Side effects opiates

When reversing opiate side effects in patients needing analgesia, dilute and titrate (0.1-0.2 mg q 2-3 minutes) so as not to reverse analgesia... 

Opiate-Related Agents Opiate-related agents are synthetic compounds similar to opiates. Side effects are nausea, vomiting, drowsiness, abdominal distention, Tachycardia, paralytic ileus, urinary retention, decreased secretions, and physical dependence. Two common opiate-related agents are ... 

The immune system plays a major role in pain. Under pain situations, IL-1 induces a decrease inthe level of CRF, cortisol, and p-endorphin (Bessler, et al., 1996 Parsadaniatz, et al., 1997). CRF alone releases p-endorphin. IL-1 alone has the similar effect—releasing P-endorphin. n-3 Fatty acids protected the rats from opiate side effects (Frances, et al., 1996, Hargreaves et al., 1990, Jones et al., 1999). IL-1, on the other hand, increases the level of PGE2 (Hori, et al., 1998) to increase pain sensation. 

Morphine has certain undesirable side effects. Among these are respiratory depression, nausea, and vomiting, depression of the cough reflex, cardiovascular depression and hypotension, smooth muscle contraction (constipation), and histamine release (93). Morphine s onset of action, duration, and low therapeutic indices have prompted a search for a more effective opiate iv anesthetic. Extreme simplification of the complex morphine molecule has resulted in anilido —piperidines, the fentanyl class of extremely potent opiate iv anesthetics (118,119). 

Another agent of this general type is nalmefene (47) Despite their useful characteristics, opiates display tolerance, addiction, abuse, and some toxic side effects Antagonists combat some of these effects, most notably respiratory depression and addiction Nalmefene reputedly has significant oral activity as a narcotic antagonist The synthesis of nalmefine concludes by Wittig olefination of naltrexone (46) to nalmefene (47) This molecular transformation resulted in a significant increase in oral potency as well (141... 

There are a number of side-effects of opiates that are due to their actions on opiate receptors outside the central nervous system. Opiates constrict the pupils by acting on the oculomotor nucleus and cause constipation by activating a maintained contraction of the smooth muscle of the gut which reduces motility. This diminished propulsion coupled with opiates reducing secretion in the gut underlie the anti-diarrhoeal effect. Opiates contract sphincters throughout the gastrointestinal tract. Although these effects are predominantly peripheral in origin there are central contributions as well. Morphine can also release histamine from mast cells and this can produce irritation and broncho-spasm in extreme cases. Opiates have minimal cardiovascular effects at therapeutic doses. 

Acute physiological responses to opiate administration occur rapidly and include constricted pupils, decreased pulse rate, reduced body temperature, slowed respiration rate and impaired reflexes. In addition, there is a marked slowing of the digestive system through an altering of the tonus and motility of the stomach and intestines, allowing for greater water absorption. This last effect is not subject to tolerance, and constipation is a common side effect even for chronic users. Indeed, some report that this is the worst side effect of opiate use. 

Opium and its derivatives have been employed for centuries for the treatment of pain. Morphine was first synthesized in 1805 and has proven to be one of the most effective analgesic agents available [1], Morphine and its analogs are particularly useful because they diminish pain sensation while maintaining consciousness. However, opiates induce severe side-effects including respiratory depression, nausea, bradycardia and constipation and long-term use of opiates can cause addiction [2]. 

A major side-effect of morphine is respiratory depression. Opiates are believed to cause this effect via actions in brainstem nuclei, fi receptor immunoreactivity and mRNA were detected in neurons of the nucleus of the solitary tract, nucleus ambiguous, and parabrachial nucleus. mRNA was detected in the bed nucleus of the stria terminalis which projects to the nucleus of the solitary tract, fi receptor immunoreactivity is found in the nucleus of the solitary tract and dorsal rhizotomy reduced receptor immunoreactivity in the nucleus suggesting a presynaptic localization of the receptor. 

Accurate assessment and history of reported opiate allergies are important. A differentiation between allergy, sensitivity, and side effect needs to be made. 

The common side effects of naltrexone are nansea, headache, and dizziness. In addition, naltrexone has the potential for toxic effects on the liver and should not be used in an alcoholic with cirrhosis or other known liver disease. Because it blocks opiate receptors, patients treated with naltrexone are unable to benefit from the analgesic effects of opiates such as codeine or morphine. Naltrexone may increase serum levels of acamprosate in patients taking both medications. 

Methadone is not without side effects. Although it is less addictive than other opiates, methadone can be abused and requires monitored use. Common side effects include sedation and constipation. Methadone is also safer than other opiates in overdose but does require careful monitoring of respiratory status when an overdose occurs. 

Potential side effects of naltrexone include anxiety, drowsiness, and nausea. In addition, it rarely causes a chemical hepatitis. For this reason, blood testing of liver enzymes should be conducted periodically. If any signs of naltrexone-induced hepatitis appear, it should be discontinued. Furthermore, patients should be advised that they must be totally abstinent from opiates for at least 2 weeks before using naltrexone or it can precipitate severe withdrawal symptoms. 

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