09镇静催眠药——山东大学药理学英文课件.ppt

Chapter 17 Sedative-Hypnotic Drugs Definition Sedation:An effective sedative agent should reduce anxiety and exert an effect with little or no effect on motor or mental functions. Definition Hypnosis: A hypnotic drug should produce drowsiness and encourage the onset and maintenance of a state of sleep that as far as possible resembles the natural sleep state. Hypnotic effects can be achieved with most sedative drugs simply by increasing the dose. Phases of Sleep REM(rapid eye movement sleep), 25% of the total sleep, about lasts30 min dream NREM(non-rapid eye movement sleep), about 75% of total sleep, about 90 min In man, the physiological sleep consists of 4-5 cycles of alternative REM and NREM sleep NREM Stage 1 dozing and drowsiness Stage 2 major fraction, 50% of sleep Stage 3 deep sleep transition slow wove sleep Stage 4 “cerebral” sleep somnambulism and nightmare Specificity Graded dose-dependent depression of CNS function Type A sedation ? hypnosis ? anesthesia ? coma? paralysis ? failure Type B sedation ? hypnosis ? anesthesia? Specificity 2.Tolerance metabolic tolerance (enzyme inducer) pharmacodynamic tolerance(down- regulation) 3. Dependence Psychological dependence Physiological dependence Classification Benzodiazepines(BZ) Barbiturates Other Section 1 Benzodiazepines The most widely used Sedative-Hypnotics. They are more effective and safer than barbiturates. Approximately 20 benzodiezepines are currently available. Chemical Structure of BZ 1,4-benzodiazepines Classifications of BZs Drug