• WHAT IS CENTRAL NERVOUS SYSTEM STIMULANTS
Stimulants of the central nervous system do not have a selective action. So these Excessive drugs are stimulation, not therapeutically of CNS useful. Is followed by depression. These drugs are used as analeptics. Analeptics are drugs that stimulate the CNS. They also stimulate respiration. In large doses, they produce convulsions.
•What is the classification of central nervous system stimulant
They have two types of a sort with their subparts--
1. Direct CNS stimulants
a. Cortical stimulants
• Xanthine alkaloids
• Amphetamine
• Methylphenidate
• Pipradrol
b. Medullary stimulants
•Picrotoxin
•Pentylenetetrazol
•Bemigride
•Nikethamide
•Amiphenazole
c. Spinal stimulants
•Strychnine
2. Reflex CNS stimulants Lobeline
•Ammonia
•Veratrine
•Nicotine
•WHAT IS XANTHINE ALKALOIDS:
The three xanthine alkaloids are Caffeine, present in the seeds of Coffea arabica (coffee seeds); Theophylline, present in the leaves of Thea Sinensis (tea leaves); Theobromine, present in the roots of Theobroma cacao (cocoa seeds).
• What is the Pharmacological actions OF XANTHINE ALKALOIDS:-
1. Central nervous system: Caffeine stimulates the cerebral cortex. It induces the transparent flow of thoughts and association of ideas. Motor activity is increased, and fatigue is delayed. But in large
doses, Caffeine produces headaches, confusion, and delirium. Also, Caffeine stimulates stimulation of respiratory, vasomotor, and vagal centers.
2. Cardiovascular system: Xanthines produce a direct stimulant effect on the myocardium. Also, they have dilatation of coronary and pulmonary blood vessels.
3. Miscellaneous effects of XANTHINE ALKALOIDS: Xanthines produce:
¡) relaxation of bronchial smooth muscle.
ii) decrease in fatigue of smooth muscles.
iii) diuretic effect on kidneys.
iv) increase in volume and acidity of gastric secretion.
• What is the Absorption, fate, and excretion of XANTHINE ALKALOIDS: Xanthines are well absorbed on oral and parenteral administration. They are metabolized in the liver by demethylation and oxidation. The metabolic products are excreted in the urine.
•What is Adverse reactions of XANTHINE ALKALOIDS:-
1. Confusion, insomnia, excitement, and delirium.
2. Nausea, vomiting, epigastric pain, and ulcer.
3. Tolerance and habituation.
• What are the Therapeutic uses of XANTHINE ALKALOIDS: The xanthines are helpful as antidepressants, coronary vasodilators, anti-asthmatic agents, and diuretics.
• WHAT ARE PICROTOXIN, PENTYLENETETRAZOL, NIKETHAMIDE AND BEMIGRIDE :
All these drugs are stimulants of the brain stem and medullary centers. They stimulate the respiratory center. In large doses, they produce convulsions leading to opisthotonus (i.e.arching of the back with an extension of legs and flexion of arms).
These drugs are mainly used:
1. As For analeptics, the treatment of narcotic poisoning.
2. For the diagnosis of latent epilepsy.
• WHAT IS DOXAPRAM
1. Itisa non-specific analeptic.
2. It is used as supposed to -anesthetic respiratory stimulant.
3. Adverse reactions: hypertension, tachycardia, arrhythmias, and convulsions.
• How much Dose used: 0.5 to 1.5 mg. per kg. as I.V. drip.
• WHAT IS STRYCHNINE: It is an alkaloid obtained from the button-shaped seeds of Strychnos nux vomica. Strychnine acts mainly on the spinal cord. But in large doses, it can stimulate the entire neuraxis. On oral or parenteral administration, it produces convulsions. The convulsions are characterized by tonic extension of the body and opisthotonus. After convulsions, death may occur due to asphyxia. Though strychnine increases the general activity of CNS, it is not used as a drug. The reason is, the margin between therapeutic and toxic Dose is narrow.
• Strychnine poisoning can be treated by :
1. Giving universal antidote (which contains two parts of powdered charcoal, 1 part each of magnesium oxide and tannic acid)
2. Giving paraldehyde or diazepam to control convulsions.
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