Morphine and dryness of the mouth

["Terminal" dehydration : Differential diagnosis and body of evidence]

Dehydration in palliative care patients can be associated with increased morbidity and mortality and is nevertheless therapeutically controversial. This article provides an overview of possible causes of dehydration at the end of life and places special emphasis on "terminal" dehydration in the dying. Empirical attitudes of healthcare professionals and persons concerned (patients and relatives) as well as evidence-based findings on "terminal" dehydration are elucidated and the limitations are described. Finally, it is concluded that the appropriate detection of the mode of dehydration (including its underlying pathophysiology) as well as the clinical evaluation of the "reversibility" of the symptoms after fluid therapy, is of central importance in establishing the indications for clinically assisted hydration (CAH).

Laboratory testing for prescription opioids

Opioid analgesic misuse has risen significantly over the past two decades, and these drugs now represent the most commonly abused class of prescription medications. They are a major cause of poisoning deaths in the USA exceeding heroin and cocaine. Laboratory testing plays a role in the detection of opioid misuse and the evaluation of patients with opioid intoxication. Laboratories use both immunoassay and chromatographic methods (e.g., liquid chromatography with mass spectrometry detection), often in combination, to yield high detection sensitivity and drug specificity. Testing methods for opioids originated in the workplace-testing arena and focused on detection of illicit heroin use. Analysis for a wide range of opioids is now required in the context of the prescription opioid epidemic. Testing methods have also been primarily based upon urine screening; however, methods for analyzing alternative samples such as saliva, sweat, and hair are available. Application of testing to monitor prescription opioid drug therapy is an increasingly important use of drug testing, and this area of testing introduces new interpretative challenges. In particular, drug metabolism may transform one clinically available opioid into another. The sensitivity of testing methods also varies considerably across the spectrum of opioid drugs. An understanding of opioid metabolism and method sensitivity towards different opioid drugs is therefore essential to effective use of these tests. Improved testing algorithms and more research into the effective use of drug testing in the clinical setting, particularly in pain medicine and substance abuse, are needed.

Opioid side effects and their treatment in patients with chronic cancer and noncancer pain

Opioids are the foundation of standard analgesic regimens for moderate to severe pain due to life-threatening illnesses such as cancer, and are increasingly employed in chronic noncancer pain of the same severity. Opioids are frequently used for long periods in these populations, sometimes for years. However, side effects are common and may reduce quality of life, or become life threatening, and frequently cause patients to discontinue opioid therapy. Successful opioid therapy dictates that benefits of analgesia outweigh safety concerns. The mechanisms, incidence, and treatment or prevention of commonly reported side effects in chronic pain populations are reviewed, employing best available evidence along with empiric practice. General management strategies include switching opioids ("opioid rotation"), discontinuation of concurrent medications that exacerbate side effects, and symptomatic treatment. In addition, recently recognized adverse events that occur after long-term opioid therapy are discussed. High-quality evidence is lacking for the treatment of most side effects, and the true incidence, underlying mechanisms, and clinical implications of long-term responses to opioid therapy are not yet fully understood.

Pharmacological consequences of long-term morphine treatment in patients with cancer and chronic non-malignant pain

BACKGROUND

In patients with pain of malignant origin morphine may be administered in high and often increasing doses during extended periods of time. In patients with chronic pain of non-malignant origin morphine may be an important remedy, and in these cases the goal is to keep the morphine dose stable. The pharmacokinetic as well as the pharmacodynamic consequences of long-term morphine treatment with special reference to the two most important metabolites of morphine morphine-6-glucuronide (M-6-G) and morphine-3-glucuronide (M-3-G) remain to be settled.

METHODS

Assessments for pain, sedation and other morphine induced side effects were made several times for 19 cancer patients treated with changing doses of oral sustained release (SR) morphine and twice for 17 non-cancer patients treated with stable doses of SR morphine. Blood samples were obtained simultaneously and analysed for contents of morphine, M-3-G and M-6-G by high-performance liquid chromatography (HPLC).

