Relative analgesic potencies of morphine and hydromorphone in postoperative pain

Opioids in COVID-19: Two Sides of a Coin

Introduction: The treatment of most severe COVID-19 patients included the large-scale use of sedatives and analgesics-possibly in higher doses than usual-which was reported in the literature. The use of drugs that decrease mortality is necessary and opioids are important agents in procedures such as orotracheal intubation. However, these drugs seem to have been overestimated in the COVID-19 pandemic. We performed a review of the PubMed-Medline database to evaluate the use of opioids during this period. The following descriptors were used to enhance the search for papers: "Opioids", "COVID-19," "COVID-19 pandemic," "SARS-CoV-2," "Opioid use disorder," "Opioid dependence" and the names of the drugs used. We also evaluated the distribution of COVID-19 patients in Brazil and the applicability of opioids in our country during the COVID-19 pandemic. Results: Several positive points were found in the use of opioids in the COVID-19 pandemic, for instance, they can be used for analgesia in orotracheal intubation, for chronic pain management, and as coadjutant in the management of acute intensification of pain. However, high doses of opioids might exacerbate the respiratory depression found in COVID-19 patients, their chronic use can trigger opioid tolerance and the higher doses used during the pandemic might result in greater adverse effects. Unfortunately, the pandemic also affected individuals with opioid use disorder, not only those individuals are at higher risk of mortality, hospitalization and need for ventilatory support, but measures taken to decrease the SARS-CoV-2 spread such as social isolation, might negatively affect the treatment for opioid use disorder. In Brazil, only morphine, remifentanil and fentanyl are available in the basic health care system for the treatment of COVID-19 patients. Out of the 5,273,598 opioid units used in this period all over the country, morphine, fentanyl, and remifentanil, accounted for, respectively, 559,270 (10.6%), 4,624,328 (87.6%), and 90,000 (1.8%) units. Many Brazilian regions with high number of confirmed cases of COVID-19 had few units of opioids available, as the Southeast region, with a 0.23 units of opioids per confirmed COVID-19 case, and the South region, with 0.05 units. In the COVID-19 pandemic scenario, positive points related to opioids were mainly the occurrence of analgesia, to facilitate intubation and their use as coadjutants in the management of acute intensification of pain, whereas the negative points were indiscriminate use, the presence of human immunosuppressor response and increased adverse effects due to higher doses of the drug. Conclusion: The importance of rational and individualized use of analgesic hypnotics and sedative anesthetics should be considered at all times, especially in situations of high demand such as the COVID-19 pandemic.

Intravenous patient-controlled analgesia hydromorphone combined with pregabalin for the treatment of postherpetic neuralgia: a multicenter, randomized controlled study

Background

Postherpetic neuralgia (PHN) is the most common complication of acute herpes zoster. The treatment of PHN remains a challenge for clinical pain management. Despite the effectiveness of anticonvulsants, antidepressants, and lidocaine patches in reducing PHN, many patients still face intractable pain disorders. In this randomized controlled study, we evaluated whether hydromorphone through intravenous patient-controlled analgesia (IV PCA) was effective in relieving PHN.

Methods

Patients with PHN were randomly divided into two groups, one group received oral pregabalin with IV normal saline, another group received oral pregabalin with additional IV PCA hydromorphone for two weeks. Efficacy was evaluated at 1, 4, and 12 weeks after the end of the treatments.

Results

Two hundred and one patients were followed up for 12 weeks. After treatment, numerical rating scale (NRS) score of patients in the hydromorphone group was significantly lower than that of the control group, and the difference of NRS scores between the two groups was statistically significant at 4 and 12 weeks after treatment. The frequency of breakthrough pain in the hydromorphone group was significantly lower than that in the control group 1 and 4 weeks after treatment. After treatment, the quality of sleep in the hydromorphone group was significantly improved compared with the control group. The most common adverse reactions in the hydromorphone group were dizziness and nausea, with no significant respiratory depression.

Conclusions

IV PCA hydromorphone combined with oral pregabalin provides superior pain relief in patients with PHN, which is worthy of clinical application and promotion.

An Open-Label Study of Sufentanil Sublingual Tablet 30 Mcg in Patients with Postoperative Pain

Objective

To evaluate sufentanil sublingual tablet 30 mcg (SST 30 mcg) for postoperative pain in an older patient population with comorbidities.

Design

Multicenter, open-label, single-arm study.

Setting

Nine hospitals across the United States.

Subjects

Adults aged ≥40 years who had undergone a surgical procedure.

Methods

Patients with a postoperative pain intensity score ≥4 on an 11-point numeric rating scale (NRS) were allowed to enter the study and receive SST 30 mcg as requested for pain (minimum 60-minute redosing interval) over the 12-hour study period. Efficacy was assessed by patient reports of pain intensity on the NRS and a five-point pain relief scale. Safety was monitored throughout the study; plasma sufentanil concentrations were also measured. The primary efficacy endpoint was the time-weighted summed pain intensity difference (SPID) to baseline over 12 hours (SPID12).

Results

Of the 140 patients enrolled, 69% were American Society of Anesthesiologists Physical Class II or III, 44% had a body mass index (BMI) ≥30 mg/kg², and 29% had hepatic and/or renal impairment. Average age was 54.7 years (SD = 9.9 years), and average baseline pain intensity was 6.2 (SD = 1.9). The most common surgeries were abdominal (59%) and orthopedic (20%). The mean SPID12 was 36.0 (standard error of the mean = 2.2); mean scores were similar, regardless of age, sex, race, and BMI. From baseline, mean pain intensity decreased significantly starting 30 minutes postdose, and mean pain relief increased significantly starting 15 minutes postdose, remaining relatively stable through 12 hours (P < 0.001 at each time point). Four (3%) patients discontinued due to inadequate analgesia, and 45 (32%) patients had one or more adverse events that were considered possibly or probably related to the study drug. Mean plasma sufentanil concentrations were generally similar regardless of age, sex, BMI, or organ impairment status.

Conclusions

SST 30 mcg was effective and well tolerated for the management of moderate-to-severe acute postoperative pain.

Postoperative analgesic effect of hydromorphone in patients undergoing single-port video-assisted thoracoscopic surgery: a randomized controlled trial

Objective: To study the general efficacy of hydromorphone as a systemic analgesic in postoperative pain management following single-port video-assisted thoracoscopic surgery (VATS) and to explore the optimal administration regimen.

Methods: A prospective, randomized, double-blind study was designed and conducted in a tertiary hospital. In total, 157 valid patients undergoing single-port VATS were randomly allocated into three groups. A total of 53 patients received morphine bolus only for postoperative analgesia (Group Mb); 51 patients received a hydromorphone background infusion plus bolus (Group Hb + i), and 53 patients received a hydromorphone bolus only (Group Hb). The primary outcomes were patient-reported static and dynamic pain levels; the secondary outcomes included side effects, sleep quality, and recovery indexes.

