The narcotic antagonists are drugs that bind strongly to opioid receptors but do not activate them. They block the effects of the opioid receptors and are often used to block the effects of too many opioids in the system. The narcotic antagonists in use include naloxone (Evzio) and naltrexone (ReVia).
The narcotic antagonists block opioid receptors and reverse the effects of opioids, including respiratory depression, sedation, psychomimetic effects, and hypotension.
麻醉品拮抗药阻断阿片样物质受体，逆转阿片样物质效应，包括呼吸抑制、镇静、拟心理改变效应及低血压。
These agents are indicated for reversal of the adverse effects of narcotic use, including respiratory depression and sedation, and for treatment of narcotic overdose. The narcotic antagonists do not have an appreciable effect in most people, but individuals who are addicted to narcotics experience the signs and symptoms of withdrawal when receiving these drugs rapidly.
Narcotic antagonists may be administered parenterally (subcutaneous, IM, or IV) or orally. These drugs are well absorbed after injection and are widely distributed in the body. They undergo hepatic metabolism and are excreted primarily in the urine.
Narcotic antagonists are contraindicated in the presence of any known allergy to any narcotic antagonist to avoid hypersensitivity reactions. Caution should be used in the following circumstances: During pregnancy and lactation because of potential adverse effects on the fetus and neonate; with narcotic addiction because of the precipitation of a withdrawal syndrome; and with CV disease, which could be exacerbated by the reversal of the depressive effects of narcotics.
The most frequently seen adverse effects associated with these drugs relate to the blocking effects of the opioid receptors. The most common effect is an acute narcotic abstinence syndrome that is characterized by nausea, vomiting, sweating, tachycardia, hypertension, tremulousness, and feelings of anxiety. A naloxone challenge should be administered before giving naltrexone to help to avoid acute reactions.
CNS excitement and reversal of analgesia are especially common after surgery. CV effects related to the reversal of the opioid depression can include tachycardia, blood pressure changes, dysrhythmias, and pulmonary edema.
To reverse the effects of buprenorphine, butorphanol, nalbuphine, or pentazocine, larger doses of narcotic antagonists may be needed.
为逆转丁丙诺啡、布托啡诺、纳布啡或喷他佐辛等的效应，可能需要加大麻醉品拮抗药剂量。
★Vocabulary ★
naloxone – n. 纳洛酮
Evzio – n. 埃齐奥
naltrexone – n. 纳曲酮
ReVia – n. 瑞维亚
reverse – v. 逆转
psychomimetic – a. 拟心理改变的
reversal – n. 逆转
undergo – v. 经受，经历
precipitation – n. 猛然落下，沉淀
withdrawal syndrome –戒断综合症
narcotic abstinence syndrome – 戒瘾综合症
abstinence – n. 禁戒，节制
tremulousness – n. 发抖
challenge – n. 催瘾（药）
buprenorphine – n. 丁丙诺啡
butorphanol – n. 布托啡诺
nalbuphine – n. 纳布啡
pentazocine – n. 喷他佐辛
1. The nurse would question the administration of morphine in the patient with a history of which condition?
A. Diabetes
B. Asthma
C. Anorexia
D. Cancer 2. In reviewing admission orders for a patient with a myocardial infarction, the nurse would question an order for which medication?
A. Aspirin
B. Morphine
C. Butorphanol
D. Pentazocine
奥医教育“在线自测”正式上线，复习练习、效果检验，奥医NCLEX-RN/ISPN题库一站完成。
答案 Answers
1. B. Asthma Rationale: Morphine should be used with caution in patients with asthma, emphysema, kyphoscoliosis, chronic cor pulmonale, and extreme obesity. Caution is also needed in patients taking other drugs that can depress respiration (e.g., barbiturates, benzodiazepines, general anesthetics). Morphine is indicated in the treatment of severe pain associated with cancer. 2. D. Pentazocine Rationale: Pentazocine increases cardiac work. Accordingly, a pure agonist (e.g., morphine) is preferred to pentazocine for relieving pain in patients with myocardial infarction. Morphine is the opioid of choice for decreasing the pain of myocardial infarction. With careful control of dosage, morphine can reduce discomfort without causing excessive respiratory depression and adverse cardiovascular effects. In addition, by lowering blood pressure, morphine can decrease cardiac work. If excessive hypotension or respiratory depression occurs, it can be reversed with naloxone. Because pentazocine and butorphanol increase cardiac work and oxygen demand, these agonist-antagonist opioids should generally be avoided.
当前位置：
