Đang chuẩn bị liên kết để tải về tài liệu:
Toxicology A Case-Oriented Approach - part 8

Nôn nhiều ingestions độc nên đã cố gắng tiếp xúc bằng miệng. Trong thực tế, ingestions dạng thuốc phiện chậm làm rỗng dạ dày, làm tăng hiệu quả có thể xảy ra của phương thức điều trị này. | TABLE 20.3 Comparison of the Toxic Properties of Opiates Drug Equivalent Dose mg Therapeutic Concentration mcg mL Toxic Concentration mcg dL Lethal Concentration mcg dL Morphine 10 1-8 10-100 400 Codeine 120 1-12 20-50 60 Heroin 3-4 10-100 400 Methadone 8-10 30-100 200 400 Meperidine 80-100 30-100 500 2000 Hydromorphone 1.5 0.1- 3 10-200 300 Oxycodone 15 1-10 20-500 myocardial depression rhabdomyolysis seizures and coma. Toxic doses of morphine and other opiates are shown in Table 20.3. Therapy As in many poisonous ingestions emesis should be attempted if the exposure was oral. In fact opiate ingestions delay gastric emptying which increases the probable efficacy of this mode of therapy. Gastric lavage should be employed for unconscious patients. Because the opiates suppress respirations and have many other effects the opiate-poisoned patient is likely to require immediate attention to vital functions. Thus assure that respiratory function and cardiovascular action are adequate before other interventions. For opiates a class of compounds exist which effectively reverses almost all of the symptoms of opiate overdose. These are opiate antagonists such as naloxone Figure 20.10 . Naloxone Narcan is a pure opioid antagonist i.e. it has no actions that are additive to those of opiates. By contrast some compounds such as levallorphan have partial agonist action which means that it has some morphine-like behavior for example it can promote sedation. Naloxone is the antidote of choice for opiate overdose and it dramatically improves respiration in just 1 or 2 minutes. It is also highly potent with 0.4 mg being the usual dose. When given to a patient whose coma is not due to opiates there is usually no toxicity whatever. For this reason naloxone is often tried for patients with coma of unknown etiology. It has a short half-life of about 60 minutes. It may therefore need to be given repeatedly because it is extremely likely to disappear from the blood while the morphine or .