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CNS STIMULANTS. SAMUEL AGUAZIM. What is the definition of a CNS stimulant?. A CNS stimulant is a drug that increases motor activity, causes excitement and decreases feelings of fatigue. CNS stimulants include the methyxanthines, nicotine, and the amphetamines. CNS stimulant.

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cns stimulants

CNS STIMULANTS

SAMUEL AGUAZIM

what is the definition of a cns stimulant
What is the definition of a CNS stimulant?
  • A CNS stimulant is a drug that increases motor activity, causes excitement and decreases feelings of fatigue.
  • CNS stimulants include the methyxanthines, nicotine, and the amphetamines
cns stimulant
CNS stimulant
  • PSYCHOMOTOR STIMULANTS
  • CAUSE EXCITEMENT & EUPHORIA
  • INCREASE MOTOR ACTIVITY
  • PSYCHOTOMIMETIC DRUGS
  • PROFOUND CHANGES IN THOUGHT PATTERNS AND MOOD
  • FEW DRUGS USED CLINICALLY
  • IMPORTANT AS DRUGS OF ABUSE
methylxanthines
METHYLXANTHINES
  • What are methyxanthines? A group of psychomotor stimulants include:
  • Caffeine
  • Theophylline
  • Theobromine ( found in cocoa but of little interest)
how do methyxanthines work
How do methyxanthines work?
  • Research indicates that methyxanthines increases cyclic guanosine monophosphate (cGMP) and cyclic adenosine monophosphate (cAMP) by inhibiting phosphodiesterase and blocking adenosine receptors.
caffeine
CAFFEINE
  • What are the physiologic effects of caffeine?
  • Caffeine effects a number of organ systems within the body:
  • CNS- caffeine increases motor activity and alertness
  • Cardiovascular- caffeine increases heart rate and contractility
caffeine1
CAFFEINE
  • Smooth muscle- caffeine and its derivatives relax the smooth muscles of the bronchioles.
  • Genitourinary- caffeine can ac as weak diuretic and increase urinary output of Na+, CI- and K+
  • Gastrointestinal – caffeine stimulates secretion from the gastric mucosa. Therefore, patients who have peptic ulcer disease should be counseled to avoid caffeine
adverse effects of chronic caffeine use
Adverse Effects of chronic caffeine use?
  • At low doses- insomnia and agitation can occur
  • At higher doses (8-10g)- Emesis, convulsion and even cardiac arrhythmias can occur.
  • Do methyxanthines cross the placenta?
  • Yes, and they are secreted into the mother’s milk. Patients should be advised to avoid them during pregnancy and while nursing
theophylline
THEOPHYLLINE
  • THERAPEUTIC ROLE OF THEOPHYLLINE:
  • It can be used in the treatment of asthma, but currently it is not being used frequently because it has a very narrow therapeutic index and is not effective as the new beta agonist
nicotine
NICOTINE
  • How are the physiological effects of nicotine related to the dose?
  • In low doses, nicotine causes ganglionic stimulation by depolarization.
  • At high doses it causes ganglionic blockade
nicotine1
NICOTINE
  • What are the physiologic actions of nicotine on the central nervous system?
  • At low doses- arousal, relaxation and improved attention
  • At high doses- central respiratory paralysis caused by disruption of medullary function
nicotine2
NICOTINE
  • How does nicotine affect the peripheral nervous system?
  • At low doses- increase in blood pressure and heart rate; constriction of blood vessels to the digits and impairment of flow
  • At high doses- decrease in blood pressure and in action of GI and GU tract due to ganglionic blockade
  • NOTE: NICOTINE HAS NO THERAPEUTIC USES
nicotine3
NICOTINE
  • What is nicotine’s route of administration?
  • Absorption occurs through oral mucosa by inhalation and transdermally.
  • What are its adverse effects?
  • CNS- irritability and tremors
  • Peripheral- intestinal cramps, diarrhea, and increased heart rate and blood pressure
nicotine4
NICOTINE
  • What withdrawal symptoms do nicotine addicts experience?
  • A craving for tobacco is accompanied by irritability, restlessness, anxiety and gastrointestinal pain.
amphetamines
AMPHETAMINES
  • Name three examples of this drug class.
  • 1. methylphenidate ( ritalin)
  • 2. methamphetamine ( methedrine)-”speed”
  • 3. dextroamphetamine ( dexedrine)
amphetamines1
AMPHETAMINES
  • How do these drugs work?
  • Amphetamines work by releasing neuronal stores of catecholamines especially norepinephrine and dopamine
amphetamines2
AMPHETAMINES
  • What are the physiologic actions of these drugs?
  • Euphoria
  • Decrease in fatigue
  • Increase in blood pressure
  • Increase in rate of respiration
  • Decrease in appetite
amphetamines3
AMPHETAMINES
  • What is their clinical use?
  • Attention deficit hyperactivity disorder(ADHD)-METHYLPHENIDATE is used to alleviate this problem
  • Appetite control- amphetamines decrease appetite by blocking the receptors in the lateral hypothalamus
  • Narcolepsy
amphetamines4
AMPHETAMINES
  • What is the route of administration? Oral
  • Where are amphetamines metabolized? In the liver
  • Does physiologic and psychological dependence occur with amphetamine use?
  • Yes- amphetamines can be very addictive
amphetamines5
AMPHETAMINES
  • What are the adverse effects of these drugs?
  • Amphetamines like caffeine and nicotine affects multiple organ systems.
  • CNS-insomnia, irritability, convulsions; chronic use can lead to a psychotic state resembling schizophrenia
  • Gastrointestinal- anorexia, nausea, dry motuh
  • Cardiovascular- palpitations, angina, arrhythmias, hypertension
amphetamines6
AMPHETAMINES
  • Amphetamines are contraindicated with what group of drugs?
  • The monoamine Oxidase (MAO) inhibitors
  • How is amphetamine overdose managed?
  • Chlorpromazine is beneficial in amphetamine overdose because it blocks the alpha receptors which are responsible for the CNS disturbances and hypertension
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