Results: Patients in Group Hb + i experienced lower pain intensity (approximately 10 out of 100 on the visual analog scale) in both static pain and dynamic pain in the days following surgery (P<0.01), better sleep quality during the first night only (P=0.002), and a higher satisfaction level than those in the other two groups (P=0.006). A comparison of these variables in Group Mb and Group Hb resulted in no significant differences. Lastly, side effects and recovery indexes remained the same among bolus-only groups and bolus-plus-background-infusion groups.

Conclusion: There is no advantage to administering hydromorphone over morphine using bolus only mode. Within 24 h after surgery, a background infusion should be considered as a part of a standard protocol for patient-controlled intravenous analgesia. At 24 h after surgery, the background infusion should be adjusted in accordance with patient preferences and pain intensity.

Preclinical and Clinical Pharmacology of Hydrocodone for Chronic Pain: A Mini Review

Hydrocodone is one of the most prescribed oral analgesic drugs and it is one of the most abused drugs in general population. It is a mu-opioid agonist predominantly metabolized to the O-demethylated product hydromorphone and to the N-demethylated product norhydrocodone. The purpose of the study is to summarize the preclinical and clinical characteristics of hydrocodone. Pharmacokinetic aspect (terminal half-life, maximum serum concentration, and time to maximum serum concentration) of hydrocodone and the influence of metabolic genetic polymorphism in analgesic response to hydrocodone are also illustrated and commented. Literature on experimental preclinical pharmacology investigating analgesic activity in laboratory animals is furtherly discussed. Moreover, the authors discuss and comment on the updated data regarding safety profile and effectiveness of hydrocodone in the treatment of chronic pain. A bibliographic research was carried out (from February 01, 2018 to August 28, 2018) independently by two researchers (blinded to the authors and initially on results) in the major scientific databases and research engines of peer-reviewed literature on life sciences and biomedical topics, starting from January 1990 to August 2018. Analysis of results of clinical studies suggests that abuse-deterrent extended-release (ER) hydrocodone formulations can be effective and they are well tolerated in the treatment of chronic low back pain. Weaker is the evidence of the analgesic effectiveness of ER hydrocodone on other chronic pain syndromes and non-cancer non-neuropathic chronic pain. In these conditions, hydrocodone showed to have positive effects in non-controlled open studies and needs to be further studied to assess the real strength of results.

WITHDRAWN: Hydromorphone for acute and chronic pain

The original author team were unavailable to complete the update. At September 2013, a new author team is preparing a new protocol for publication in early 2014, with the revised title 'Hydromorphone for cancer pain'.

The editorial group responsible for this previously published document have withdrawn it from publication.

Effectiveness and gastrointestinal tolerability during conversion and titration with once-daily OROS® hydromorphone extended release in opioid-tolerant patients with chronic low back pain

Purpose

To describe the efficacy and safety of hydromorphone extended-release tablets (OROS hydromorphone ER) during dose conversion and titration.

Patients and methods

A total of 459 opioid-tolerant adults with chronic moderate to severe low back pain participated in an open-label, 2- to 4-week conversion/titration phase of a double-blind, placebo-controlled, randomized withdrawal trial, conducted at 70 centers in the United States. Patients were converted to once-daily OROS hydromorphone ER at 75% of the equianalgesic dose of their prior total daily opioid dose (5:1 conversion ratio), and titrated as frequently as every 3 days to a maximum dose of 64 mg/day. The primary outcome measure was change in pain intensity numeric rating scale; additional assessments included the Patient Global Assessment and the Roland–Morris Disability Questionnaire scores. Safety assessments were performed at each visit and consisted of recording and monitoring all adverse events (AEs) and serious AEs.

Results

Mean (standard deviation) final daily dose of OROS hydromorphone ER was 37.5 (17.8) mg. Mean (standard error of the mean [SEM]) numeric rating scale scores decreased from 6.6 (0.1) at screening to 4.3 (0.1) at the final titration visit (mean [SEM] change, −2.3 [0.1], representing a 34.8% reduction). Mean (SEM) change in Patient Global Assessment was −0.6 (0.1), and mean change (SEM) in the Roland–Morris Disability Questionnaire was −2.8 (0.3). Patients achieving a stable dose showed greater improvement than patients who discontinued during titration for each of these measures (P < 0.001). Almost 80% of patients achieving a stable dose (213/268) had a ≥30% reduction in pain. Commonly reported AEs were constipation (15.4%), nausea (11.9%), somnolence (8.7%), headache (7.8%), and vomiting (6.5%); 13.0% discontinued from the study due to AEs.

Conclusion

The majority of opioid-tolerant patients with chronic low back pain were successfully converted to effective doses of OROS hydromorphone ER within 2 to 4 weeks.

Repeat-dose steady-state pharmacokinetic evaluation of once-daily hydromorphone extended-release (OROS(®) hydromorphone ER) in patients with chronic pain

Objective

To characterize the steady-state pharmacokinetic profile of hydromorphone extended-release (ER) in patients with chronic pain taking concomitant medications.

Methods

This open-label repeat-dose study enrolled 22 patients (mean age, 51.4 years; 81.8% female). All patients were receiving at least one concomitant medication; 86.4% were receiving at least two concomitant medications and 81.8% were receiving at least three. Patients receiving a stable dose of an opioid were converted to hydromorphone ER at a 5:1 ratio (morphine equivalent:hydromorphone). The dose was titrated to adequate analgesia over 3–14 days and stabilized between 8–48 mg. Oral morphine immediate-release was permitted for breakthrough pain. Area under the concentration–time curve from 0–24 hours (AUC_0–24), maximum plasma concentration (C_max), trough plasma concentration (C_min), average plasma concentration (C_avg), and degree of fluctuation (100 × [(C_max − C_min) ÷ C_avg]) were calculated based on data from 14 patients.

Results

Dose-normalized to 16 mg, mean pharmacokinetic parameter values were: AUC_0–24, 41.1 ng · h/mL; C_max, 2.6 ng/mL; C_min, 1.1 ng/mL; C_avg, 1.7 ng/mL; and the degree of fluctuation was 99.6%. The pharmacokinetic profile of hydromorphone ER was linear and consistent with dose proportionality. Mean pain intensity difference scores showed statistically significant improvement from 2–21 hours after dosing. Sixteen (72.7%) patients reported at least one adverse event (AE). The most common were constipation (31.8%), headache (22.7%), and vomiting (13.6%). One patient discontinued treatment due to vomiting. No deaths, serious AEs, or unexpected AEs occurred.

Conclusion

These findings replicate and extend the steady-state pharmacokinetic profile of hydromorphone ER, previously characterized in healthy volunteers, to a population of chronic pain patients taking numerous concomitant medications.

Opioid rotation with extended-release opioids: where should we begin?

