Anesthesia sedative-hypnotics causing

Barbiturates are referred to as sedative-hypnotics. These drugs will induce sleep which can lead to even deeper sedation (hypnosis) and can cause a fatal depression of the RAS affecting the respiratory system. The sleep which is encountered does not have the normal cycles of slow wave and rapid eye movement activity, so it is not always restful. However, these agents prove to be useful in anesthesia for both short and longer durations of time. Many of you may have been given thiopental prior to wisdom tooth extraction. Thiopental "wears off quickly and so the actual anesthetic for the time of the extraction is usually nitrous oxide. 

Propofol [pro POF ol] is an IV sedative/hypnotic used in the induction or maintenance of anesthesia. Onset is smooth and occurs within about 40 seconds of administration. Supplemenation with narcotics for analgesia is required. While propofol facilitates depression in the CNS, high plasma levels can cause excitation. Propofol decreases blood pressure without depressing the myocardium. It also reduces intracranial pressure. 

The clinical effects of sedative-hypnotics include sedation and sleep. Sedative-hypnotic drugs depress the function of the CNS and in a dose-dependent fashion produce drowsiness (sedation). Several sedative-hypnotic drugs, especially the older ones, produce sedation, sleep, unconsciousness, surgical anesthesia, coma, and ultimately may cause fatal depression of respiration and cardiovascular regulation. 

With increased doses, the patient experiences a hypnotic effect causing the patient to fall asleep. Even higher doses of sedative-hypnotics anesthetize the patient. Such is the case of the ultra-short-acting barbiturate thiopental sodium (Pentothal) that produces anesthesia. 

Respiratory drive and rhythm are depressed by barbiturates. Coughing, sneezing, hiccupping, and laryngospasm may occur during anesthesia with barbiturates. Sedative ot hypnotic doses of barbiturates teduce heatt tate and blood pressure to levels found in normal sleep. Anesthetic doses produce more pronounced effects. Barbiturates cross the placenta when used in labor, they can cause respiratoty depression in neonates. Anesthetic doses dectease force and frequency of uterine contractions among pregnant women. 

Droperidol is used as an adjunct for induction and maintenance of general anesthesia and as an anesthetic in diagnostic procedures. Droperidol, which has antiemetic properties, causes marked sedation and potentiates the CNS depressant effects of alcohol, hypnotic-sedatives, and numerous psychoactive agents. Droperidol is absorbed well through an IM injection—sedation begins in 3 minutes, peaks at 30 minutes, and lasts for 2 to 4 hours. Droperidol is metabolized by the liver to p-fluoro-phenylacetic acid and p-hydroxypiperidine, and its metabolites are excreted in urine and feces. 

Barbiturates are derivatives of barbituric acid. These substances were once used extensively in clinical practices as sedatives-hynotics. Because of their abuse and physical dependence, their therapeutic application has diminished considerably. The sedative effects of barbiturates are similar to those of alcohol. Higher dosage can cause hypnosis and anesthesia. An intake of barbiturates 10-15 times that of the hypnotic dose can be toxic. Coma and death can result from overdose. 

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