RESULTS

Significant correlations were found between the daily dose of SR morphine and plasma morphine (r = 0.469, p < 0.01), plasma M-6-G (r = 0.677, p < 0.01), and plasma M-3-G ((r = 0.827, p < 0.01), in the cancer patient group, but only between the daily dose of SR morphine and plasma M-3-G (0.662, p < 0.01) and plasma M-6-G (0.571, p < 0.01) in the non-cancer patient group. Normalised M-3-G/M and M-6-G/M ratios for the cancer patient group were independent of duration of treatment and daily dose of SR morphine. Likewise in the non-cancer patient group duration of treatment did not influence the metabolite ratios. Correlations between pain score and plasma morphine, M-6-G and M-6-G/M were weak in the cancer patient as well as in the non-cancer patient group making it impossible to draw any conclusion regarding the potential contributory analgesic effect of M-6-G. Dryness of the mouth was the most frequent adverse effect reported in the non-cancer as well as the cancer patient group. In the latter group patients complaining of dryness of the mouth had significantly higher plasma morphine and M-6-G concentrations than patients who did not suffer from this side effect. This difference persisted (or was close to significance) when excluding patients receiving antidepressants.

CONCLUSION

In the cancer patient group neither dose nor treatment period seems to influence morphine glucuronidation. Likewise in the non-cancer patient group receiving stable doses of morphine duration of treatment does not seem to influence morphine glucuronidation. Dryness of the mouth was positively correlated to high plasma concentrations of morphine and M-6-G.

Pain management principles in the critically ill

This article addresses conventional pharmacologic and nonpharmacologic treatment of pain in patients in ICUs. For the critically ill patient, opioids have been the mainstay of pain control. The optimal choice of opioid and dosing regimen for a specific patient varies depending on factors such as the pharmacokinetics and physicochemical characteristics of an opioid and the body's handling of the opioid, concomitant sedative regimen, potential or actual adverse drug events, and development of tolerance. The clinician must appreciate that favorable pharmacokinetic properties such as a short-elimination half-life do not necessarily translate into clinical advantages in the ICU setting. A variety of medications have been proposed as alternatives or adjuncts to the opioids for pain control that have unique considerations when contemplated for use in the critically ill patient. Most have been relatively unstudied in the ICU setting, and many have limitations with respect to availability of the GI route of administration in patients with questionable GI absorptive function. Nonpharmacologic, complementary therapies are low cost, easy to provide, and safe, and many clinicians can implement them with little difficulty or resources. However, the evidence base for their effectiveness is limited. At present, insufficient research evidence is available to support a broad implementation of nonpharmacologic therapies in ICUs.

Within-subject comparison of the psychopharmacological profiles of oral oxycodone and oral morphine in non-drug-abusing volunteers

RATIONALE

Nonmedical use and abuse of prescription opioids is a significant problem in the USA. Little attention has been paid to assessing the relative psychopharmacological profile (including abuse liability-related effects) of specific prescription opioids.

OBJECTIVES

The aim of this study is to directly compare the psychopharmacological profile of two oral opioids within the same subject.

METHODS

A randomized, placebo-controlled, crossover study was done in which 20 non-drug-abusing volunteers ingested 10 and 20 mg of oxycodone, 30 and 60 mg of morphine, and placebo in separate sessions. Drug doses were equated on an objective measure of opiate effects: miosis. Subjective, psychomotor, reinforcing, and physiological effects of the opioids were assessed.

RESULTS

In general, the two opioids at equimiotic doses produced similar prototypic opiate-like effects and psychomotor impairment of similar magnitude. However, several effects were found only with 20 mg oxycodone. Both drugs produced abuse liability-related subjective effects but also dysphoric effects, particularly with 60 mg morphine. Neither drug at either dose functioned as a reinforcer, as measured by the Multiple Choice Procedure. Relative potency ratios indicated an average oxycodone/morphine [corrected] ratio of 1:3 [corrected]

CONCLUSIONS

The psychopharmacological profile of oxycodone and morphine at equimiotic doses had many similarities; however, differences were found in producing abuse liability-related and dysphoric effects. In the medical community, it is commonly accepted that oral oxycodone is 1.5 to 2 times as potent as oral morphine in producing analgesia; using this ratio, although patients may experience similar degrees of pain relief, those receiving oxycodone may be experiencing stronger and potentially different psychopharmacological effects.

