Opioids mental effects

Thompson, T, Hackenherg, T, Cerutti, D., Baker, D., and Axtell, S. (1994) Opioid antagonist effects on self-injury in adults with mental retardation response form and location as determinants of medication effects. Am J Ment Retard 99 85—102. 

Tolerance to the mental effects of opioids develops with long-term use. The need for ever-increasing amounts of drugs to sustain the desired euphoriant effects—as well as to avoid the discomfort of withdrawal—has the expected consequence of strongly reinforcing dependence once it has started. The role of endogenous opioid peptides in opioid dependence is uncertain. 

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. 

T. Thompson, T. Hackenberg, D. Ceiruti, D. Baker, and S. Axtell, Opioid Antagonist Effects on Self-injury in Adults with Mental Retardation Response Form and Location as Determinants of Medication Effects. Am. J. Mental Retardation, 99,85-102,1994. 

The behavioral effects of nicotine have been defined as both stimulant and depressant, effects that are influenced by the present mental status and expectations of the smoker. Smokers may feel alert and relaxed. Nicotine produces myriad effects on the central nervous system (CNS), almost all of which appear to be mediated through nicotinic receptors. Additionally, nicotine influences multiple neuronal systems. One of its most prominent effects is stimulated release of dopamine, particularly in the nucleus accumbens, which is a major component of the reward system. Nicotine also stimulates the release of endogenous opioids and glucocorticoids. 

Behavioral effects of opioids include euphoria, sedation and mental clouding. Physiological effects include respiratory depression, decreased heart rate, contraction of the pupil, constipation, nausea, and vomiting. Opioids can also release histamine from body stores, causing severe itching, hypotension, sweating, and flushing. 

In addition to their use as pharmacological tools, selective 8 opioid antagonists may have clinical potential in the treatment of a variety of disorders where endogenous opioids play a modulatory role, e.g. disorders of food intake, shock, constipation, mental disorders, CNS injury, alcoholism, drug addiction and immune function (Spetea et al., 2001). It is also worth mentioning that 8 antagonists have been shown to possess an antitussive effects in rodents, thus indicating another possible clinical application for these compounds (Kamei et al., 1994). 

Behavioral disturbances and aversive effects in particular have been observed when naltrexone has been used for treatment of opioid dependence symptoms noted were loss of energy, gastrointestinal disturbances, and mental depression. 

Reversible hepatocellular injury has been reported with naltrexone in doses of up to 300 mg/day, which is five times that usually used for opioid blockade (SED-11, 147) (17). Five of twenty-six patients treated with naltrexone for obesity developed raised serum transaminase activities after 3-8 weeks of treatment. In another study in which 60 obese subjects received naltrexone for 8 weeks, there were abnormal liver function tests in six patients. Three patients failed to complete the course. Nausea and vomiting occurred within the first 24 hours of treatment but responded to a reduction in dose. There were also changes in mentation such as decreased mental acuity, depression, and anxiety, all of which resolved after withdrawal. This is significant, as adverse effects from naltrexone have previously been attributed to mild physical withdrawal syndromes. 

Nefopam, an orphenadrine derivative, is a centrally acting non-opioid analgesic. Various adverse effects have been reported, including nausea, vomiting, epigastric pain, dizziness, drowsiness and mental confusion, hypotension, tachycardia, skin rashes, xerostomia, and urinary retention some of these may be related to its anticholinergic properties (SEDA-11, 100). Its unsatisfactory adverse effects profile was confirmed in two studies of pain control in cancer and rheumatoid arthritis (SEDA-15, 104)... 

UNTOWARD EFFECTS AND PRECAUTIONS Morphine and related opioids produce a wide spectrum of unwanted effects, including respiratory depression, nausea, vomiting, dizziness, mental clouding, dysphoria, pruritus, constipation, increased pressure in the biliary tract, urinary retention, hypotension, and rarely dehiium. Increased sensitivity to pain after analgesia has worn off also may occur. 

The incidence of serotonin syndrome-like reactions with opioids and SSRIs is fairly rare (although see tramadol , (p.l222)) however, the possibility of the serotonin syndrome , (p.9), should be considered in patients experiencing altered mental status, autonomic dysfunction and neuromuscular adverse effects while receiving these drugs. 

The term mental dependence is based on the euphoric effect of opioids. The loss of euphoria, concurrent with the appearance of physical withdrawal symptoms, makes it even more difficult for patients to overcome their addiction. For the therapeutic treatment of addiction, as well as for acute opiate poisoning, opiate antagonists (e.g. Naloxone) have been developed. 

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