Oxygen Opiates

The effects of corticosteroids, cyclooxygenase blockers, leukotriene blockers, PAF antagonists, anti-TNF antibodies, oxygen radical scavengers, opiate antagonists, antihistamines, and calcium channel blockers in endotoxic shock were reviewed in 1990 (H17). In this section studies on this subject that have been published during the last few years are summarized. 

Pain Action Unknown but may stimulate opioid sites, sedation and analgesia Dose Adults. Self administered inhalation (generally 25-50% w/ oxygen) until pain relief or pt drops mask/falls asleep Peds. Same as adult (onset w/in 2-5 min) Caution [ , ] Do not use after full meal Contra EtOH intox AMS following head injury COPD, thoracic trauma Disp Supplied in blue cylinders SE N/V, Light-headedness, AMS and hallucinations Interactions T CNS depression Wf opiates, EtOH, sedatives EMS Do not strap mask to pt s face, allow pt to hold the mask to their face dosing is self-limiting when pt drops mask d/t CNS depression typically used for bums and fractures... 

Certain forms of dyspnea yield only to opiates. Especially in this category is the dyspnea of acute left ventricular failure and pulmonary edema. Most authorities agree that morphine is contraindicated in patients with pulmonary edema caused by chemical respiratory irritants. If needed in such cases for severe pain, its use should be combined with oxygen inhalation and positive-pressure therapy. In bronchial asthma, morphine is usually contraindicated because there is danger of addiction, the drug tends to depress respiration and to constrict bronchioles, and patients with asthma may be allergic to the drug. Deaths have occurred from the use of morphine in asthma. 

One of the serious complications of the use of the opiate analgesics, even at therapeutic doses, is respiratory depression, an effect which is further complicated by the ability of these drugs to decrease the sensitivity of the respiratory centre to carbon dioxide. The administration of oxygen to a patient whose respiration has been depressed by the opiates is therefore counterproductive and may lead to total respiratory paralysis. 

Like morphine, most analgesically active morphinans bear an oxygen function, usually as hydroxyl, in position C-3. The presence of 3-OH or 3-OAc invariably leads to a significant enhancement of opiate activity in these series, whereas 3-OMe affords, at best, a modest activity increase/81 Other 3-position substituents significantly reduce or abolish activity. 

Morphinans bearing a 6-oxygen function have proved to be a valuable source of precursors for the synthesis of natural opiates/53,55 58 Compounds such as dihydrothebainone (64, R = OMe R = H) may be derived from thebaine, whereas others are totally synthetic/8 ... 

Recent studies on both morphinans and 4,5-epoxymorphinans have posed several questions For example, clarification of the role of the C-3/C-4 oxygen and the C-6, C-7, C-8, C-14 region of the morphinan C-nng in the union of opiate with its receptor(s) is required... 

This is especially true since a number of Ca2+-dependent effects are known to be susceptible to opiate action. The picture is further complicated by the possibility that in some cases opiate effects may not involve Ca +, while in the instances where opiate-Ca + interactions can be demonstrated, the effects on Ca + may be either directly related to drug action or may be the indirect consequence of other opiate actions such as effects on body temperature, pH or oxygen tension. 

Alfentanil, an opiate analgesic (8 to 50 mcg/kg IV), is indicated as an adjunct to general anesthetic in the maintenance of general anesthesia with barbiturate, nitrous oxide, and oxygen. In addition, it is used as a primary anesthetic for induction of anesthesia when endotracheal intubation and mechanical ventilation are required. 

The specific cellular and biochemical mechanisms mediating septic shock and ARDS are undefined. Current concepts favour inflammatory mediators, a number of which have been implicated in experimentally induced sepsis and ARDS. These include oxygen free radicals, endogenous opiates, kinins, angiotensin, histamine, serotonin and catecholamines . ... 

The addition of ketamine as an opiate sparer, 1.5 or 5 mg per bolus morphine dose, has been studied in 58 patients undergoing transthoracic heart and lung surgery, a procedure that is associated with severe pain [122 ]. Those who took ketamine used 50% less morphine and required less rescue diclofenac for pain control. Pain scores were consistently lower with ketamine, despite reduced amounts of morphine administered. Respiratory parameters were much better with ketamine none compared with seven patients requiring oxygen for hypoxia. The... 

In the management of an opiate knockdown agent exposure, early airway and ventilation assessment is essential and intermittent positive pressure ventilation with 100 % oxygen should start as soon as possible if there is a respiratory failure. An antidote to the respiratory depression caused by opiates is naloxone which is used both in anaesthetic and clinical toxicological practice. This is given in doses of 0.4 mg IV repeated until there is a reversal of the respiratory depression. It should be noted that in cases of mixed injury where opioids may have been given for pain relief, the analgesic effect will also be reversed. 

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