Opioid rotation is a common and necessary clinical practice in the management of chronic non-cancer pain to improve therapeutic efficacy with the lowest opioid dose. When dose escalations fail to achieve adequate analgesia or are associated with intolerable side effects, a trial of a new opioid should be considered. Much of the scientific rationale of opioid rotation is based on the wide interindividual variability in sensitivity to opioid analgesics and the novel patient response observed when introducing an opioid-tolerant patient to a new opioid. This article discusses patient indicators for opioid rotation, the conversion process between opioid medications, and additional practical considerations for increasing the effectiveness of opioid therapy during a trial of a new opioid. A Patient vignette that demonstrates a step-wise approach to opioid rotation is also presented.

Pharmacokinetics and behavioral effects of liposomal hydromorphone suitable for perioperative use in rhesus macaques

INTRODUCTION

This study aims to evaluate the pharmacokinetic, behavioral, and motor effects of a liposomal preparation of hydromorphone hydrochloride (LE-hydro) in rhesus monkeys. We administered either 2 mg/kg of LE-hydro (n = 8) subcutaneous (s.c.) or 0.1 mg/kg of standard pharmaceutical hydromorphone HCl (hydro) preparation either intravenous (i.v.; n = 4) or s.c. (n = 5).

MATERIALS AND METHODS

Serial blood samples were drawn after injection and analyzed for serum hydro concentration by liquid chromatography/mass spectrometry. Following s.c. injection of 0.1 mg/kg hydro or 2 mg/kg LE-hydro, behavioral evaluations were conducted in groups of rhesus monkeys (n = 10/group) in the presence of a compatible stimulus animal and motor skills were also evaluated (n = 10/group). The motor skills test consisted of removing a food reward (carrot ring) from either a straight peg (simple task) or a curved peg (difficult task).

RESULTS

LE-hydro (MRT(0-INF) = 105.9 h) demonstrated extended-release pharmacokinetics compared to hydro when administered by either i.v. (MRT(0-INF) =1.1 h) or s.c. (MRT(0-INF) =1.3 h) routes. Hydro did not affect motor performance of the simpler task, but the monkeys' performance deteriorated on the more difficult task at 0.5 and 1 h after injection. LE-hydro had no effect on motor skills in either the simpler or more difficult task.

CONCLUSIONS

The results of these studies indicate that LE-hydro has a pharmacokinetic and behavioral side effects profile consistent with an analgesic that could be tested for surgical use in animals. Our studies also expand the use of rhesus monkeys as a translational behavioral pharmacodynamics model for testing extended-release opioid medication.

Opioid rotation: the science and the limitations of the equianalgesic dose table

Opioid rotation refers to a switch from one opioid to another in an effort to improve the response to analgesic therapy or reduce adverse effects. It is a common method to address the problem of poor opioid responsiveness despite optimal dose titration. Guidelines for opioid rotation are empirical and begin with the selection of a safe and reasonably effective starting dose for the new opioid, followed by dose adjustment to optimize the balance between analgesia and side effects. The selection of a starting dose must be based on an estimate of the relative potency between the existing opioid and the new one. Potency, which is defined as the dose required to produce a given effect, differs widely among opioids, and among individuals under varying conditions. To effectively rotate from one opioid to another, the new opioid must be started at a dose that will cause neither toxicity nor abstinence, and will be sufficiently efficacious in that pain is no worse than before the change. The estimate of relative potency used in calculating this starting dose has been codified on "equianalgesic dose tables," which historically have been based on the best science available and have been used with little modification for more than 40 years. These tables, and the clinical protocols used to apply them to opioid rotation, may need revision, however, as the science underlying relative potency evolves. Review of these issues informs the use of opioid rotation in the clinical setting and defines key areas for future research.

A new extended release formulation (OROS) of hydromorphone in the management of pain

Opioid analgesics are essential in the treatment of moderate to severe cancer-related pain. Opioids are also recognized as important in the management of other severe, persistent refractory painful conditions, such as sickle cell disease and arthritis. In the clinical practice of pain management, stable opioid dosing generally depends on achieving maximal analgesia with tolerable side effects typical of opioid analgesics. There is a wide interindividual variability of responsiveness to exogenous opioids both in terms of analgesic efficacy and side effects. Optimizing pain management for the individual patient may require sequential trials of opioid medications until the regimen with the most favorable therapeutic ratio of efficacy to side effects is determined.

Pharmacokinetics of a controlled-release liposome-encapsulated hydromorphone administered to healthy dogs

The purpose of the study was to assess the pharmacokinetics of liposome-encapsulated (DPPC-C) hydromorphone administered intravenously (IV) or subcutaneously (SC) to dogs. A total of eight healthy Beagles aged 12.13 +/- 1.2 months and weighing 11.72 +/- 1.10 kg were used. Dogs randomly received liposome encapsulated hydromorphone, 0.5 mg/kg IV (n = 6), 1.0 mg/kg (n = 6), 2.0 mg/kg (n = 6), or 3.0 mg/kg (n = 7) SC with a 14-28 day washout between trials. Blood was sampled at serial intervals after drug administration. Serum hydromorphone concentrations were measured using liquid chromatography with mass spectrometry. Serum concentrations of hydromorphone decreased rapidly after IV administration of the DPPC-C formulation (half-life = 0.52 h, volume of distribution = 12.47 L/kg, serum clearance = 128.97 mL/min/kg). The half-life of hydromorphone after SC administration of DPPC-C formulation at 1.0, 2.0, and 3.0 mg/kg was 5.22, 31.48, and 24.05 h, respectively. The maximum serum concentration normalized for dose (C(MAX)/D) ranged between 19.41-24.96 ng/mL occurring at 0.18-0.27 h. Serum hydromorphone concentrations fluctuated around 4.0 ng/mL from 6-72 h after 2.0 mg/kg and mean concentrations remained above 4 ng/mL for 96 h after 3.0 mg/kg DPPC-C hydromorphone. Liposome-encapsulated hydromorphone (DPPC-C) administered SC to healthy dogs provided a sustained duration of serum hydromorphone concentrations.

The side effects of morphine and hydromorphone patient-controlled analgesia

BACKGROUND

Despite "clinical lore" among health care providers that treatment with hydromorphone results in improved pain control and fewer adverse side effects, morphine continues to be the first-line medication for postoperative patient-controlled analgesia (PCA). In this study, we compared the efficacy and side-effect profiles of morphine and hydromorphone at concentrations producing equivalent drug effect measured by pain score and miosis.

METHODS

We conducted a prospective, randomized, double-blind trial of 50 general and gynecological surgery patients. Subjects were randomly assigned to receive either morphine (1 mg/mL) or hydromorphone (0.2 mg/mL) via PCA after surgery and were followed for a period of 8 h. The primary outcome was nausea. Secondary outcome variables were pruritus, vomiting, sedation, pain report, pupillary miosis, and patient satisfaction.

