Sugar Solution Analgesia: The Effects of Glucose on Expressed Mu Opioid Receptors

Pain influences food preference and food-related memory by activating the basolateral amygdala in rats

The amygdala has been demonstrated to contribute to pain-related behavior and food preference. Here, the effect of pain on food preference and food-matched visual-cue memory, in the presence or absence of a basolateral amygdala (BLA) lesion, has been evaluated using a novel innovative apparatus and protocol. Forty adult male Wistar rats were randomly divided into five groups (n = 8) as follows: control, pain, ibuprofen + pain, BLA lesion, BLA lesion + pain groups. Bilateral lesions of the BLA were produced by passing a current of 1.5 mA for 7 s. Pain was induced on the right hind paw of the rats by sub-plantar injection of 50 μl of 2.5% formalin. The animals were encountered with four different meals including wholemeal, wholemeal + sugar, white flour, and biscuit. Each test session consisted of six trials with inter-trial intervals of 15 min. The number of visits to each meal zone and port, the amount of time spent in each food zone and port, traveled distance in each food zone, food consumption per each visit and the total food consumption were recorded. The control group showed a high biscuit preference and low white flour preference. Rats suffering BLA lesion and rats in the BLA lesion + pain group exhibited a shifted preference curve. They had a bias toward eating wholemeal + sugar rather than white flour and biscuit. This group also showed an impaired spatial memory. In conclusion, our findings suggest that the BLA may be involved in pain-induced food preference and food-matched visual-cue memory.

Behavioral Responses to Sucrose as an Indicator of Positive Hedonic Response Across the First Six Months of Infancy

Behavioral responses to sucrose provide an index of positive hedonic response in newborns. In 118 infants, the current study used repeated assessments to explore behavioral responses to sucrose solutions (24%/50% sucrose) compared to water across the first six months of infancy. Lip smacking and bringing fingers to mouth are more likely to occur in response to 24% sucrose relative to water. Tongue protrusions are also more likely to occur for 50% sucrose relative to water. Behavioral responses to sucrose may provide an index of positive hedonic response and could be used to investigate individual differences in the first six months of infancy.

Topical anesthesia or oral dextrose for the relief of pain in screening for retinopathy of prematurity: a randomized controlled double-blinded trial

OBJECTIVE

Compare efficacy of 0.5% proparacaine eye drops and oral 25% dextrose in reducing pain during screening for retinopathy of prematurity (ROP).

PATIENTS AND METHODS

Double-blinded randomized controlled trial. Twenty eligible babies were randomized. Group I received 0.5% proparacaine eye drops at first ROP screening, while Group II received 25% dextrose orally. At second examination, babies received no intervention. Pain was assessed using Premature Infant Pain Profile (PIPP) score.

RESULTS

The mean ( ± SD) PIPP during procedure in Group I were 15.5 ± 2.06 and 14 ± 2.4 at first and second screening (p = 0.259). The mean ( ± SD) PIPP in Group II were 14.2 ± 1. 8 and 14.9 ± 2.5 at the first and second screening (p = 0.428). Differences were not statistically significant. The PIPP scores of Group I and Group II at the first screening were also not significantly different (p = 0.165).

CONCLUSION

ROP screening causes moderate to severe pain and neither proparacaine nor dextrose is an effective analgesic.

The relationship between pain and eating among overweight and obese individuals with osteoarthritis: an ecological momentary study

The relationship between pain and overweight/obesity is bidirectional – excess weight can cause pain, yet eating food high in calories, fat and sugar has been shown to alleviate pain. It appears likely that overweight/obese individuals may turn to these types of foods when they experience pain, leading to weight gain; however, this phenomenon has not been examined to date. The authors of this study set out to elucidate the relationship between pain and food intake in obese and overweight patients with osteoarthritis.

BACKGROUND:

Osteoarthritis (OA) patients who are overweight or obese report higher levels of pain compared with their normal-weight OA counterparts. Evidence suggests that overweight or obese OA patients also experience pain relief from eating foods high in calories, fat or sugar. Eating to alleviate pain may be problematic because it can lead to additional weight gain, which may contribute to heightened pain.

OBJECTIVES:

To investigate the relationship between pain and food intake using ecological momentary assessments in a sample of 71 over-weight and obese OA patients.

METHODS:

Participants completed two consecutive days of diary entries in which they recorded their levels of pain, mood and food intake throughout the day. Data were analyzed using generalized estimating equations that modelled pain as a predictor of calorie, fat and sugar intake. All models were adjusted for sex, body mass index, negative mood, time and treatment history.

