2. PSYCHOTROPIC DRUGS STIMULATING PSYCHOEMOTIONAL
SPHERE are psychostimulants, antidepressants, general
tonic drugs.
Increase the functional activity of the CNS is common ability
of these drugs.
Psychostimulants are divided into the
1) psychomotor stimulants and
2) psychometabolic stimulants (nootropic drugs)
Psychomotor stimulants intensify mental and physical
efficiency (especially in fatigue), minimize sensation of
weakness and temporarily reduce sleep requirements.
3. According to their chemical structure, psychomotor stimulants
are classified into the following groups:
1. Phenylalkylamines
Amphetamine (phenaminum)
2. Piperidine derivatives
Pipradol (piridrolum), Meridilum
3. Sydnonimin derivatives
Mesocarb (sydnocarbum)
4. Methylxanthines
Caffeine
4. The stimulating mechanism of amphetamine is provided
by its ability to release norepinephrine and dopamine from
the presynaptic terminals. Released catecholamines
stimulate the corresponding receptors located in the CNS.
The psychostimulating effect of amphetamine is mainly
associated with its stimulating effect on the ascending
activating reticular formation of the brainstem.
Concentration of attention and short-term memory are
enhanced, but long-term memory is inhibited after
administration of amphetamine.
5. Stimulating effect of amphetamine is associated with high
consumption of the energy resources of the body, so it is
vital to plan some rest to restore energy, otherwise intellect
flaws can occur.
Amphetamine affects the peripheral innervation. It has a
stimulating effect on α- and β-ac. As a result arterial
pressure increases and tachycardia occurs.
Using amphetamine, tolerance and drug dependence
(psychological and physical) can develop. Nowadays,
amphetamine is used rarely (due to its ability to induce
drug dependence).
6. In modern practice mesocarb is used as a
psychostimulant. The psychostimulating effect of me-
socarb develops gradually and persists over a long period
of time. Euphoria and motor excitation are not observed.
Mesocarb does not affect the cardiovascular system. It is
used in the asthenia with lethargy and in narcolepsy.
Caffeine is alkaloid is contained in tea leaves as well as
in the beans of coffee, cacao. Caffeine has
psychostimulating and analeptic properties. Caffeine
increases mental and physical efficiency, its intake leads to
a temporary elimination of both fatigue and drowsiness.
7. Direct stimulatory effects of caffeine on the brain cortex
are especially prominent.
The effect on the higher nervous activity mostly depends
on the dose of caffeine and the type of higher nervous
activity. Low doses of caffeine have a predominantly
stimulating effect, and higher doses — an inhibitory one.
Caffeine has analeptic effect since it excites respiratory
and vasomotor centers. Moreover, caffeine stimulates the
vagus nerve centers.
8. Mechanism of psychostimulating effect of caffeine is
associated with 1) inhibition of brain phosphodiesterase and
2) blockade of adenosine receptors in the brain from
adenosine brake action. Therefore, stimulating effect
prevails.
The effect of caffeine on the cardiovascular system
takes an important place in its pharmacodynamics. It results
from peripheral and central effects. Thus, caffeine has a
direct stimulating effect on the myocardium. However, the
vagus nerve centers are excited at the same time, which is
why the final effect depends on the predominance of one or
the other effect. Changes in heart function are usually rare.
9. High doses of caffeine cause tachycardia (i.e. its peripheral
effect predominates) and, sometimes, arrhythmias.
The central and peripheral components of the effect of caffeine
are also seen in its effect on vascular tone. Caffeine stimulates
the vasomotor center and increases the tone of blood vessels
and at the same time its direct effect on the vascular smooth
muscle decreases the blood vessel tone.
The arterial pressure changes in even more complex fashion
since this depends on the cardiotropic and vascular effects of
caffeine. Usually, if the initial arterial pressure is normal,
caffeine does not change it or causes a very slight increase. If
the drug is administered for hypotension the arterial pressure
increases (becomes normal).
10. Caffeine intensifies the main metabolism. It increases
glycogenolysis, causing hyperglycaemia. It increases
lipolysis.
Glandular secretion in the stomach is increased under
the effect of caffeine.