RESULTS

The side effect profile was not different between drugs. The incidence of nausea did not differ between morphine and hydromorphone-treated patients (1 h: 44% vs 52%, 8 h: 68% vs 64%), vomiting (1 h: 4% vs 0%, 8 h: 0% vs 4%), or pruritus (1 h: 4% vs 16%, 8 h: 40% vs 40%). There was no difference in the amount of medication required to treat side effects or patient satisfaction. The average ratio of morphine to hydromorphone use was about 7:1. The patients used 10.9+/-6.0 mg morphine versus 1.57+/-1.0 mg hydromorphone after 1 h and 29.0+/-18.0 mg morphine versus 3.9+/-2.5 mg hydromorphone after 8 h. There was no difference between the morphine and hydromorphone groups with respect to postoperative pain scores with movement at 1 h (7.9+/-2.3 vs 7.1+/-2.4) or 8 h (5.7+/-2.8 vs 5.9+/-2.7). There was also no difference in pain at rest or miosis between groups.

CONCLUSIONS

We found no systematic difference between morphine and hydromorphone in opioid-related side effects. Neither was there any difference in efficacy of pain control or patient satisfaction when patients self-titrated to equal drug effect as measured by equianalgesia and pupillary miosis. The choice between morphine and hydromorphone for use in PCA should be guided by patient history, as there may be idiosyncratic reactions to either drug.

Safety and Efficacy of Hydromorphone as an Analgesic Alternative to Morphine in Acute Pain: A Randomized Clinical Trial

STUDY OBJECTIVE

We compare a standard weight-based dose of intravenous hydromorphone (Dilaudid) to a standard weight-based dose of intravenous morphine in adults presenting to the ED with acute severe pain.

METHODS

This was a prospective, randomized, double-blind, clinical trial conducted in an academic medical center. Of the 198 adult patients presenting to the ED with acute severe pain who were randomized to receive either intravenous hydromorphone at 0.015 mg/kg or intravenous morphine at 0.1 mg/kg, 191 patients had sufficient data for analysis. The main outcome measure was the difference between the 2 groups in pain reduction at 30 minutes as measured on a validated numeric rating scale. Adverse effects, pain reduction at 5 minutes and 2 hours postbaseline, and additional analgesics and antiemetics were tracked as secondary outcome measures.

RESULTS

The mean change of pain from baseline to 30 minutes postbaseline in patients allocated to intravenous hydromorphone was -5.5 numeric rating scale units versus -4.1 in patients allocated to intravenous morphine (difference -1.3; 95% confidence interval -2.2 to -0.5). Adverse effects were similar in both groups, with the exception of pruritus, which did not occur in patients receiving hydromorphone (0% versus 6% [difference -6%; 95% confidence interval -11% to -1%]). No patient required naloxone.

CONCLUSION

For the treatment of acute, severe pain in the emergency department, intravenous hydromorphone at 0.015 mg/kg represents a feasible alternative to intravenous morphine at 0.1 mg/kg.

Multicenter, open-label, prospective evaluation of the conversion from previous opioid analgesics to extended-release hydromorphone hydrochloride administered every 24 hours to patients with persistent moderate to severe pain

BACKGROUND

Hydromorphone hydrochloride is a mu-opioid agonist with dose-dependent analgesic properties. Extended-release hydromorphone hydrochloride (ER hydromorphone HCl) capsules have been developed for administration every 24 hours.

OBJECTIVES

This prospective evaluation focused on the first (ie, conversion) phase of 2 identically designed, randomized, controlled studies that compared the safety and efficacy of once-daily ER hydromorphone HCl capsules with immediate-release hydromorphone hydrochloride (IR hydromorphone HCl) tablets administered 4 times daily in the treatment of persistent moderate to severe cancer- and noncancer-related pain.

METHODS

Patients being treated with opioid analgesics for persistent moderate to severe pain were converted to ER hydromorphone HCl using an 8:1 conversion ratio. The dose was titrated to attain an average pain intensity (API) score < or = 4 on a 0- to 10-point numeric rating scale. Supplemental oral IR hydromorphone HCl tablets were used as rescue medication at a dose of one eighth to one sixth of the daily ER hydromorphone HCl dose.

RESULTS

A total of 343 patients (272 [79%] with cancer pain; mean age, 57.8 years) were enrolled and converted to ER hydromorphone HCl from their previous opioids. About half (51%) were women. At baseline, the mean (SD) API score was 5.3 (2.1). Mean (SD) API scores were 4.7 (2.0) after the first 48 hours and 3.4 (2.1) by the end of titration. After 4 to 21 days of titration, 239 (70%) patients reached stabilization defined as a > or = 48-hour period with an API score of < or =4, unchanged ER hydromorphone HCl dose, and < or = 2 rescue doses per day. The stabilized patients had mean (SD) API scores of 2.7 (1.1) at the end of titration. At stabilization, 102 (43%) of 239 patients remained at their initial conversion dose, 129 (54%) had a dose increase, and 8 (3%) had a dose decrease. Frequent (> or =10% of patients) adverse events that occurred within the first 48 hours after conversion and during the entire titration phase were nausea, somnolence, headache, constipation, vomiting, and dizziness.

CONCLUSION

In this prospective evaluation of the conversion and titration phase of 2 randomized, controlled studies, a conversion ratio of 8:1 mg of oral morphine to oral ER hydromorphone HCl was found to be clinically useful in patients with persistent moderate to severe cancer-related or noncancer-related pain.

Hydromorphone

Hydromorphone is a semi-synthetic opioid that has been used widely for acute pain, chronic cancer pain and to a lesser extent, in chronic nonmalignant pain. Its pharmacokinetics and pharmacodynamics have been well studied, including immediate release oral preparations, a variety of slow release oral preparations, as well as administration through intravenous, subcutaneous, epidural, intrathecal and other routes. It is known to be metabolized to analgesically inactive metabolites that have been associated with neuroexcitatory states and other toxicity. There is no evidence that hydromorphone has any greater abuse liability than other opioids. Further research is needed to address remaining areas of uncertainty: equianalgesic ratios; relative risk of toxicity compared with other opioids, its use in nonmalignant pain, and the role of specific hydromorophone metabolites in the development of toxicity, particularly in association with organ failure.

Intraoperative local anesthesia decreases postoperative parenteral opioid requirements for transperitoneal laparoscopic renal and adrenal surgery: a randomized, double-blind, placebo controlled investigation

PURPOSE

To determine if local anesthesia decreases discomfort following laparoscopic upper retroperitoneal surgery, we performed a randomized, double-blind, placebo controlled study in which the port sites and hand assist incision were infiltrated with bupivacaine or placebo prior to surgery.

MATERIALS AND METHODS

A total of 72 patients undergoing transperitoneal laparoscopic renal or adrenal surgery were randomly assigned to the treatment (0.5% bupivacaine) or placebo (0.9% normal saline) arm. Port and hand assist port sites were infiltrated at the outset of the procedure. Postoperative pain and opioid use were measured at consistent intervals.

