Ambulatory use of high-dose intravenous morphine for severe pain

Opioid titration in cancer pain: a critical review

Initiation of therapy with strong opioids is a challenging phase to obtain the maximum benefit and to gain the patient's compliance. The approach could be different, depending on the clinical situation and type of opioid regimen. Substantially, the need to titrate the dose of strong opioids emerges in different conditions: (a) in opioid-naive patients who require an opioid treatment; (b) in patients no longer responsive to weaker drugs requiring strong opioids; (c) in patients already receiving strong opioids requiring higher doses because of an increase in pain intensity or a new acute pain problem; (d) in patients who are severely suffering and need an intensive as well as rapid intervention, due to previous persistent undertreatment. Whilst there is a vast literature confirming the effectiveness of most opioid drugs for the treatment of chronic pain, there is a lack of information regarding opioid titration. This review assesses the principal titration methods and outcomes regarding the different opioid drugs and their modalities of administration, in different clinical contexts.

Treatment of cancer pain of the head and neck by continuous intravenous infusion of high-dose morphine: report of two cases

Two pain-ridden patients in the terminal stage of a malignancy of the head and neck were treated with high-dose morphine which was administered as a continuous IV infusion along with a hyperalimentation solution using a pump. Good pain relief and a lessening of anxiety were achieved after failure to control pain in spite of the use of the analgesic ladder recommended by the WHO.

Integration of pain management into comprehensive cancer care

Pain management is an integral component of comprehensive cancer care. Designing an effective pain control strategy for the individual patient requires knowledge of the ways in which a patient's cancer, cancer therapy, and pain therapy can interact. Two important aspects of cancer that affect the way in which pain is managed are the cancer's treatability and components of its pathophysiology that themselves do not cause pain (the cancer's "nonpain" pathophysiology). Cancer treatability modifies the need for pain management and the appropriateness of invasive pain procedures. Cancer nonpain pathophysiology can interfere with the oral administration of medications, narrow the patient's therapeutic window for analgesic drugs, limit the effectiveness of psychologic pain therapies, and complicate or preclude invasive pain-relieving procedures. In addition, cancer therapy can interfere with or enhance pain therapy and vice versa. Cancer therapy can interfere with pain therapy by causing pain or by producing other adverse effects. Cancer therapy can enhance pain therapy by reducing the extent of cancer, by acting as a coanalgesic, and by providing intravenous access for parenteral drug administration to patients who require it. Pain therapy can interfere with cancer therapy by increasing or complicating the adverse effects of cancer therapy. Pain therapy can enhance cancer therapy by improving patient performance, and certain palliative surgical procedures may have the ancillary effect of improving organ function. Five case descriptions are presented as illustrations of effective integration of pain management into comprehensive cancer care.

Stability of morphine solutions in plastic syringes determined by reversed-phase ion-pair liquid chromatography

A reversed-phase ion-pair HPLC assay has been developed for quantitating morphine, codeine, apomorphine, and pseudomorphine in aqueous solutions. Using two types of plastic syringes, the effect of light (25 W) and temperature (22 and 3 degrees C) on the stability of morphine, over a 12-week period, has been investigated in the presence and absence of preservative and antioxidant. The leaching of contaminants from the plastic syringes to water stored in them, for a period of up to 12 weeks, has also been investigated. The results indicate that less than 3% of the morphine is degraded in both types of plastic syringes, stored in light at 22 +/- 2 degrees C. The degradation is even less prominent in the dark or at 3 degrees C. Pseudomorphine has been identified as the major degradation product. Using 5% degradation of drug as the criterion for the determination of the shelf-life of morphine, it was found that in one brand of plastic syringes, morphine has a shelf-life of the order of 20 and 33 weeks, in the absence and presence of preservative and antioxidant, respectively. In the other brand of plastic syringe, the drug has a shelf-life of greater than 1 year. Some unidentified leached contaminants have been detected in water stored in both brands of syringes.

