nullToxicity, Sedative-Hypnotics
中山急诊 姚晨玲Toxicity, Sedative-Hypnotics
中山急诊 姚晨玲Background Background Sedative-hypnotics are a group of drugs that cause CNS depression.
Benzodiazepines (BZD)
barbiturates
nonbarbiturate nonbenzodiazepine sedative-hypnotics (NBNB)the most commonly used agents BackgroundBackgroundacute sedative-hypnotics poisoning
withdrawal syndromeEtiologyEtiologyBenzodiazepines (BZD)
Long acting (half life >30h):
chlordiazepoxide (利眠宁)
diazepam(地西泮、安定)
flurazepam (氟安定)
Short acting (half life 6-30h):
alprazolam(阿普唑仑)
Ultrashort acting :
triazolam(三唑仑)
EtiologyEtiologyBarbiturates
Ultrashort acting
Methohexital (Brevital甲己炔巴比妥)
thiopental (Pentothal硫喷妥那)
Short acting
pentobarbital (Nembutal戊巴比妥)
secobarbital (Seconal司可巴比妥)
Intermediate acting
Amobarbital (Amytal异戊巴比妥)
butalbital (Fioricet, Fiorinal异丁巴比妥)
Long acting
Phenobarbital (Luminal鲁米那)EtiologyNonbarbiturate, nonbenzodiazepine sedative-hypnotics (NBNB)
Chloral hydrate (水合氯醛)
Ethchlorvynol (乙氯维诺)
Glutethimide (导眠能)
Methyprylon (甲乙哌酮)
Meprobamate (眠尔通)EtiologyPathogenesisPathogenesis一、Pharmacokinetics :
1、Pharmacokinetics of the BZD
Most BZD are extensively metabolized by the liver.
Some are metabolized to products which are active
and may have a much longer half life than the parent
drug.
The major route of metabolism is N-demethylation.
in the elderly
Cimetidine PathogenesisPathogenesis2、Pharmacokinetics of Barbiturates
Barbiturates with low lipid solubility are excreted in the unchanged form by the kidneys. ie phenobarbital(苯巴比妥).
Barbiturates with high lipid solubility are metabolized to more polar compounds in the liver before being excreted via the kidneys. ie thiopental (硫喷妥). PathogenesisPathogenesis3、Pharmacokinetics of NBNB
Most NBNB are extensively metabolized by the liver
Pathogenesis BZD
In the CNS, benzodiazepines exert their clinical effect by enhancing the activity of the inhibitory neurotransmitter GABA.
(The clinical effects of GABA release and GABA-gated chloride channels include sleep induction and excitement inhibition)
Barbiturates
in prolongation of the duration of opening of GABA-gated chloride channels, leading to hyperpolarization of the membrane and suppression of neurotransmission. 。
NBNB
similar to the action of Barbiturates二、 The mechanism of actionPathogenesisnullBZD
GABAchloride channelCl-Cl-+++++-----hyperpolarizationClinicalClinicalBenzodiazepine
blurred vision, dizziness, confusion, drowsiness, anxiety, agitation, and unresponsiveness or coma.
BZD overdose in itself is remarkably safe. most patients with benzodiazepine overdose can be managed in the ED and released home after appropriate care.
When combined with other sedatives (most frequently alcohol), patients with benzodiazepine overdose can present with profoundly depressed levels of consciousness. .
ClinicalClinicalBarbiturates
Mild intoxication is characterized by ataxia, incoordination, nystagmus, slurred speech, and altered level of consciousness.
Moderate poisoning leads to respiratory depression and hyporeflexia.
Severe poisoning leads to flaccid areflexic coma, apnea, and hypotension.
Occasionally, hyperreflexia, rigidity, clonus, and Babinski signs are present.
Miosis is common, but mydriasis may be present with certain agents.
Generally, 10 times the hypnotic dose produces severe toxicity.ClinicalClinicalChloral hydrate
Mild intoxication is characterized by ataxia, lethargy
Severe poisoning leads to stupor, coma, pinpoint pupils, hypotension, slow or rapid and shallow respiration, hypothermia, areflexia, and muscle flaccidity.