The adverse effects of morphine: a prospective survey of common symptoms during repeated dosing for chronic cancer pain

Little information is available about the incidence, prevalence, or severity of morphine side effects during repeated individualized dosing for chronic cancer pain, although it has been widely used in this way for more than 30 years. The authors' aim was to describe the prevalence of symptoms possibly attributable to morphine side effects in a convenience sample of patients with pain due to advanced cancer. They used a prospective survey of inpatients and outpatients on regularly dosed morphine, with a questionnaire administered weekly for 4 weeks. Forty-two of 56 eligible patients completed at least the first questionnaire, with 30 completing all 4. Dry mouth was the most common symptom reported (point prevalence, 95%); this was often moderate to severe in intensity (57%) and was the most persistent symptom (period prevalence, 20%). Sedation and constipation were frequent (point prevalence, 88%) and was often moderate or severe at some point (55% and 62%, respectively) but had low period prevalence. Nausea was reported by less than half the patients. Myoclonus was common (point prevalence, 83%) but was usually mild and not persistent. Total daily morphine dose had little impact on side-effect patterns. Constipation, dysphoria, myoclonus, nausea, and sedation were more likely to be severe following dose increases. In conclusion, although constipation, nausea, and sedation are well described as side effects of morphine administration, others such as dry mouth and myoclonus appear to be underestimated. Validated patient-based measures of opioid side effects are needed.

Codeine/acetaminophen and hydrocodone/acetaminophen combination tablets for the management of chronic cancer pain in adults: A 23-day, prospective, double-blind, randomized, parallel-group study

BACKGROUND

Analgesics are an essential component of the treatment of cancer-associated pain. Pharmacologic treatment is usually begun with nonopioid analgesics, most frequently acetaminophen. If pain relief is not achieved, the so-called "weak" opioids, such as codeine and hydrocodone, may be used in combination with acetaminophen. Adverse effects (AEs) of the opioids include constipation, somnolence, nausea, and vomiting. Based on the results of a literature search, data comparing the effects of the opioids are lacking.

OBJECTIVE

The purpose of this study was to compare the analgesic efficacy and tolerability of codeine phosphate versus hydrocodone bitartrate in combination with acetaminophen in the relief of cancer-related pain.

METHODS

This 23-day, prospective, double-blind, randomized, parallel-group study was conducted at 3 Colombian centers: University Libre, Social Security Institute, and General Hospital of Medellín, Cali, Colombia. Outpatients with cancer were eligible for the study if they were aged >-18 years and had chronic (duration, >/= 3 months) moderate to severe cancer-related pain (score on 10-cm visual analog scale [VAS], > 3 cm [moderate]; score on a 4-point verbal pain-intensity scale, > 1 [moderate]). Eligible patients were randomly assigned to receive 1 tablet of codeine/acetaminophen (C/A) 30/500 mg or hydrocodone/acetaminophen (H/A) 5/500 mg PO q4h (total daily doses, 150/2500 and 25/2500 mg, respectively) for 23 days. In both groups, if pain intensity was rated as > 3 on the VAS at week 1 or 2, the dosage was doubled. The primary end point was the proportion of patients who achieved pain relief (defined as a score of > 1 on a 5-point verbal rating scale [VRS] (0 = none; 1 = a little; 2 = some; 3 = a lot; and 4 = complete) on study days 1 and 2 and weeks 1, 2, and 3. The secondary end point was the proportion of patients in whom pain was decreased (VAS score, <- 3 cm). AEs were self-reported on a 4-point VRS (0 = absent; 1 = mild; 2 = moderate; and 3 = severe).

RESULTS

Of the 121 patients who participated, 59 received C/A and 62 received H/A. Of the total number of cases, 59% were aged 60 to 89 years, and 55% were men. At baseline, 88% of the patients described their pain intensity as moderate; 12%, severe. Of the patients who received C/A, 58% responded to the initial dosage of 150/2500 mg/d, and 8% of the patients responded to the double dosage; 34% did not experience pain relief. In patients with H/A, pain was reported as absent or mild in 56% of patients at the starting dosage of 25/2500 mg/d; an additional 15% of the patients responded to the double dosage; the remaining 29% of patients did not experience any pain relief. None of the between-group differences in response rates were significant. The most common AEs in the C/A and H/A groups were constipation (36% and 29%, respectively), dizziness (24% and 19%), vomiting (24% and 16%), and dry mouth (15% and 18%), with no significant differences between groups.

