CNS_stimulants

CNS_stimulants

• 1.
  Central Nervous SystemStimulants • These Drugs Primarily Stimulate The Nervous System And Improve Certain Brain Functions. • Relatively Nonspecific Drugs In Action And Affect All Parts Of Body When Given In Sufficient Dose. • Adverse Side Effects Are Seen And Potential Of Abuse. So only few drugs are in practice.
• 2.
  CLASSIFICATION: 1. Psychostimulants/Cerebral Stimulants Xanthines/Methylxanthines Eg: Caffeine  Amfetamines Eg: Amfetamine And Methamphetamine  Norepinephrine-dopamine Reuptake Inhibitors Eg: Methylphenidate  Ampakines Eg: Ampalex And Cardophen  Miscellaneous Drugs Eg: Modafinil And Adrafinil
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  2. Brain StemStimulants / Analeptics Eg: Doxapram, Bemegride. 3. Convulsants Eg: Strychine, Brucine, picrotoxin. 4. Psychotomimetics / Hallucinogen Eg: Cannabis, LSD, Mescaline.
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  1. PSYCHOSTIMULANTS Psychoactive drugswhich mainly affects sensory cortex. Stimulate motor cortex only in high dose.
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  a) Xanthines andMethylxanthines [Caffeine] MOA: Inhibition of phosphodiesterase enzyme. Degradation of cyclic nucleotides. Antagonism with adenosine . Production of dis-inhibitory effect and increased alertness. Dose: Dogs : 100-1000mg, hypodermically
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  b) Amfetamines Powerful psychostimulant with risk of drug abuse and drug dependence. MOA: Transportation from extra neuronal space into adrenergic and dopaminergic nerve. Into storage vesicles via vesicular monoamine transporter. Displaces and releases nor-epinephrine and dopamine through same carrier into synaptic cleft. Increase in alertness and anorectic effects.
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  c) Norepinephrine- DopamineReuptake Inhibitors Used in treatment of attention deficit hyperactivity disorder (ADHD) & depression. MOA: INHIBIT REUPTAKE OF NEUROTRANSMITTERS. (NOR-EPINEPHRINE & DOPAMINE) ACCUMULATED NEUROTRANSMITTERS IN THE SYNAPSE. ENHANCED NEUROTRANSMISSION & STIMULANT EFFECT.
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  d) Ampakines • Enhancealertness and attention as well as facilitate learning and memory. • Used in Alzheimer’s disease, Parkinson’s disease or other neurological disorders. • Not known to be used in veterinary medicine.
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  e) Modafinil AndAdrafinil • Memory improving and mood enhancing psychostimulants. • The MOA is not completely known however they are suggested to be similar to Amfetamines.
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  2. BRAINSTEM STIMULANTS/ANALEPTICS DOXAPRAM MOA: Stimulateschemoreceptors in carotid and aortic bodies. Stimulation of respiratory centre in brain stem.(medulla) Increase in tidal volume and respiratory rate.
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  3. CONVULSANTS A) StrychnineAnd Brucine MOA: Antagonism with glycine. inhibitory neuro-transmitter action. Enhanced reflex stimulation. Uncontrolled excitation.
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  B) PICROTOXIN MOA: Antagonist forGABA receptors. Chloride channel blocked. Inhibitory neurotransmitters suppressed.
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  4. PSYCHOTOMIMETICS/HALLUCINOGENS Alter mood,behavior, thought, emotion & perception. Mimic the symptoms of pyschosis including delusion.