Side effects of opiates

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. 

Q4 Constipation can be a troublesome side effect of opiates used for pain relief, for example morphine and codeine. It is also a side effect of some calcium channel blocking agents, antacids containing aluminium compounds and iron salts used in the treatment of anaemia. 

The above results show that it is possible to achieve complete dissociation between cannabimimetic effect and analgetic action.These preliminary results may be of considerable therapeutic value because cannabinoids generally lack many of the side effects of opiates, such as high addiction liability and respiratory depression. 

Opiates Opiates decrease intestinal motility for 2 hours. Side effects of opiates are constipation and CNS depression when combined with tranquilizers, alcohol, and sedatives. Commonly prescribed opiates are ... 

What are the side effects of opiate antidiarrheal medication ... 

Side effects of opiates are constipation and CNS depression when combined with tranquilizers, alcohol, and sedatives. 

The patient s constipation could be caused by dihydrocodeine in the co-dydramol tablets constipation is a common side-effect of opiate analgesics. You could suggest that she try taking paracetamol alone, to see if that cured the constipation. If it did but did not control the arthritic pain sufficiently, you could suggest that she stays on co-dydramol and asks her general practitioner to prescribe a laxative - lactulose may be appropriate - for the constipation. 

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. 

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. 

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. 

As indicated, buprenorphine can offer a quicker option than methadone, with a three-day course reported to be effective for withdrawal from heroin (Cheskin et al. 1994). The side-effects of clonidine which render it unsuitable for community treatment can be manageable in the inpatient setting, although the drug is being superseded by lofexidine where that is available. Controlled studies have found clonidine and lofexidine to be equally effective in alleviating withdrawal symptoms in inpatient detoxification from heroin (Lin et al. 1997) and from methadone (Khan et al. 1997), with lofexidine resulting in less hypotension and fewer adverse effects. Another double-blind controlled study found lofexidine to be broadly as effective as a ten-day methadone detoxification in inpatient opiate withdrawal (Bearn et al. 1996). 

Nausea is a side effect of all opiates. People who take opiates, including methadone, for a long period of time generally develop a tolerance for its nauseating effects. Vomiting, while common with other opiates such as heroin, is actually a rare side effect of methadone. These side effects are due to the stimulation by opiates of the part of the brain called the medulla, which controls nausea and vomiting. 

Another important side effect of all opiates on the central nervous system is respiratory depression. This is caused by an inhibitory effect on the brain stem, which is the part of the brain that controls breathing and other involuntary bodily systems such as heart beat, etc. Like nausea and vomiting, people who take methadone and other opiates normally develop a tolerance to this side effect. However, even people who have taken methadone for a long period of time can develop major respiratory depression. 

Another side effect of methadone is a change in a user s sexual desire and function. One theory is that opiates decrease testosterone levels in both men and women one small study of 29 methadone users found testosterone levels to be decreased by 40%. Methadone also inhibits sexual function by increasing the tone in the... 

Euphoria is a common side effect of most opiates after chronic use, and undoubtedly this effect contributes to their dependence-producing... 

Opioid antagonists (Table 7.4), predominantly naloxone, are used clinically to reverse the effects of opiates in overdose or postoperative sedation. Naltrexone, which has oral bioavailability, is used for the treatment of narcotic addiction and alcohol dependence. As discussed below (Section 2.2.2.1), peripherally selective antagonists are being evaluated for treatment of constipation and other gastrointestinal side effects associated with opioid agonist use. 

Codeine is associated with the same adverse events that may occur with an opiate. Respiratory depression, sedation, nausea, constipation, and pruritus are all common side effects of codeine. These effects are especially pronoimced in the elderly and may be more prolonged in any patient who is slow to clear the drug, such as patients with renal faUure. 

Symptoms resolved within 48h of discontinuing cyclobenzaprine. Serotonin syndrome is a potential complication of initiating cyclobenzaprine, and when adding opiate or antidepressant medications to the regimen. Given its tricyclic properties, serotonin syndrome is a potential side effect of this drug. 

With continuous world-wide misuse of opiates and other drugs taken by self-injection, reports of every conceivable surgical and medical complication continue to proliferate. Most of these have been previously reviewed in Side Effects of Drugs Volume VIII, and it will suffice here to provide references to some further papers. 

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). 

---