic synapses
D. All of the above
73. Which of the following mechanisms of action
most likely contributes to the treatment of
parkinsonism?
The direct-acting dopaminergic agonist
A.
amantadine mimics the activity of striatal
dopamine
B. The antimuscarinic activity of dophenhydramine
contributes to the restoration ofstriatal
dopaminergic-cholinergic neurotransmitter
balance
C. Striatal H1-receptors are blocked by the
antihistaminic trihexyphenidyl
D. The ergoline bromocriptine stimulates the
release of striatal dopamine from intact
terminals.
74. All the following adverse effects are associated
with the use of levodopa except:
Sialorrhea
Section 1 Pharmacology
78
A.
B. Orthostatic hypotension
C. Delusions, confusion, and depression
D. Livedo reticularis
75. Advantages of selective serotonin reuptake
inhibitors(SSRIs) include the following except:
A.
No interference with ejaculation and orgasm
B. Minimal sedative action
C. Unlikely to cause fall in BP
D. Lack of seizure precipitating potential
76. Which of the following CNS psychostimulants is
a sydnonymine derivative?
A.
Caffeine
B. Sydnocarb
C. Meridil (methylphenidate hydrochloride)
D. Amphetamine
77. Parenteral calcium is used as an antidote for which
of the following situations?
A.
Verapamil overdoses
B. Hyperkalemia
C. Cocaine intoxication
D. Verapamil overdoses and hyperkalemia
7 8. Following is inverse agonist of benzodiazepine receptors:
A. Flumazenil B. β-Carbolines
C. Chlordiazepoxide D. Glutethimide
79. Phenytoin is effective for the treatment of all of
the following types of seizures except:
A.
Generalized tonic-clonic
B. Simple partial
C. Complex partial
D. Absence
80. Indicate the second-generation heterocyclic drug:
A. Maprotiline B. Imipramine
C. Phenelzine D. Fluoxetine
81. Venlafaxine differs from standard tricyclic
antidepressants in that it:
A.
Does not inhibit 5-HT reuptake
B. Does not inhibit noradrenaline reuptake
C. Does not have anticholinergic or antiadrenergic
property
D. Has lower antidepressant efficacy
82. Which of the following anticonvulsants is
contraindicated in patients with a history of
hypersensitivity to tricyclic antidepressants?
A.
Phenytoin B. Ethosuximide
C. Acetazolamide D. Carbamazepine
83. Which of the following phenothiazine derivatives
may produce cardiac toxicity, including ventricular
arrhythmias, cardiac?
A.
Conduction block, and sudden death?
B. Thioridazine
C. Chlorpromazine
D. Perphenazine
84. Which of the following antipsychotic agents
is preferable in patients with coronary and
cerebrovascular disease?
A.
Chlorpromazine B. Fluphenazine
C. Haloperidol D. Perphenazine