RESULTS

A total of 37 individuals were treated with placebo (standard laparoscopy [SL] in 15 and hand assisted laparoscopy [HALS] in 22) and 35 were treated with bupivacaine (SL in 16 and HALS in 19). Mean parenteral morphine equivalents use for the placebo vs bupivacaine groups were 29.6 vs 20.0 mg at 12 hours, 50.2 vs 34.5 mg at 24 hours and 57.1 vs 36.6 mg for the total hospital stay (all p <0.05). Parenteral opioid use was decreased in the bupivacaine group in the SL and HALS subgroups with a significant effect at 12 hours in the latter subgroup. On multivariate ANOVA bupivacaine use but not SL vs HALS was associated with decreased parenteral opioid use at all time points (p <0.05).

CONCLUSIONS

At the outset of transperitoneal laparoscopic urological surgery in the upper retroperitoneum, port site and other incision infiltration with long acting local anesthesia decreases postoperative parenteral opioid requirements compared with placebo controls. The effect was seen with SL and HALS and it was greater than any effect of SL vs HALS.

Identification and synthesis of norhydromorphone, and determination of antinociceptive activities in the rat formalin test

The main objective of this paper is to report the identification and synthesis of norhydromorphone, a novel metabolite of hydromorphone, and its antinociceptive activities when tested in the formalin test as compared to other known analgesics. In addition, we are reporting for the first time the lack of antinociceptive activities of hydromorphone-3-glucuronide, dihydromorphine-3-glucuronide and dihydroisomorphine-3-glucuronide in the rat formalin test. Norhydromorphone was isolated and identified as a metabolite of hydromorphone in a cancer patient's urine. An authentic standard of norhydromorphone was synthesized. The identity of norhydromorphone in the urine sample was confirmed by comparing the LC retention time and MS ion fragmentation with the synthetic standard using a liquid chromatographic-mass spectrometric-mass spectrometric (LC-MS-MS) assay. Norhydromorphone was found to be a minor metabolite of hydromorphone in the urine. Additionally, the antinociceptive activities of norhydromorphone, hydromorphone, morphine, dihydromorphine, dihydroisomorphine, hydromorphone-3-glucuronide, dihydromorphine-3-glucuronide and dihydroisomorphine-3-glucuronide were determined in the rat formalin test following intraperitoneal (i.p.) administration. Only limited antinociception was observed and no significant increase in antinociception was detected at the three doses tested. The increased polarity of norhydromorphone as compared to hydromorphone due to the primary piperidine nitrogen may make it less favorable to cross the blood-brain-barrier (BBB), which may be partly responsible. In addition, lower intrinsic antinociceptive activity, which remains to be determined, could also contribute to the low antinociception. Our results also show that hydromorphone was five times as potent as morphine in the formalin test, while dihydromorphine and dihydroisomorphine were equipotent to and 36% as potent as morphine, respectively. Hydromorphone-3-glucuronide, dihydromorphine-3-glucuronide and dihydroisomorphine-3-glucuronide did not exhibit any antinociceptive effect at the doses tested. The results further underscore the importance of a free C3-OH to the analgesic effect of morphine alkaloids.

Effect of fluticasone propionate nasal spray on bioavailability of intranasal hydromorphone hydrochloride in patients with allergic rhinitis

STUDY OBJECTIVE

To investigate the effect of the nasal corticosteroid fluticasone propionate on the bioavailability and pharmacokinetics of single-dose intranasal hydromorphone hydrochloride in patients with allergic rhinitis.

DESIGN

Randomized, three-way, crossover pharmacokinetic study.

SETTING

University clinical research unit.

PATIENTS

Twelve patients with allergic rhinitis.

INTERVENTION

Hydromorphone hydrochloride 2.0 mg was administered by intravenous infusion (treatment A), intranasal spray without allergic rhinitis treatment (treatment B), and intranasal spray after 6 days of fluticasone propionate (treatment C). Blood samples were collected serially from 0-16 hours.

MEASUREMENTS AND MAIN RESULTS

Pharmacokinetic parameters were determined by noncompartmental methods. An analysis of variance (ANOVA) model was used for statistical analysis. Mean (% coefficient of variation) absolute bioavailability of intranasal hydromorphone was 51.9% (28.2) and 46.9% (30.3) in patients with allergic rhinitis with and without treatment with fluticasone propionate, respectively. Mean maximum concentration (Cmax) values were 3.02 and 3.56 ng/ml, respectively. No statistical differences in Cmax and area under the concentration versus time curve were detected between intranasal treatments. Bioavailability values for both intranasal treatments were lower than those in healthy volunteers (57%). Median time to Cmax (Tmax) values were significantly different (p=0.02) for treatments B and C (15 and 30 min, respectively) using rank-transformed Tmax for ANOVA. Adverse effects were consistent with known effects of hydromorphone administered by other routes, with the exception of bad taste after intranasal administration.

CONCLUSION

Hydromorphone was rapidly absorbed after nasal administration, with maximum concentrations occurring for most subjects within 30 minutes. Allergic rhinitis may affect pain management strategies for intranasal hydromorphone, with a delay in onset of action for patients treated with fluticasone propionate.

Bioavailability and Pharmacokinetics of Intranasal Hydromorphone in???Patients Experiencing Vasomotor Rhinitis

BACKGROUND AND OBJECTIVE

Narcotic analgesics such as hydromorphone undergo an extensive first-pass effect resulting in a low systemic bioavailability following oral administration. Alternative dosing routes, such as rectal and intranasal (IN) routes, have been suggested as options for oral or intravenous administration. Rhinitis and pharmacological agents used for treatment are considered factors that could alter the rate and extent of absorption of drugs administered by the nasal route. The purpose of this study was to evaluate the pharmacokinetics of intranasal hydromorphone hydrochloride (HCl) in patients with vasomotor rhinitis.

METHODS

Ten patients completed the randomised, three-way crossover study. During the three treatment periods, a single dose of hydromorphone HCl 2.0mg was administered via intravenous infusion (treatment A) and the intranasal route without (treatment B) or with (treatment C) vasoconstrictor pretreatment for rhinitis. Blood samples were collected serially from 0 to 16 hours. Noncompartmental methods were used to determine pharmacokinetic parameters.

RESULTS

Maximum plasma concentrations were 3.69 and 3.38 mug/L for treatments B and C, respectively. Mean (% coefficient of variation) bioavailability of intranasal hydromorphone was 54.4% (34.8) and 59.8% (22.1) with and without pretreatment, respectively. Pretreatment of rhinitis did not significantly affect the rate or extent of absorption of hydromorphone in this study. There was not a significant difference in bioavailability between treated and untreated rhinitis.

CONCLUSIONS

This study found intranasal administration of hydromorphone in patients experiencing vasomotor rhinitis had acceptable bioavailability and a pharmacokinetic profile comparable to previous studies. These data support further investigation of this single-dose delivery system for clinical use.