CONCLUSION

In this study, efficacy and tolerability were comparable between C/A and H/A over 23 days of treatment in these patients with moderate or severe, chronic, cancer-related pain.

Inadequate salivary flow and poor oral mucosal status in intubated intensive care unit patients

OBJECTIVE

To investigate salivary flow and frequency of oral mucositis in intensive care unit patients compared with patients admitted because of elective coronary artery bypass graft (CABG) surgery. In addition, the pattern of oropharyngeal colonization was investigated in these patients.

DESIGN

Prospective study.

SETTING

Mixed intensive care unit and cardiosurgical ward.

PATIENTS

In this study, 24 ventilated intensive care unit patients and 20 CABG patients were included.

MEASUREMENTS AND MAIN RESULTS

Two dental hygienists examined intensive care unit patients for the presence of periodontal disease and mucositis at admission and subsequently every week during their stay in the intensive care unit. At the same time, stimulated salivary flow and salivary total immunoglobulin A output were measured. Oropharyngeal cultures were obtained as well. CABG patients were examined the day before the operation, 1 day, 1 wk, and 2 wks after the operation. The following results were obtained: a) temporarily reduced postoperative stimulated salivary flow and total salivary immunoglobulin A output in CABG patients and nearly absent stimulated salivary flow in intensive care unit patients; b) oropharyngeal colonization with potentially pathogenic microorganisms in intensive care unit and not in CABG patients; and c) the increase in mucositis index in intensive care unit patients paralleled the increase in potentially pathogenic microorganism oropharyngeal colonization, especially and.

CONCLUSIONS

Absence of adequate salivary flow in intubated intensive care unit patients causes severe xerostomia, which may contribute to the development of mucositis and oropharyngeal colonization with Gram-negative bacteria.

Pain, sedation and morphine metabolism in cancer patients during long-term treatment with sustained-release morphine

BACKGROUND

Morphine-6-glucuronide (M-6-G) and morphine-3-glucuronide (M-3-G) are the two most important metabolites of morphine. Both are pharmacologically active, however, with different effects. M-6-G has been demonstrated capable of inducing anti-nociception and sedation, and M-3-G may induce behavioural excitation and possibly antagonise anti-nociception. Their impact on pharmacodynamics in patients in long-term treatment with oral morphine remains to be settled.

METHODS

Forty-two cancer patients treated with oral sustained-release (SR) morphine were assessed for pain, sedation and other side effects related to morphine treatment. Blood samples were analysed for morphine, M-3-G and M-6-G by high-performance liquid chromatography (HPLC).

RESULTS

Significant correlations were found between the daily dose of SR morphine and plasma morphine (M) (r = 0.535, P < 0.001), plasma M-6-G (r = 0.868, P < 0.001) and plasma M-3-G (r = 0.865, P < 0.001). There was no relationship between plasma morphine, M-6-G, M-6-G/M and pain and sedation scores. Seventy-nine percent of the patients suffered from dryness of the mouth, which was the most frequent side effect observed. Patients in this group had higher plasma morphine and M-6-G concentrations than patients who did not suffer from this side effect.

CONCLUSION

The plasma concentrations of morphine and its metabolites, M-3-G and M-6-G, are significantly correlated to the daily dose of SR morphine. Although M-6-G has analgesic properties, no associations were found between pain and plasma morphine and morphine metabolites. This may be due to the multitudinous factors affecting the dose-effect relationship. Patients with dryness of the mouth had higher concentrations of morphine and M-6-G than patients without this side effect.