Cerebrospinal fluid and plasma pharmacokinetics of morphine infusions in pediatric cancer patients and rhesus monkeys

The cerebrospinal fluid (CSF) and plasma pharmacokinetics of morphine administered as a continuous infusion were studied in pediatric cancer patients and in monkeys with implanted Ommaya reservoirs. In monkeys administered a constant infusion of 0.15 mg morphine sulfate/kg/h, morphine steady-state plasma and CSF concentrations were 84.4 +/- 20.0 ng/ml and 25.3 +/- 4.9 ng/ml, respectively, for a CSF:plasma ratio of 0.30 +/- 0.05. For comparison, the monkeys also received morphine as an intravenous bolus at a dose of 0.45 mg morphine sulfate/kg. The CSF:plasma area under the concentration-time curve (AUC) ratio was 0.40 +/- 0.07, similar to that seen with continuous infusion. Morphine pharmacokinetics were also studied in cancer patients administered long-term infusions of morphine sulfate over a wide dosage range (0.04-31 mg/kg/h). The steady-state plasma concentration of morphine was linearly related to the infusion rate although variability was noted. The average clearance value was 23 ml/min/kg which is at the upper end of the estimates reported for morphine clearance using bolus administration. No evidence for morphine accumulation using long-term administration was observed. A limited number of CSF samples obtained by lumbar puncture showed comparable CSF and plasma concentrations of unbound morphine assuming morphine is approximately 30% bound in human plasma.

Constant morphine infusion for severe sickle cell crisis pain

The use of a constant infusion of intravenous morphine sulfate in a patient with severe sickle cell crisis is described. After several days of poor control with intramuscular and intravenous narcotic injections, adequate analgesia was obtained with the infusion of morphine within two hours of initiation of therapy. No adverse effects were noted. With the advantages provided by an intravenous narcotic infusion, this protocol should be considered as a suitable alternative to conventional methods for providing pain control in patients in sickle cell crisis.

[Prolonged intravenous infusion of morphine. Pharmacokinetic study]

Critically ill patients require optimal pain control without undesirable side-effects. Continuous intravenous morphine infusion is often chosen instead of the conventional intermittent administration. In the present study, the pharmacokinetic characteristics of morphine were studied in five subjects receiving a constant rate intravenous infusion with the attainment of a steady state. The plasma levels were compared with values derived from bolus intravenous administration in five other patients. The concentrations of unchanged morphine were determined in serum using high performance liquid chromatography with an electrochemical detector. The decay of plasma concentrations after a single dose fitted a triexponential function consistent with a three compartment pharmacokinetic model. Postinfusion plasma concentrations fitted a two compartment model. Derived values (mean +/- SEM) of total body clearance were significantly different between groups (p less than 0.05), while mean values of terminal elimination half-life (t 1/2 Kel) were similar. It was concluded that values of total distribution volume were significantly different. The extent of morphine distribution varied more than twofold between the two groups of patients. This was interpreted as a consequence of an important underestimation in the extent of distribution tissues after administration of a single dose.

Continuous intravenous morphine infusions for terminal pain control: a retrospective review

The continuous intravenous infusion of morphine may control terminal cancer pain unrelieved by conventional narcotic therapy. A retrospective review was conducted of the medical records of 79 terminal cancer patients who received a total of 84 intravenous morphine infusions. Data were recorded on morphine dosage, pain control, adverse effects, duration of infusion, and concomitant medication requirements. Infusion duration varied from less than 24 hours to 162 days (median: 7 days). Morphine dosage ranged from 0.5 to 300 mg/h. All patients experienced an improvement in baseline pain control; however, 54 percent required additional medication to enhance analgesia. Serious adverse effects, including marked sedation, hallucinations, diaphoresis, and respiratory depression, were recorded in 14 patients. These effects may be a reason for reducing the dose. Guidelines for the use of continuous intravenous morphine infusions are presented. Accurate pain assessment, morphine dosage calculation, and monitoring of adverse effects are essential to insure the safe and effective use of these infusions.