Pharmacokinetics and bioavailability of single-dose intranasal hydromorphone hydrochloride in healthy volunteers

We evaluated pharmacokinetics and absolute bioavailability of single doses of hydromorphone hydrochloride after administration of 1.0 and 2.0 mg of intranasal (IN) and 2.0 mg of IV hydromorphone hydrochloride. An open-label, randomized, three-way crossover study was conducted in 24 healthy volunteers (13 men and 11 women). IN doses were delivered as 0.1-mL metered-dose sprays into one or both nostrils for 1.0- and 2.0-mg doses, respectively. Blood samples were taken serially from 0 to 16 h after each dose. Plasma hydromorphone concentrations were determined by liquid chromatography-mass spectrometry-mass spectrometry. Noncompartmental analysis was used to estimate pharmacokinetic variables. Mean hydromorphone bioavailabilities and percent coefficient of variation of 52.4% (22.7) and 57.5% (18.6) were seen after the 1.0- and 2.0-mg IN doses, respectively. Median times to maximum concentration were 20 and 25 min for IN doses. Adverse events included somnolence and dizziness with all routes of administration and a bad taste after IN doses. Dose proportionality for the 1.0- and 2.0-mg IN doses was observed. IN hydromorphone hydrochloride met the minimum requirements for safety and demonstrated rapid nasal drug absorption and clinically relevant bioavailability. Results support further development of this novel hydromorphone hydrochloride nasal spray.

IMPLICATIONS

Pharmacokinetics and bioavailability were determined for two doses of intranasal hydromorphone in healthy volunteers. Rapid, reliable absorption, and predictable pharmacokinetics support the investigation of hydromorphone hydrochloride nasal spray as a therapeutic alternative to oral and IM administration.

A systematic review of hydromorphone in acute and chronic pain

While morphine is historically the gold standard for the management of severe cancer pain, some patients either do not achieve adequate analgesia, or suffer intolerable side effects from this drug. For these patients, alternatives such as hydromorphone are recommended. This review explores the evidence for the efficacy of hydromorphone in the management of pain. A systematic search, from 1966 to 2000, of published and unpublished randomized trials that involved the administration of hydromorphone for both acute and chronic pain conditions in adults and children, was conducted. Forty-three studies were included in the review; 11 involved chronic cancer pain and 32 acute pain. Approximately half the studies received a low quality score. In addition, the heterogeneity of the studies precluded combination of data and results. Overall, hydromorphone appears to be a potent analgesic. The limited number of studies available suggests that there is little difference between hydromorphone and other opioids in terms of analgesic efficacy, adverse effect profile and patient preference. However, most studies involved small numbers of patients and wide ranges in equianalgesic dose ratios, making it difficult to determine real differences between interventions.

Implantable devices for pain control: spinal cord stimulation and intrathecal therapies

Untreated chronic pain is costly to society and to the individual suffering from it. The treatment of chronic pain, a multidimensional disease, should rely on the expertise of varying health care providers and should focus not only on the neurobiological mechanisms of the process but also on the psychosocial aspects of the disease. Implantable devices are costly and invasive, and such efficacious therapies should be used only when more conservative and less costly therapies have failed to provide relief of pain and suffering. Spinal cord stimulation provides neuromodulation of neuropathic, but not nociceptive, pain signals and when used for appropriate indications in the right individuals provides approximately 60-80% long-term pain relief in 60-80% of patients trialled for efficacy. Intrathecal therapies with opioids such as morphine, fentanyl, sufentanil or meperidine--or non-opioids such as clonidine or bupivacaine--provide analgesia in patients with nociceptive or neuropathic pain syndromes. Baclofen, intrathecally, provides profound relief of muscle spasticity due to multiple sclerosis, spinal cord injuries, brain injuries or cerebral palsy.

Hydromorphone metabolites: isolation and identification from pooled urine samples of a cancer patient

1. Hydromorphone-3-glucuronide, dihydromorphine, dihydroisomorphine, dihydromorphine-3-glucuronide and dihydroisomorphine-3-glucuronide were isolated from a cancer patient's urine and identified as metabolites of hydromorphone by comparison with synthetic standards using LC/MS/MS with gradient elution. 2. The relative urinary recovery of dihydroisomorphine-3-glucuronide was estimated to be 17-fold higher than previously reported. 3. Three new metabolites, including hydromorphone-3-sulphate, norhydromorphone and nordihydroisomorphine, were tentatively identified.

Hydromorphone for acute and chronic pain

BACKGROUND

While morphine is the gold standard for the management of severe cancer pain, some patients either do not achieve adequate analgesia, or suffer intolerable morphine-related toxicity. For these patients alternatives such as hydromorphone are recommended. However, there appear to be gaps in our understanding of the efficacy and potency of hydromorphone.

OBJECTIVES

This review explores and assesses the evidence for the efficacy of hydromorphone in the management of pain.

SEARCH STRATEGY

Randomised trials which included hydromorphone were sought using electronic databases and by handsearching relevant journals. Date of the most recent search: February 2000.

SELECTION CRITERIA

RCTs which involved the administration of hydromorphone, for both acute and chronic pain conditions, in adults and children, were included.

DATA COLLECTION AND ANALYSIS

A data extraction form was designed for the purpose of the review. The validity of each trial for inclusion was assessed using criteria described in the Cochrane Handbook. A grade was allocated to each study on the basis of allocation concealment. A checklist was used to assess blinding.

MAIN RESULTS

Forty three studies (2725 subjects) were included in the review. Approximately half of these studies received a low quality score. In addition, the heterogeneity of the studies precluded combination of data and results. A meta-analysis was therefore not possible. Of the 43 included studies, 11 (645 subjects) involved chronic pain conditions (all cancer) and 32 (2080 subjects) acute pain. Three studies were placebo-controlled. Of the remainder, hydromorphone was compared with other opioids (morphine, fentanyl, sufentanyl, meperidine, oxycodone, diamorphine), bupivicaine and with itself, using different formulations. The routes of administration included intravenous, oral, spinal, intramuscular and subcutaneous. Overall, hydromorphone appears to be a potent analgesic. The limited number of studies available suggest that there is little difference between morphine and hydromorphone in terms of analgesic efficacy, adverse effect profile and patient preference. However, as most studies involved small numbers of patients, it is difficult to determine real differences between both drugs. In the context of both acute and chronic pain, the issue of equi-analgesic ratios between morphine and hydromorphone was not resolved.

REVIEWER'S CONCLUSIONS

The studies included in this review were varied in terms of quality and methodology. However, the majority demonstrated that hydromorphone is a potent analgesic, that the clinical effects of hydromorphone appear to be dose-related, and that the adverse effect profile of hydromorphone is similar to that of other mu opioid receptor agonists.

