Morphine or hydromorphone: which should be preferred? A systematic review

Abstract

ObjectiveTo systematically review available paediatric literature on comparisons between morphine (Mo) and hydromorphone (Hm), to guide clinicians to rationally use these medications.DesignSystematic review within four databases for all studies published from 1963 to July 2019.SettingAll paediatric settings.EligibilityAll studies comparing Mo to Hm in individuals younger than 21 years.Main outcome measuresThe primary outcome was to compare clinical efficacy and side effects of Mo and Hm. The secondary outcomes were the comparison of pharmacokinetic profiles and the description of predefined Mo to Hm conversion ratios used across the paediatric literature.ResultsAmong 754 abstracts reviewed, 59 full-text articles met inclusion criteria and 24 studies were included in the analysis: 4 studies compared pharmacodynamics of Mo and Hm and 20 studies reported the use of a predefined Mo to Hm conversion ratio. Most studies had a poor methodological quality. Available evidence suggests that, when given intravenously, the equianalgesic ratio of Mo to Hm is 5:1. Intravenous administration with this ratio results in a similar rate of adverse effects, including pruritus and nausea. The epidural administration with a ratio of 10:1 results in more pruritus and urinary retention with Mo than Hm. Pharmacokinetic data were reported in only one study. A wide range of pre-established ratios for different routes of administration were reported, but few were based on evidence.ConclusionCurrent literature does not permit a rational choice between Mo and Hm. A ratio of 5:1 seems adequate for intravenous administration and leads to a similar rate of adverse effects.

The 50% effective dose of hydromorphone and morphine for epidural analgesia in the hemorrhoidectomy: a double-blind, sequential dose-finding study

“…An oral morphine to oral hydromorphone conversion ratio of 8:1 mg/mg is employed for patients experiencing ongoing moderate to severe pain associated with cancer or non-cancer conditions [ 30 ]. Intravenous administration of morphine and hydromorphone have been at around a 5:1 potency ratio [ 8 , 31 , 32 ]. Sviggum et al have found that [ 7 ], the ideal dosage for intrathecal morphine and intrathecal hydromorphone to be given for cesarean-section analgesia is 2:1.…”

Hydromorphone Prescription for Pain in Children—What Place in Clinical Practice?

“…Spénard et al recently published an excellent systematical review that sought to compare the efficacy and safety of hydromorphone and morphine in children ( 69 ). Among 754 abstracts reviewed, they found only four randomized controlled trials that compared the PD of hydromorphone and morphine in children ( 43 , 56 , 57 , 61 ).…”

Morphine and Hydromorphone Effects, Side Effects, and Variability: A Crossover Study in Human Volunteers

“…16,24 When titrated or self-administered to analgesic effect, when evaluated based on analgesia or on analgesia relative to behavioral side effects (mood, sedation, sleep, drug liking), morphine and hydromorphone are generally considered comparable. 24,43 Based on analgesia and more relevant side effects (respiratory depression, nausea, vomiting, itch), hydromorphone is considered to be comparable, 12,16,[44][45][46] or to have some advantage. 4,7,13 Nevertheless, it remains unknown and under discussion whether morphine or hydromorphone is inherently safer or clinically advantageous.…”

“…10,11 Opioid selection for acute pain treatment may be even less data-driven, as the pharmacokinetic differences between morphine and hydromorphone, arguably the two most commonly used opioids for acute pain in the United States, such as for patient- controlled analgesia and emergency department use, are considered to be comparatively minor. 12,13 Numerous clinical outcome studies have evaluated some opioid side effects, and others have attempted to predict risk for respiratory depression for each patient. 4,14 Nevertheless, deep understanding of morphine and hydromorphone clinical pharmacology, including the various clinical effects and their relationship to each other, interindividual variability in these effects, and differences between the opioids remain elusive.…”