Opioids sedation

Opioids Promethazine reduces the required analgesic and anaesthetic doses of several opioids. Sedation is also increased. 

In addition to general supportive measures directed to the airway, breathing and circulation, the clinician may consider measures to decrease absorption in the alert patient they suspect has been exposed to a life-threatening dose of diphenoxylate. Charcoal may decrease absorption. Charcoal administration should be cautiously used in a patient with altered mental status to avoid charcoal aspiration pneumonitis. It is important to recognize the potential for delayed toxicity and monitor diphenoxylate poisoned patients for a minimum of 24 h. Transient recovery may be observed before this time. Repeat boluses or continuous infusion of naloxone may be necessary to reverse opioid sedating effects. 

Opioids G-protein coupled p-, 5-, k-receptors l cAMP l Ca2+ currents t K+ currents l Excitability of peripheral and central neurons l Release of excitatory neurotransmitters p, 5 sedation, nausea, euphoria/re-ward, respiratory depression, constipation k dysphoria/aversion, diuresis, sedation... 

Opioid drugs are often more effective than other nonnarcotic treatments, but they are also associated with more side effects making them less suitable for many patients. Higher doses which are more effective are also associated with undesirable effects such as sedation. 

They act as analgesics by inhibiting release of nociceptive neurotransmitters from primary afferent terminals as well as by depressing post-synaptic potentials on second order neurons. Opioid receptors are also present on some nociceptors and their expression and peripheral transport is increased upon peripheral inflammation. Peripheral opioid analgesia has been established in animal models. Although clinical studies have yielded mixed results so far, this field holds great promise. Despite side effects, such as euphoria, dysphoria, sedation, respiratory depression and obstipation and tolerance and dependence phenomena which arise upon... 

There is an increased risk of sedation and delirium with increased age. There is also an increased risk of antidopaminergic effects such as parkinsonism due to antipsychotic drugs. Many other drugs that pass the blood-brain barrier may cause adverse effects in the elderly. The response of opioids may be increased in the elderly, resulting in oversedation (Turnheim 1998). 

Behaviorai effects Opioids produce sedation, but not as profoundly as CNS depressants like barbiturates or general anesthetics. A person administered an opioid is generally lethargic but arousable. 

Opioids are sedating and cause a reduction in processing speed in clinical populations (e.g.. Digit Symbol Substitution Test) (Wood et al. 1998). However, a study in healthy subjects did not confirm these effects on digit substitution (Walker and Zacny 1998). Improvements are seen in choice reaction time after morphine administration (Hanks et al. 1995). Deficits have been reported in early-stage visual processing (O Neill et al. 1995 Hanks et al. 1995). By comparison, morphine s cognitive effects are lesser than those of lorazepam, but milder than hydromorphone (Rapp et al. 1996 Hanks et al. 1995). 

Naloxone is used for rapid opioid detoxification in conjunction with anesthetic agents for conscious sedation. 

Methadone is an opioid analgesic that is available for oral and parenteral administration. It is used in severe pain, in palliative care and as an adjunct in the management of opioid dependence. Compared with morphine, it is less sedating and has a longer duration of action. It may lead to addiction and can still cause toxicity when used in adults with non-opioid dependency. Because of the long duration of action, in overdosage, patients need to be monitored for long periods. 

Codeine, dextromethorphan and pholcodine are opioid cough suppressants indicated for dry cough. Sedating antihistamines, such as diphenhydramine, tend to have an antitussive action as well. Vitamin C is not used in the management of cough but may be used as a prophylaxis against colds. 

Tramadol is an opioid analgesic and when given to patients who are also receiving imipramine (a tricyclic antidepressant), there is an increased risk of central nervous system toxicity. The risk of occurrence of sedation is increased. 

Opioids. Activation of opioid receptors in the enteric nerve plexus results in inhibition of propulsive motor activity and enhancement of segmentation activity. This antidiarrheal effect was formerly induced by application of opium tincture (paregoric) containing morphine. Because of the CNS effects (sedation, respiratory depression, physical dependence), derivatives with peripheral actions have been developed. Whereas diphenoxylate can still produce clear CNS effects, loperamide does not Lullmann, Color Atlas of Pharmacology... 

Other indications. Acutely, there is sedation with anxiolysis after neurolep-tization has been started. This effect can be utilized for psychosomatic uncoupling in disorders with a prominent psychogenic component neuroleptanalgesia (p. 216) by means of the buty-rophenone droperidol in combination with an opioid tranquilization of overexcited, agitated patients treatment of delirium tremens with haloperidol as well as the control of mania (see p. 234). 

Pharmacology Nalmefene, an opioid antagonist, is a 6-methylene analog of naltrexone. Nalmefene prevents or reverses the effects of opioids, including respiratory depression, sedation, and hypotension. Nalmefene has no opioid agonist activity it does not produce respiratory depression, psychotomimetic effects or pupillary constriction, and no pharmacological activity was observed when it was administered in the absence of opioid agonists. Nalmefene can produce acute withdrawal symptoms in individuals who are opioid-dependent. 

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... 

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