RESULTS:

Pain significantly predicted calorie (Z=2.57; P=0.01) and fat intake (Z=1.99; P=0.05).

CONCLUSIONS:

Using ecological momentary assessments as a novel approach, the present study provides preliminary data supporting a relationship between pain and food intake among overweight and obese OA patients. Continued advances in our understanding of the relationship between pain and eating behaviour may help to optimize intervention strategies for these patients.

Sweet-tasting solutions for needle-related procedural pain in infants one month to one year of age

BACKGROUND

Administration of oral sucrose or glucose with and without non-nutritive sucking is frequently used as a non-pharmacological intervention for needle-related procedural pain relief in infants.

OBJECTIVES

To determine the effectiveness of sweet-tasting solutions for needle-related procedural pain in infants one month to one year of age compared with no treatment, placebo, other sweet-tasting solutions, or pharmacological or other non-pharmacological pain-relieving methods.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2012); MEDLINE via Ovid (1966 to 2012); CINAHL via OVID (1982 to 2012). The World Health Organization International Clinical Trials Registry Platform was also searched for any ongoing trials. Clinical trial registries, conference proceedings and references for randomised controlled trials (RCTs) were also searched. An updated search was run to capture any new publications before finalising the review in April 2012 and no new included studies were identified. Two review authors (MK & JF) independently abstracted data and assessed quality using a standard form. Authors have been contacted for missing data.

SELECTION CRITERIA

Randomised-controlled trials using a sweet-tasting solution to treat pain in healthy term infants (gestational age 37 weeks and over), between one month and 12 months of age who required needle-related procedures. These procedures included but were not limited to: subcutaneous or intramuscular injections, venepuncture, and heel lance. Studies in which the painful procedure was circumcision, lumbar puncture or supra-pubic bladder aspiration were not included as they are more severe and painful than needle-related procedures. Control conditions included no treatment or placebo (water) or any other identical intervention (same appearance and consistency) without active ingredient, another sweet-tasting solution, a pharmacological pain-relieving method (e.g. paracetamol, topical anaesthetic cream), non-pharmacological pain-relieving method (e.g. distraction method, non-nutritive sucking).

DATA COLLECTION AND ANALYSIS

Assessment of trial quality, data extraction and synthesis of data were performed using standard methods of the Cochrane Pain, Palliative and Supportive Care Group. We report mean differences (MD) with 95% confidence intervals (CI) using fixed-effect models as appropriate for continuous outcome measures. We planned to report risk ratio (RR) and risk difference (RD) for dichotomous outcomes. The Chi(2) test and I(2) statistic were used to assess between-study heterogeneity.

MAIN RESULTS

Sixty-five (65) studies were identified for possible inclusion in this review. Fourteen published RCTs with a total of 1551 participants met the inclusion criteria. Duration of cry was significantly reduced in infants who were administered a sweet-tasting solution [MD -13.47 (95% CI -16.80 to -10.15)], P < 0.00001 compared with water. However, there was considerable heterogeneity between the studies (I(2) = 94%) that we were unable to explain. Meta-analysis was not able to be undertaken for any of the other outcome measures, except for cry duration, because of differences in study design. However, most of the individual studies that measured pain found sucrose to significantly reduce pain compared with the control group. One study compared sucrose and Lidocaine-prilocaine cream and no significant difference was found between the two treatments for the outcomes pain and cry duration. Due to the differences between the studies, we were unable to identify the optimal concentration, volume or method of administration of sweet-tasting solutions in infants aged one to 12 months. Further large RCTs are needed.

AUTHORS' CONCLUSIONS

There is insufficient evidence to confidently judge the effectiveness of sweet-tasting solutions in reducing needle-related pain in infants (one month to 12 months of age). The treatments do, however, appear promising. Data from a series of individual trials are promising, as are the results from a subset meta-analysis of studies measuring duration of crying. Further well controlled RCTs are warranted in this population to determine the optimal concentration, volume, method of administration, and possible adverse effects.

The effectiveness of glucose in reducing needle-related procedural pain in infants

This systematic review examined the effectiveness of glucose in relieving needle-associated pain in infants. Meta-analysis was not undertaken, and there was variation in dose, administration method, concentration, and outcome measurement. Glucose was more effective than placebo in relieving infant pain as measured by behavioral outcomes, but there were mixed findings for physiological outcomes. Based on these findings, 25%-50% glucose appears effective for infant pain management.

