Sedative-hypnotic drugs overdose

Nontolerant individuals who consume alcohol in large quantities develop typical effects of acute sedative-hypnotic drug overdose along with the cardiovascular effects previously described (vasodilation, tachycardia) and gastrointestinal irritation. Since tolerance is not absolute, even chronic alcoholics may become severely intoxicated if sufficient alcohol is consumed. 

An understanding of common mechanisms of death due to poisoning can help prepare the care-giver to treat patients effectively. Many toxins depress the central nervous system (CNS), resulting in obtundation or coma. Comatose patients frequently lose their airway protective reflexes and their respiratory drive. Thus, they may die as a result of airway obstruction by the flaccid tongue, aspiration of gastric contents into the tracheobronchial tree, or respiratory arrest. These are the most common causes of death due to overdoses of narcotics and sedative-hypnotic drugs (eg, barbiturates and alcohol). 

The benzodiazepines (BZDs), which were introduced nearly 40 years ago, were hailed as a breakthrough because they have fewer of the drawbacks of prior anxiolytics and sedative-hypnotics, are effective in a range of disorders, and are safe in combination with most drugs (except other sedatives), as well as alone in overdose, and are generally mild in terms of side effects. For these reasons, BZDs quickly became, and remain, among the most widely prescribed drugs worldwide. 

Glutethimide (Doriden), a highly lipid-soluble drug classified as a sedative-hypnotic, was introduced in 1954 as a safe barbiturate substitute. However, its addiction potential and the severity of withdrawal symptoms were similar to those of barbiturates. In 1991, glutethimide was classified as a Schedule II controlled substance in response to an upsurge in the prevalence of diversion, abuse, and overdose deaths. The drug is illegal in the United States and in several other countries. It is classified as a sedative-hypnotic. 

Diazepam is used primarily in the treatment of mental anxiety. In addition, it acts as a muscle relaxant for a variety of medical conditions. It may also be used as a sedative-hypnotic and anticonvulsant (e.g., for status epilepticus and drug-induced seizures). Diazepam may also be used to alleviate some of the symptoms associated with the following cholinesterase poisoning, substance abuse withdrawal, antihistamine overdose. Black Widow spider envenomation, and chloroquine overdose. As an anesthetic, diazepam may be used alone or in combination with other drugs for conscious sedation. 

B. Toxicodynamics Toxicodynamics is a term used to denote the injurious effects of toxins, ie, their pharmacodynamics. A knowledge of toxicodynamics can be useful in the diagnosis and management of poisoning. For example, hypertension and tachycardia are typically seen in overdoses with amphetamines, cocaine, and antimuscarinic drugs. Hypotension with bradycardia occurs with overdoses of calcium channel blockers, beta-blockers, and sedative-hypnotics. Hypotension with tachycardia occurs with tricyclic antidepressants, phenothiazines, and theophylline. Hyperthermia is most frequently a result of overdose of drugs with antimuscarinic actions, the salicylates, or sympathomimetics. Hypothermia is more likely to occur with toxic doses of ethanol and other CNS depressants. Increased respiratory rate is often a feature of... 

Aspirin, sympathomimetics, agents with muscarinic blocking actions, and drugs that cause muscle rigidity or seizures are all likely to cause hyperthermia at toxic doses. Hypothermia is more typical of overdoses with opioids or sedative-hypnotics. The answer is (C). 

Any new hypnotic should induce and maintain natural sleep without producing residual sedative effects during the day it should not cause dependence or interact adversely with other sedatives, including alcohol. The ideal hypnotic should not cause respiratory depression or precipitate cardiovascular collapse when taken in overdose. So far no drug fulfils all these criteria. 

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