Equianalgesic dose ratios for opioids. a critical review and proposals for long-term dosing

Clinicians involved in the opioid pharmacotherapy of cancer-related pain should be acquainted with a variety of opioids and be skilled in the selection of doses when the type of opioid or route of administration needs changing. The optimal dose should avoid under-dosing or overdosing, both associated with negative outcomes for the patient. Although equianalgesic dose tables are generally used to determine the new doses in these circumstances, the evidence to support the ratios indicated in these tables largely refers to the context of single dose administration. The applicability of these ratios to the setting of chronic opioid administration has been questioned. A systematic search of published literature from 1966 to September 1999 was conducted to critically appraise the emerging evidence on equianalgesic dose ratios derived from studies of chronic opioid administration. There were six major findings: 1) there exists a general paucity of data related to long-term dosing and studies are heterogeneous in nature; 2) the ratios exhibit extremely wide ranges; 3) methadone is more potent than previously appreciated; 4) the ratios related to methadone are highly correlated with the dose of the previous opioid; 5) the ratio may change according to the direction the opioid switch; and 6) discrepancies exist with respect to both oxycodone and fentanyl. Overall, these findings have important clinical implications for clinicians and warrant consideration in the potential revision of current tables. The complexity of the clinical context in which many switches occur must be recognized and also appreciated in the design of future studies.

The pharmacological basis of contemporary pain management

Pain management has become an increasingly well researched area in medicine over recent years, and there have been advances in a number of areas. While opioids remain an integral part of pain-management strategies, there is now an emphasis on the use of adjuvant drugs, such as paracetamol and anti-inflammatory agents, which through physiological or pharmacological synergism, both enhance pain control and reduce opioid use. The management of neuropathic pain continues to be a challenge. Anti-epileptics and antidepressants, together with clonidine and ketamine, provide the foundations for treatment. Another area of interest has been the widespread use of patient-controlled analgesia and the administration of some drugs, especially opioids, by means other than traditional oral and parenteral routes. The number of new drugs that have reached the stage of clinical trials has been small, yet they offer exciting possibilities. The epibatidine analogue ABT-594 and zinconitide both offer novel approaches to the management of neuropathic pain states, while selective cyclo-oxygenase-2 inhibitors and nitroaspirins may see advances in the management of nociceptive pain states.

Clinical analgesic equivalence for morphine and hydromorphone with prolonged PCA

A morphine to hydromorphone equivalence ratio of 7:1 has become the accepted standard, but evidence supporting it comes from single dose studies performed before the advent of patient controlled analgesia (PCA). We compared morphine and hydromorphone use with PCA in bone marrow transplantation patients who required opioids for the control of severe oral mucositis over several days or weeks. An exploratory analysis of clinical records from 102 patients (981 patient days) who used PCA opioids for varying periods of up to 50 days suggested a morphine to hydromorphone use ratio of 3:1. To clarify this observation, we studied a subset of patients under matched conditions. During a 7 day window in which mean oral mucositis severity did not vary across drug use groups and pain scores did not vary over time, patients in both groups gave equal pain relief satisfaction scores. Thirty-six patients who used morphine and 21 who used hydromorphone contributed data on pain, satisfaction with pain control, and drug consumption. We observed an average morphine/hydromorphone ratio of 3:1. This differs markedly from historical single dose studies used in published dose equivalency recommendations implying that other equivalency ratios in clinical use may be inappropriate.

Patient-controlled analgesia for mucositis pain in children: a three-period crossover study comparing morphine and hydromorphone

OBJECTIVES

(1) To test the safety and efficacy of a clinical protocol for administering opioid by using patient-controlled analgesia (PCA) for the management of mucositis pain in children after bone marrow transplantation, (2) to compare the efficacy, side-effect profile, and potency ratio of morphine with those of hydromorphone by using PCA as the method of opioid administration, and (3) to obtain pharmacokinetic data on hydromorphone and morphine in this population of children.

METHODS

In this double-blind, three-period crossover study, patients were randomly assigned to receive either morphine (group 1) or hydromorphone (group 2) initially by means of PCA on days 1, 2, and 3 (period 1), to be followed on days 4, 5, and 6 (period 2) with the alternative opioid, followed by the opioid used at the commencement of the study on days 7, 8, and 9 (period 3). A clinical protocol for calculating the PCA commencement opioid dose and subsequent opioid-dose escalation was tested by measures of safety and efficacy. Measures of pain intensity and opioid side effects were made during the three periods. On the last study day (day 10), patients received a continuous infusion of opioid derived from the previous 24-hour PCA opioid requirement, and blood specimens were collected and stored for subsequent opioid analysis.

RESULTS

Ten patients were enrolled in this study. Rapid escalation in opioid requirement commonly occurred at the commencement of PCA, followed by a variable plateau phase and then deescalation of opioid requirement after mucositis resolution. The measures demonstrated the safety and efficacy of the clinical protocol. In the concentrations used, there was no statistical difference between the mean daily pain, sedation, nausea and vomiting, and pruritus scores for both opioids (Friedman test). The analysis of variance of the log-total opioid doses per patient during periods 1, 2, and 3 indicated that patients used 27% more hydromorphone than expected from its presumed 7:1 ratio relative to morphine potency used in the PCA infusions. The mean plasma hydromorphone concentration was 4.7 ng/ml (range, 1.9 to 8.9 ng/ml), and the mean clearance was 51.7 ml/min per kilogram of body weight (range, 28.6 to 98.2 ml/min per kilogram). The mean plasma morphine, morphine-6-glucuronide, and morphine-3-glucuronide concentrations were 40.0 ng/ml (range, 15 to 62.5), 168.2 ng/ml (range, 54.4 to 231.9), and 391.0 ng/ml (range, 149.4 to 921.7), respectively. The mean morphine clearance was 34.3 ml/min per kilogram of body weight (range, 19.3 to 58.3). The mean molar ratios of morphine-6-glucuronide/morphine, morphine-3-glucoronide/morphine, and morphine-3-glucuronide/morphine-6-glucuronide were 2.48 (range, 1.4 to 3.3), 5.82 (range, 3.4 to 9.1), and 2.46 (range, 1.1 to 3.3), respectively.

CONCLUSIONS

The safety and efficacy of a clinical protocol for the administration of opioids by means of PCA for mucositis pain after bone marrow transplantation was demonstrated. In this small study, hydromorphone was not superior to morphine in terms of analgesia or the side-effect profile: a larger study would be needed to show a difference. The clearances of hydromorphone and morphine in the children studied were generally greater than those previously recorded, but this finding may be related to disease or treatment variables. Apart from clearance, the morphine pharmacokinetics in the study population were similar to those previously recorded. Hydromorphone may be less potent in this population of children than indicated by adult equipotency tables.