Caffeine produces a slight increase in diuresis, which
is associated with the inhibition of the reabsorption of
sodium and water ions in the proximal and distal renal
tubules. Moreover, caffeine dilates the renal vessels and
increases filtration in the renal glomerules.
11. Caffeine is used
for treatment of acute poisoning caused by drugs,
inhibiting the central nervous system,
in fatigue, migraine and arterial hypotension.
The side effects of caffeine are
nausea, vomiting, sleeplessness, tachycardia and
cardiac arrhythmias.
12. Psychometabolic stimulants (nootropic drugs)
activate the higher integrative functions of the brain. The
main effect of nootropes is their ability to favourably affect
disorders of learning and memory after long-term therapy.
These drugs increase the concentration of attention and
improve short-term memory and long-term memory.
Nootropic drugs do not affect the higher nervous activity
of healthy humans.
13. Psychometabolic stimulants are divided into 2 groups:
1. GABA-derivatives
Piracetam (nootropil)
Gammalon (aminalonum)
Phenibutum
Picamilonum
Phenotropil
2. Other chemical structure medications
Pyritinol (pyriditolum) etc.
14. The favorable effect on the metabolic (energy) processes
of the brain underlies the mechanism of
psychostimulating action of nootropes in pathological
conditions: intensification of synthesis of the macroergic
phosphates, proteins, activation of a number of enzymes,
stabilization of the impaired membranes of the neurons,
improvement of the cerebral blood circulation. Nootropic
drugs also have antihypoxic activity.
15. Nootropes are used
in organic (degenerative) lesions of the brain
(in hypoxia, cerebral injury, stroke, intoxication etc.),
in developmental delay, dementia, Alzheimer’s
disease, etc.
Side effects
sleeplessness
dyspepsia (nausea, vomiting)
16. Comparative characteristic of psychomotor stimulants and
psychometabolic stimulants
Psychomotor stimulants Psychometabolic stimulants
Are used in functional disorders
of CNS
Are used in organic disorders of
CNS
Have biphasic effect: first
stimulating, but after reduce of
the brain energy resources the
inhibitory effect appears
Have single-phase effect, which
appears after latent period,
because these drugs stimulate the
high-energy compounds synthesis
Inhibit the long-term memory Stimulate the long-term memory
Increase the consumption of
oxygen by brain
Have antihypoxic effect
17. Psychomotor stimulants Psychometabolic stimulants
Can increase the arterial
pressure
Don’t affect the arterial pressure
Some drugs (amphetamine) can
cause drug dependence
Don’t cause drug dependence
Have analeptic effect Don’t have analeptic effect
Are functional antagonists of
drugs, inhibiting the central
nervous system
No
18. Antidepressants are drugs eliminating the melancholy and
administered for the treatment of depression.
Classification
I. Drugs blocking neuronal uptake of monoamines
1. Drugs possessing nonselective action, blocking
neuronal
uptake of serotonin and norepinephrine
Imipramine (imizinum)
Amitriptyline
19. 2. Drugs possessing selective action
a) Blocking neuronal uptake of serotonin
Fluoxetine
Escitalopram
b) Blocking neuronal uptake of norepinephrine
Maprotiline
20. II. Monoamine oxidase inhibitors (MAO)
1. Non-selective action (MAO-A and MAO-B inhibitors)
Nialamide
2. Selective action (MAO-A inhibitors)
Moclobemide
III. Antidepressants different groups
Tianeptine
Agomelatinum
21. Antidepressant properties of drugs from the first group
(drugs possessing nonselective action, blocking
neuronal uptake of serotonin and norepinephrine) are
combined with marked sedative effect.
They also have peripheral M-cholinoblocking, α1-
adrenoblocking and antihistamine effects.
Side effects
atropine-like effects: the dryness of the oral mucous
membrane, tachycardia, urinary retention etc.
arterial hypotension
marked sedative effect
22. Drugs with selective action, blocking neuronal uptake of
serotonin, don’t have sedative, M-cholinoblocking, α1-
adrenoblocking effects.
Antidepressant properties of monoamine oxidase
inhibitors are combined with marked psychostimulating
effect.
Side effects
sleeplessness
hepatotoxicity
orthostatic collapse