Protection by nitric oxide of morphine-induced inhibition of rat submandibular gland function

The effects of morphine, l -arginine (nitric oxide precursor) and l -NAME (nitric oxide synthesis inhibitor ) and their concurrent therapy on rat submandibular secretory function were studied. Pure submandibular saliva was collected intraorally by micro polyethylene cannula from anaesthetized rats using pilocarpine as secretagogue. Single intraperitoneal injection of morphine (6 mg kg(-1)) to rats induced significant (P< 0.01) inhibition of salivary flow rate (28%), total protein (12%) and calcium concentrations (27%). Sodium output was increased (23%, P< 0.01). Single intraperitoneal administration of l -arginine (100 mg kg(-1)) and l -NAME (10 mg kg(-1)) affected salivary gland function. Saliva flow rate was reduced by l -NAME (23%, P< 0.01). The total protein concentration of saliva was increased by l -arginine (21%, P< 0.05) and decreased by l -NAME (19%, P< 0.01). Calcium concentration of saliva was increased by l -arginine (25%, P< 0.01) and reduced by l -NAME (21%, P< 0.01). In combination treatment, l -arginine prevented (P< 0.01) morphine-induced reduction of flow rate while l -NAME potentiated it (P< 0.01). The secretion of total protein and calcium were influenced in a similar trend by concurrent therapy. l -NAME potentiated morphine-induced decrease of total protein and calcium concentrations (P< 0.01) while l -arginine restored (P< 0.01) them to levels close to control and morphine groups respectively. It is concluded that morphine inhibits salivary gland function and nitric oxide (NO) plays a positive role in this system. Also it is confirmed that morphine inhibitory effects on submandibular function are somewhat restored by l -arginine and expanded by l -NAME. The modulatory effect of the l -arginine/NO system on salivary gland function is suggested.

The cognitive and psychomotor effects of morphine in healthy subjects: a randomized controlled trial of repeated (four) oral doses of dextropropoxyphene, morphine, lorazepam and placebo

Ten healthy subjects (four male) of mean age 31 years (range 25-40) took part in a randomized double-blind four-way crossover study to examine the cognitive and psychomotor effects of repeated oral doses of dextropropoxyphene and morphine. Four treatments were compared: dextropropoxyphene napsylate 100 mg, morphine sulphate 10 mg, lorazepam 0.5 mg and placebo. Four doses of each drug were given at 4-h intervals to each subject on four separate study days at least 1 week apart. Cognitive function was assessed using choice reaction time, number vigilance, memory scanning, immediate and delayed word recall, word recognition, picture recognition, critical flicker fusion threshold (CFFT) and subjective measures of alertness, calmness and contentment. Lorazepam impaired the speed of responding on all tasks in which speed was recorded (except digit vigilance) and increased subjective ratings of calmness. Morphine had one major effect, which was to increase the accuracy of responding on the choice reaction time task, at every assessment. Morphine produced some sporadic effects in other tests and an increase in subjective calmness. Dextropropoxyphene impaired performance on choice reaction time and picture recognition. These data show that oral morphine may enhance performance in some measures of cognitive function, whereas dextropropoxyphene (in usual therapeutic doses) seems more likely to cause impairment. Neither opioid has substantial effects on cognition and psychomotor function compared with lorazepam.

Contributing factors to physical symptoms in terminally-ill cancer patients

Prediction of future suffering could improve palliative care. To identify the factors contributing to physical symptoms, a prospective study was performed on two series of hospice inpatients with cancer (n = 150 and n = 200, respectively). Physical symptoms, patients' characteristics, and tumor locations were recorded using a structured protocol on admission and throughout the clinical course. Common symptoms on admission and during the patient's course were pain (65%, 88%), general malaise (58%, 77%), anorexia (57%, 94%), constipation (33%, 71%), dyspnea (33%, 66%), nausea/vomiting (29%, 48%), cough/sputum (29%, 48%), edema (27%, 65%), fever (26%, 70%), abdominal swelling (26%, 42%), and dry mouth (25%, 61%), respectively. The mean number of symptoms was 5.7 +/- 3.0 on admission and 9.6 +/- 3.1 during the course. Factors that contributed to the symptoms were young age (pain, abdominal swelling, dry mouth), performance status (anorexia, general malaise, edema, dyspnea), brain tumor (paralysis), neoplasms of lung/pleura (dyspnea, cough/sputum, death rattle), bone metastasis (pain, paralysis), gastric/pancreas cancer (abdominal swelling), peritoneal metastasis (general malaise, edema, nausea/vomiting, abdominal swelling, dry mouth), opioids (constipation, dry mouth, myoclonus), anticholinergics (dry mouth), and antidopaminergics (myoclonus). Opioid requirement was positively correlated with the presence of bone metastasis, and negatively correlated with age and brain involvement. Additional opioids were frequently used in the final 48 hours in cases with lung/pleura neoplasms. These data suggest that terminal symptoms in cancer patients are determined by local and/or general factors. Clinicians can predict the probability of future symptoms from patients' characteristics, general condition, tumor locations, and medications.