A multidimensional comparison of morphine and hydromorphone patient-controlled analgesia

Although patient-controlled analgesia (PCA) pumps have been in use for more than a decade, the optimal PCA analgesic has yet to be identified. Many drugs are used; however, morphine remains the "gold standard" of opioid analgesics worldwide. The present study evaluated morphine and hydromorphone (Dilaudid) PCA with respect to analgesic efficacy, side effects, mood, and cognitive function. Sixty-one opioid naive patients undergoing lower abdominal surgery participated in the double-blind protocol. Verbal rating scores, use of medication, and side effects for the two medications were recorded. Cognitive functioning was assessed by computation of Digit Symbol and Trails Making B Tests. Self-reported affective state (mood) was measured by Profile of Mood States (POMS) inventory. Both medications provided adequate analgesia without a difference in side effects. Cognitive performance was poorer in the hydromorphone group (P < 0.05). Patients receiving hydromorphone reported less anger/hostility (P < 0.01) and generally better mood elevations on the other subscales than those receiving morphine. A similar incidence of side effects and dose medication can be anticipated with morphine and hydromorphone. When considering cognitive effects, morphine had less adverse consequences, while hydromorphone appeared to result in improved mood. We conclude that hydromorphone may provide a suitable alternative to morphine.

Comparison of hydromorphone and meperidine for ureteral colic

OBJECTIVE

To compare the efficacies of meperidine and hydromorphone in the treatment for ureteral colic in the emergency department (ED).

METHODS

A prospective, double-blind, randomized clinical trial was conducted over six months at a tertiary referral center with 93,000 annual ED visits. Seventy-three patients completed the study. The patients received either 1 mg of hydromorphone or 50 mg of meperidine IV at t = 0. Pain intensity was determined using a 10-cm visual analog scale at t = 0, 15, 30, 60, and 120 minutes. A second dose of the study drug could be given between t = 15 and t = 120 minutes when the clinician believed the initial dose was ineffective. Patients requiring more than one additional dose of analgesia were treated as nonresponders and were removed from the study.

RESULTS

Thirty-six patients received hydromorphone and 37 received meperidine. The initial pain intensities (hydromorphone group = 8.4 +/- 1.5; meperidine group = 8.5 +/- 2.1), age distributions, sex distributions, and side effects of the two groups were comparable. Pain relief was better (p < 0.05) with hydromorphone at t = 15, 30, 60, and 120 minutes. The hydromorphone group required rescue analgesia less often (31% vs 68%, p < 0.01), had fewer IV pyelographies (IVPs) (28% vs 54%, p < 0.05), and had a lower proportion of hospital admissions (25% vs 49%, p = 0.08).

CONCLUSIONS

For the fixed doses used in this study, the adult ureteral colic patients receiving hydromorphone achieved more pain relief, required less rescue medication, underwent fewer IVPs, and avoided hospital admission more frequently than did those receiving meperidine.

Comparative clinical efficacy and safety of immediate release and controlled release hydromorphone for chronic severe cancer pain

BACKGROUND

The short elimination half-life of hydromorphone necessitates 4-hourly dosing to maintain optimal levels of analgesia in patients with chronic cancer pain. The purpose of this study was to compare the clinical efficacy and safety of controlled release hydromorphone administered every 12 hours and immediate release hydromorphone administered every 4 hours in patients with chronic severe cancer pain.

METHODS

Forty-eight patients with stable chronic severe cancer pain were randomized, in a double-masked crossover study, to controlled release hydromorphone every 12 hours or immediate release hydromorphone every 4 hours for 7 days each. Pain intensity was assessed using a visual analog scale (VAS) and the Present Pain Intensity Index of the McGill Pain Questionnaire. Nausea and sedation were also assessed using a VAS. Assessments were made by the patient four times a day at 7:00 a.m., 11:00 a.m., 3:00 p.m., and 7:00 p.m. Use of rescue hydromorphone also was recorded by the patient.

RESULTS

Forty-five patients completed the study (26 women, 19 men; mean age, 57.1 +/- 13.6 years) and received a mean daily dose of 76 +/- 133 mg (range, 6-768 mg). There were no significant differences between controlled release hydromorphone and immediate release hydromorphone in overall VAS pain intensity scores (19 +/- 14 vs. 20 +/- 14 mm), ordinal pain intensity scores (1.2 +/- 0.8 vs. 1.2 +/- 0.8) and pain scores by day of treatment or time of day. The daily rescue analgesic consumption during controlled release hydromorphone and immediate release hydromorphone did not differ significantly overall (1.1 +/- 1.1 vs. 1.0 +/- 1.1 doses per day) or with respect to time of day. There were no significant differences in overall VAS sedation scores (18 +/- 18 mm vs. 19 +/- 18 mm) and in overall mean VAS nausea scores (12 +/- 15 mm vs. 11 +/- 14 mm) between controlled release hydromorphone and immediate release hydromorphone.

CONCLUSIONS

Controlled release hydromorphone administered every 12 hours is as effective as immediate release hydromorphone administered every 4 hours in the management of patients with chronic severe cancer pain. The benefits of controlled release hydromorphone lie in the convenience of its capsule formulation, which can be sprinkled on soft food, and its 12-hour duration of action, which allows patients uninterrupted sleep and improved compliance.

Failure of epidural opioid to control cancer pain in a patient previously treated with massive doses of intravenous opioid

A patient with disseminated cancer pain failed to obtain pain relief despite the intravenous infusion of hydromorphone at a rate equivalent to over 7 g of morphine/day. Temporary pain relief occurred with an epidural injection of the local anesthetic lidocaine. Subsequently, the patient failed to obtain pain relief with a dose of epidural hydromorphone equivalent to approximately 3 g of morphine epidurally/day. At this time a syndrome of agitation, sweating, tachycardia and severe muscle cramps developed in the lower half of the body. After eliminating the possibility of spinal cord compression by diagnostic CT scanning, the patient was treated by reducing the dose of hydromorphone and adding local anesthetic, which provided pain relief but did not eliminate the severe muscle spasms and other symptoms. The addition of oral clonidine followed by clonidine dermal patch rapidly and completely eliminated the other symptoms, suggesting that the response was due to too rapid withdrawal of opioid. Maintenance of pain relief required the simultaneous administration of epidural bupivacaine and hydromorphone. A low-dose infusion of epidural bupivacaine was continued for more than 3 weeks and during this entire period the patient showed no evidence of motor or sympathetic block.

Pharmacokinetics of hydromorphone after intravenous, peroral and rectal administration to human subjects

The pharmacokinetic properties of hydromorphone in healthy young male subjects were studied after i.v., peroral, and rectal administration. After i.v. administration the following pharmacokinetic parameters were found: elimination half-life 2.36 +/- 0.5 h, hepatic extraction ratio 0.51, apparent volume of distribution 2.9 +/- 1.3 L kg-1 and volume of central compartment 0.23 +/- 0.2 L kg-1. The absolute bioavailability after peroral administration was 50.7 +/- 29.8 per cent, and that after rectal administration was 33 +/- 22 per cent.