Analgesics constipation with

Also discuss his co-dydramol use - it may be short term, and encourage him to discuss the constipation with his GP (as an alternative analgesic may be appropriate). 

Morphi Dex contains morphine sulfate and dextromethorphan in a 1 1 ratio. Double-blind, single-dose analgesic efficacy studies in over 800 patients with post-surgical pain have shown superior analgesic activity for the combination (60 60 mg) than separate doses of the individual components (28,29). In double-bhnd, multiple-dose studies in 321 patients with chronic pain the combination provided satisfactory pain control with a significantly lower mean daily dose of morphine sulfate. Other studies have shown similar responses (28) and an adverse events profile similar to that of a similar dose of morphine sulfate (30). The most common adverse events seen in a multiple-dose, non-placebo-controlled study in 1400 subjects were nausea, dizziness, vomiting, somnolence, confusion, and pruritus. There was a significant trend toward lower incidence of constipation with the combination than with morphine sulfate alone (31,32). 

In a follow-up study of 78 patients with cancer who participated in a crossover, randomized study of transdermal fentanyl (mean final dose 100 pg/hour) and oral morphine for 4 weeks, the incidences of skin reactions and gastrointestinal symptoms were low (56). Other adverse effects reported were breakthrough pain, light-headedness, and diarrhea. In the original randomized study, which lasted 15 days, there was significantly less constipation with fentanyl than with morphine (57). These results suggest that many patients have stable analgesic requirements with transdermal fentanyl up to the time of death, with no need for additional medication. 

To/erdJtce (i.e. a decrea.sed responsiveness) to many of the cffccLS of opioid analgesics occurs with continuous administration. Miosis and constipation are eCfects to which tittle tolerance develops. 

A not uncommon side effect observed with morphine and some of the other narcotic analgesics is constipation due to decreased motility of the gastrointestinal tract. It proved possible to so modify pethidine as to retain the side effect at the expense of analgesic activity. Relief of diarrhea, it will be realized, is a far from trivial indication. Alkylation of the anion from diphenylacetonitrile (95) with ethylene dibromide gives the intermediate, 96. Alkylation of normeperidine (81) with that halide... 

CONSTIPATION The nurse checks the bowel elimination pattern daily because constipation can occur with repeated doses of a narcotic. The nurse keeps a daily record of bowel movements and informs the primary health care provider if constipation appears to be a problem. Most patients should begin taking a stool softener or laxative with the initial dose of a narcotic analgesic. Many patients need to continue taking a laxative as long as the narcotic analgesic is taken. If the patient is constipated despite the use of a stool softener, the primary health care provider may prescribe an enema or another means of relieving constipation. 

The history of this class of analgesics might have stopped there were it not for the manifold ancillary activities shown by that molecule. Although still one of the most widely used agents for treatment of severe pain, morphine is a drug that must be used with caution. Side effects include respiratory depression, induction of constipation, and sometimes marked sedation. The one property that most severely limits use of this drug is its propensity to induce physical dependence in patients subjected to more than casual exposure. 

When prescribing strong opioids as analgesics for severe pain, it is even recommended to combine the treatment with prophylactic use of laxatives to avoid constipation. The effect of opioids on the bowel is to cause almost no movement at all in the bowels and therefore it is unavoidable to use stimulating laxatives sometimes combined with bulk forming preparations. 

Users of fentanyl analogues report that these drugs produce a rapid rush or euphoria that is similar to that felt with heroin, followed by a sedated, dream-like state. As analgesics, they also produce a profound loss of pain sensation and have common unwanted side effects such as sleepiness and constipation. However, because they are so potent, fentanyl analogues can... 

These differences in the behavioural properties of the opioid receptor sub-types are of considerable interest because the clinical use of currently marketed opioid analgesic drugs is limited by their undesirable side-effects, which include respiratory depression, constipation and an abuse or dependence liability. These side-effects have been associated with mu receptor ac-... 

Tramadol is an opioid analgesic, which acts by exerting an opioid effect and through the stimulation of adrenergic and serotonin pathways. Compared with the other opioids, tramadol is less likely to cause the typical opioid side-effects, such as respiratory depression, and constipation. It is also less likely to cause addiction. 

Tolerance. With repeated administration of opioids, their CNS effects can lose intensity (increased tolerance). In the course of therapy, progressively larger doses are needed to achieve the same degree of pain relief Development of tolerance does not involve the peripheral effects, so that persistent constipation during prolonged use may force a discontinuation of analgesic therapy however urgently needed. 

There are some additional choices in patients with refractory arthritis despite the use of NSAIDs or paracetamol (acetaminophen), alone or in combination. Narcotics can be used with little risk of addiction, but with the caveat that they can cause cognitive changes, constipation, urine retention and respiratory depression (see section on analgesics). Codeine... 

Codeine, which is an opium alkaloid is most commonly opiate used as antitussive and more selective for cough centre. Like morphine, it depresses cough centre but is less constipating and abuse liability is low. It is relatively safe drug used in cough along with analgesic property and it s only important adverse effect is constipation. 

Depending on the compound and the effect measured, the degree of tolerance may be as great as 35-fold. Marked tolerance may develop to the analgesic, sedating, and respiratory depressant effects. It is possible to produce respiratory arrest in a nontolerant person with a dose of 60 mg of morphine, whereas in addicts maximally tolerant to opioids as much as 2000 mg of morphine taken over a 2- or 3-hour period may not produce significant respiratory depression. Tolerance also develops to the antidiuretic, emetic, and hypotensive effects but not to the miotic, convulsant, and constipating actions (Table 31-3). 

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... 

The ideal analgesic should obliterate pain and diminish the anxiety associated with it exert a minimal degree of narcosis and stupefaction be free of such undesirable side effects as constipation,... 

The levorotatory isomer of 3-hydroxy-A-methylmorphinan tartrate dihydrate (Levo-dromoran tartrate ) is a more potent analgesic than morphine with an approximately equal margin of safety, but is longer acting and has a lesser constipating action. Contraindications to its use, including the danger of addiction, are similar to those of morphine. 

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