Side effects of morphine administration in cancer patients

According to the World Health Organization (WHO) guidelines, oral morphine is the first choice drug for treating moderate to severe cancer-related pain. The fear of the side effects caused by this drug and the scarce information about prevention and management of these effects are the main reasons for the underuse of morphine. The aim of this paper is to provide a review of the literature on the side effects most frequently present both in the titration phase and during chronic administration of oral morphine and to describe the appropriate treatment.

Xerostomia--a review

Xerostomia, or dry mouth, is a very common symptom amongst the terminally ill and can have profound negative effects on patients' quality of life. Yet, it is often considered trivial and therefore tends to be neglected and ignored. This review examines the pathophysiology, aetiology and methods of assessing xerostomia and its effects and discusses its management, with particular emphasis upon palliation. If xerostomia is managed sensitively and effectively, it is possible to improve patients' comfort and sense of well-being and so improve overall care.

Dehydration and the dying patient

This study investigated the relationship between symptoms and dehydration in 82 subjects with malignant disease. Assessment of respiratory tract secretions, thirst, and dry mouth were made during the dying phase, and serum biochemistry was analyzed. Follow-up data were also collected when the patient died. The median time from entry into the study until death was 2 days. All subjects died without artificial fluid therapy. Analysis showed that over 50% of subjects had a serum osmolality of less than 295 mOsm/kg. Contrary to previous anecdotal evidence, no statistically significant relationship was demonstrated between the level of hydration and respiratory tract secretions. Twenty-eight percent of subjects were able to respond to questions; 87% of these had a dry mouth and 83% felt thirsty. No statistically significant association was found between level of hydration and these symptoms. Artificial hydration to alleviate these symptoms in the dying patient may, therefore, be futile. Further work needs to be carried out regarding the cause and treatment of these symptoms in the dying patient.

Transdermal administration of morphine to healthy subjects

1. Twelve healthy subjects received 10 mg morphine HCl delivered transdermally from an occlusive reservoir applied to a small area of skin, painlessly de-epithelialised by vacuum suction. On a separate occasion, 10 mg morphine HCl was given as an i.v. infusion over 20 min. 2. Venous blood samples were collected serially for 72 h and assayed for morphine, morphine-3-glucuronide (M3G) and morphine-6-glucuronide (M6G) by h.p.l.c. Pupil size, salivation, and central nervous effects (nausea, fatigue, headache, feeling of heaviness and dysphoria/euphoria) were also measured. 3. After transdermal application morphine was absorbed by a first-order process to produce relatively constant plasma drug concentrations over 11 h. The absolute bioavailability of transdermal morphine was 75% (65-85%; 95% CI). The plasma concentrations of both M6G and M3G were lower after transdermal administration than after i.v. infusion, and a considerable delay (of up to 1 h) was observed before the metabolites were detectable. AUC ratios for M3G and M6G relative to morphine were similar after both modes of administration. 4. Non-analgesic effects were less pronounced at the lower plasma drug and metabolite concentrations observed after transdermal delivery than after the i.v. infusion of morphine. 5. Transdermal administration of morphine warrants investigation as an alternative route of morphine delivery.

Elder beliefs: blocks to pain management

Elderly patients have beliefs that, if not incorporated into the pain assessment, can block pain management by interfering with the patient's willingness to acknowledge pain and provide complete and accurate information about the pain experience. Patient beliefs that can block pain management include beliefs about self-concept and the aging process; the patient role; health professionals; pain; and consequences of treatment, including addiction, xerostomia, falls, constipation, and sexual and personality problems. Optimal pain management in the elderly is based on a complete assessment of pain, which may take several patient-nurse visits. Patients tend to reveal more information about health problems with succeeding visits, even if the patient is seen by a different person each time.