Arrhythmias ClinicalGlutethimide (Doriden)
Loss of brainstem reflexes
Flaccidity
Anticholinergic effects
Delayed gastric emptying
May cause hyperthermia or heatstroke
Clinical
ClinicalClinicalMethaqualone (Quaalude)
Resembles barbiturate poisoning
Has more pronounced motor problems (eg, ataxia) and is known as wallbanger because of this phenomenon.
Can lead to severe muscular hypertonicity and seizures
Lab Studies Lab Studies Obtain a complete blood count (CBC), arterial blood gas (ABG), glucose, chemistry,
Imaging Studies:
Obtain an abdominal x-ray. Chloral hydrate is radiopaque.
Other Tests:
Obtain an electrocardiogram (ECG); Co-ingested drugs may have direct cardiac effects (eg, tricyclic antidepressants). Lab Studies Lab Studies Quantitative serum drug concentrations are recommended for patients with serious toxicity
Barbiturates: For short-acting drugs, the lethal dose is 3 g or a serum concentration higher than 3.5 mg/dL. For long-acting drugs, the lethal dose is 5-10 g or a concentration higher than 8 mg/dL.
Chloral hydrate: The lethal dose is 10 g and a concentration higher than 100 mg/mL is toxic DiagnosisDiagnosisHistory
Symptom and sign
serum drug concentrations
DifferentialsDifferentialsToxicity, Alcohols
Hypoglycemia
Diabetic Ketoacidosis
Neoplasms, Brain TreatmentTreatmentEmergency Department Care
Establish ABCs, obtain IV access, provide oxygen
Ensure adequate airway and ventilation. Do endotracheal intubation if necessary.
Fluid resuscitation and anti-shock
Naloxone is recommended to the patients with comma.
TreatmentTreatmentPrevention of absorption
Gastric lavage may be performed if the patient presents obtunded within 2hour of ingestion
Activated charcoal is recommended for sedative-hypnotic overdoses. Multi-dose activated charcoal (20-50 g q4h) is recommended for overdoses with barbiturates, glutethimide, and meprobamate.
TreatmentTreatmentElimination enhancement
Alkaline diuresis enhances elimination of phenobarbital and other long-acting barbiturates. It is recommended for all symptomatic patients with long-acting barbiturate toxicity.
Consider hemodialysis or hemoperfusion in glutethimide, methyprylon, phenobarbital, meprobamate, and chloral hydrate poisoning.TreatmentTreatmentDetoxicant Flumazenil
Flumazenil competitively and reversibly binds benzodiazepine receptors (ie, GABA).
The use of flumazenil for suspected benzodiazepine overdoses is controversial. If used, it should be administered slowly (0.2 mg/min up to 3-5 mg) because large doses cause agitation and withdrawal.
This drug is contraindicated in patients with increased intracranial pressure (ICP) or closed head injury (CHI), those with a history of epilepsy, or those known to have ingested a tricyclic antidepressant (TCA) agent
Treatment of complicationTreatment of complicationPneumonia
Arrhythmias
Acute renal failure
nullPrognosis
prophylaxis
本文档为【姚晨玲-镇静催眠药中毒】,请使用软件OFFICE或WPS软件打开。作品中的文字与图均可以修改和编辑,
图片更改请在作品中右键图片并更换,文字修改请直接点击文字进行修改,也可以新增和删除文档中的内容。
该文档来自用户分享,如有侵权行为请发邮件ishare@vip.sina.com联系网站客服,我们会及时删除。
[版权声明] 本站所有资料为用户分享产生,若发现您的权利被侵害,请联系客服邮件isharekefu@iask.cn,我们尽快处理。
本作品所展示的图片、画像、字体、音乐的版权可能需版权方额外授权,请谨慎使用。
网站提供的党政主题相关内容(国旗、国徽、党徽..)目的在于配合国家政策宣传,仅限个人学习分享使用,禁止用于任何广告和商用目的。