中枢兴奋药 Central Stimulants

中枢兴奋药Central Stimulants 北京协和医学院基础医学院药理学系叶菜英

Central Stimulants Definition: • Drugs that can stimulate the central nervous system. Classification: • Cerebral cortex stimulation: Caffeine, Theophylline… • Cerebrum and brain stem stimulation: Nikethamide, Dimefline and Lobeline. • Spinal cord stimulation: Strychnine

Caffeine(咖啡因) 【Mechanism of Action】 • Inhibit phosphodiesterase, decrease the degradation of cAMP→cAMP↑…… →physiological effect • Central neuromodulator antagonist → effect of adenosine →block the inhibiting effect of adenosine on central nervous system→stimulate the central nervous system. • Increasing intracellular free calcium • Competitive antagonists of Benzodiazepine receptor, decrease the open frequency of Cl－channel→stimulate the central nervous system.

Caffeine 【Pharmacologic properties and clinical application】 • CNS：In small doses , it causes wakefulness, increases mental alertness, and decreases response times for simple motor task. • Cardiovascular effects：Small doses →stimulate vagus nerve→heart rate↓ Large doses→increase the sensitivity of heart rate→arrhythmia • Vasoconstriction effects: use with Ergotamine, brain arteriectasis→treatment of migraine, usually compatible with antipyretic analgesic→cold, headache, hypertension headache（APC、Somedon）.

Caffeine 【Adverse effect】 Rare. • Stimulation, discomfortable, insomnia • Overdose→tachycardia • Toxis→muscle tremor

Lobeline (洛贝林 ) 【Pharmacologic properties】 • Stimulate carotid body and aortic chemoreceptor, stimulate respiratory center reflectivity. • Large doses Lobeline can stimulate medulla oblongata respiratory center directly. • Stimulate sympathetic nerve→increase in the heart rate, BP↑ • Take effect rapidly, hold time is short (several minutes). • Lobeline is often used to improve respiratory depression which induced by neonatal asphyxia and pedo-infectious diseases, it also can improve respiratory failure which induced by drug intoxication and CO2 intoxication. • Adverse effect：increase in the heart rate，overdose→convulsion

Nikethamide(尼可刹米) ( Coramine可拉明) 【Pharmacologic properties】 • Increase the stimulation of CNS, especially stimulate medulla oblongata respiratory center, carotid body and aortic chemoreceptor, and then, stimulate respiratory center reflectivity, increase the CO2 sensitivity of CNS, accelerating and deepening breathing, improving respiratory function. • The stimulate effect of cerebral cortex vasomotor center and spinal cord is weak. • Take effect rapidly, hold time is short ，a single intravenous bolus can maintain 5 to 10 minutes.

Nikethamide（Coramine） • Clinical application: various kinds of centralrespiratory depression (neonatal asphyxia, CO2 intoxication，drug intoxication). • Adverse effects are rare. Overdose→BP↑，tachycardia, amyostasia and rigor, cough, vomiting, perspiration. Toxis→convulsion.

Central Stimulants 【Clinical application】 • Application conditions of Respiratory Stimulants: trachea is smooth, and respiratory muscle is normal （no obviouslysputamentum retention and bronchospasm）. • Combination measures: etiological treatment inhaling O2, artificial respiration. The holding time of central stimulants is short, so it should be used again and again. • Prevent convulsion（Overdose→ convulsion ）：several kinds of drug can be used taking turns, control doses strictly→→→

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中枢兴奋药 Central Stimulants