Nausea, opioids causing

Opioids cause side effects that limits their use. They include respiratory depression, nausea, vomiting, constipation, a heightened level of blood pressure, urine retention, perspiration, and itching of course, the most dangerous of these is respiratory depression. Opioids cause dependency and addiction. 

Opioids cause nausea and vomiting by stimulating the chemoreceptor trigger zone in the medulla, although tolerance to this effect usually develops within a few days (30). 

The large numbers of opioid receptors in areas of the brainstem such as the solitary tract and adjacent areas are probably related to respiratory effects of opiates, cough suppression and nausea and vomiting. Opiates acting in the brainstem reduce the sensitivity of the respiratory centres to pC02 and this is the most common cause of death from overdose with street use of opiates. 

Morphine is an opioid analgesic that may be used for pain relief in myocardial infarction. However, diamorphine is usually preferred because it causes a lower risk of nausea and hypotension than morphine. 

The adverse reactions include slowing of gastrointestinal propulsion with the ensuing risk of constipation, which can be prevented with lactulose or lactitol. Opioid treatment can also cause nausea and sometimes vomiting. There is also a dependence problem and a risk of respiratory depression. The latter may be a practical problem in anaesthetic practice or in overdose, but rarely in the case of treatment with slowly increased oral doses. The nausea is... 

Diphenoxylate (marketed in combination with atropine as Lomotil in the United States) is chemically related to both analgesic and anticholinergic compounds. It is as effective in the treatment of diarrhea as the opium derivatives, and at the doses usually employed, it has a low incidence of central opioid actions. Diphenoxylate is rapidly metabolized by ester hydrolysis to the biologically active metabolite difenoxylic acid. Lomotil is recommended as adjunctive therapy in the management of diarrhea. It is contraindicated in children under 2 years old and in patients with obstructive jaundice. Adverse reactions often caused by the atropine in the preparation include anorexia, nausea, pruritus, dizziness, and numbness of the extremities. 

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. 

Finally, gastrointestinal distress in the form of nausea and vomiting is quite common with many of the narcotic analgesics. Because of their antiperistaltic action, these drugs can also cause constipation.48 Because this constipating effect can be quite severe, laxatives and stool softeners (see Chapter 27) can be used to prevent opioid-induced constipation in certain people, such as with patients who are at risk for fecal impaction (e.g., people with spinal cord injuries), or with people who are taking opioids for an extended period of time (e.g., patients receiving opioids for treatment of cancer-related pain).36,70... 

Fiction—Opioids often cause prohibitive side effects, like depressed respiration, sedation, and nausea. 

Fentanyl is primarily used alone, but sometimes it is combined with other opiates such as Licodaine, Bupiva-caine, or morphine in epidural administration or in some I Vs. However, one of the more appealing virtues of fentanyl is that, unlike other opioids, it has a very mild effect on the emetic trigger zone of the medulla. For this reason, patients have less nausea and no vomiting when fentanyl is used. With other drugs, such as morphine, this unwanted side effect can be intense. Fentanyl also does not cause the release of histamine, which makes it safer for the cardiovascular system than morphine. 

Hydromorphone has comparable side effects to those produced by morphine use. This is true for sedation, respiratory depression, and constipation, but hydromorphone is associated with less vomiting than morphine. Nausea caused by hydromorphone and other opioids can be minimized by administering the drug along with food and having the patient lie down following administration. 

Pethidine is widely used. There is little difference between the effects of equipotent doses of morphine and pethidine with regard to analgesia, respiratory depression, and nausea and vomiting (but it may delay labour less). AU opioids have the potential to cause respiratory depression of the newborn but this can be reversed with naloxone if necessary. The popular choice of pethidine for analgesia during labour in the UK is not because of any clear pharmacological advantage, but because it remains the only opioid licensed for use by midwives. 

Loperamide (tV 10 h) is structurally similar to diphenoxylate. Its precise mode of action remains obscure but it impairs propulsion of gut contents by effects on intestinal circular and longitudinal muscle that are at least partly due to an action on opioid receptors. Loperamide may cause nausea, vomiting and abdominal cramps. Its potential for abuse appears to be low. 

Nausea and vomiting are frequent adverse effects associated with the use of PCA opioids. Droperidol and tro-pisetron may reduce the incidence and severity of nausea and vomiting caused by morphine (SEDA-19, 84). 

A strategy for controlling pain caused by malignant disease has been outlined and the classic effects that can be associated with opioid administration have been reviewed (6). These include constipation, nausea, sedation, pruritus, urinary retention, myoclonus, and respiratory depression. The latter can be life-threatening. Particular care is needed in opioid-naive individuals, those with compromised respiratory function, and elderly patients. 

When an opioid is used as the sole agent by the epidural or intrathecal route, the results are disappointing, because of unwanted adverse effects, such as pruritus, nausea, vomiting, respiratory depression, and effects on the neonate, caused by significant systemic absorption (SEDA-17, 85). Hypotension and changes in fetal heart rate are not uncommon (SEDA-21, 91). Combinations of opioids (alfentanil, fentanyl, morphine, sufentanil) with local anesthetics (for example bupivacaine) have therefore been suggested to yield better results (SEDA-18, 83). 

The role of tramadol in the treatment of rheumatologi-cal pain has been reviewed (33). Tramadol causes fewer opioid adverse effects for a given level of analgesia compared with traditional opioids. Common adverse effects, such as nausea and dizziness, usually occur only at the beginning of therapy, abate with time, and are further minimized by up-titrating the dosage over several days (34). 

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