The use of oral sucrose for procedural pain relief in infants up to six months of age: a randomized controlled trial

The aim of this study was to evaluate the effectiveness of oral sucrose in decreasing pain during minor procedures in infants of 1-6 months corrected age. A blinded randomized controlled trial with infants aged 4-26 weeks who underwent venipuncture, heel lance or intravenous cannulation were stratified by corrected age into > 4-12 weeks and > 12-26 weeks. They received 2 mL of either 25% sucrose or sterile water orally 2 minutes before the painful procedure. Nonnutritional sucking and parental comfort, provided in adherence to hospital guidelines, were recorded. Pain behavior was recorded using a validated 10 point scale at baseline, during and following the procedure. Data collectors were blinded to the intervention. A total of 21 and 20 infants received sucrose and water, respectively, in the > 4-12-week age group, and 21 and 22, respectively, in the > 12-26-week age group. No statistical differences were found in pain scores between treatment and control groups at any data collection points in either age group. Infants aged > 4-12 weeks who did nonnutritional sucking showed statistically significantly lower median pain scores at 1, 2, and 3 minutes after the procedure than those who did not suck. Infants aged > 4-26 weeks exhibited pain behavior scores that indicated moderate to large pain during painful procedures; however, there was insufficient evidence to show that 2 mL 25% sucrose had a statistically significant effect in decreasing pain. Infants should be offered nonnutritional sucking in compliance with the Baby Friendly Health Initiative during painful procedures.

Adding cocoa to sucrose: the effect on cold pain tolerance

The sweet taste of sucrose acts as an analgesic, whereas the taste of a bitter substance decreases pain tolerance. The present experiment explores the analgesic effect of a complex taste and asks how adding cocoa, a substance often associated with sweet foods but that has a bitter taste, to a sucrose solution affects cold pain tolerance. The 24 male participants were exposed to Cold Pressor Tests (CPTs) while holding 1 of 3 tastants in their mouths: water, sucrose, or sucrose with cocoa added. After each CPT, participants rated pain intensity and tastant qualities. Intraoral sucrose increased the amount of time that men were able to leave their hands in cold water, whereas the cocoa solution did not. Solutions did not differ in pleasantness or sweetness, but the cocoa solution was rated as more bitter. Bitterness ratings of cocoa exceeded the ratings of sucrose (corrected for water) by an average of 16.9% (P = 0.02), which, in turn, produced a 30% reduction in the duration of pain tolerance (P = 0.002). These results suggest that the addition of a bitter substance reduces cues to the nutritive value of sucrose that may drive its analgesic effect.

Evaluation of analgesic effect of skin-to-skin contact compared to oral glucose in preterm neonates

Nonpharmacological interventions are important alternatives for pain relief during minor procedures in preterm neonates. Skin-to-skin contact or kangaroo mother care is a human and efficient way of caring for low-weight preterm neonates. The aim of the present study was to assess the analgesic effect of kangaroo care compared to oral glucose on the response of healthy preterm neonates to a low-intensity acute painful stimulus. Ninety-five preterm neonates with a postmenstrual age of 28-36 weeks were randomly assigned to three groups in a single-blind manner. In group 1 (isolette, n=33), the neonate was in the prone position in the isolette during heel lancing and did not receive analgesia. In group 2 (kangaroo method, n=31), the neonate was held in skin-to-skin contact for 10 min before and during the heel-lancing procedure. In group 3 (glucose, n=31), the neonate was in the prone position in the isolette and received oral glucose (1 ml, 25%) 2 min before heel lancing. A smaller variation in heart rate (p=0.0001) and oxygen saturation (p=0.0012), a shorter duration of facial activity (brow bulge, eye squeeze and nasolabial furrowing) (p=0.0001), and a lower PIPP (Premature Infant Pain Profile) score (p=0.0001) were observed in group 2. In conclusion, skin-to-skin contact produced an analgesic effect in preterm newborns during heel lancing.

Non-pharmacological techniques for pain management in neonates

Significant progress in understanding the physiology, clinical correlates, and consequences of neonatal pain have resulted in greater attention to pain management during neonatal intensive care. A number of nonpharmacological therapies have been investigated, including nonnutritive sucking, with and without sucrose use, swaddling or facilitated tucking, kangaroo care, music therapy, and multi-sensorial stimulation. Although the efficacy of these approaches is clearly evident, they cannot provide analgesia for moderate or severe pain in the neonate. Further, some of these therapies cannot be effectively applied to all populations of critically ill neonates. Acupuncture, an ancient practice in Chinese medicine, has gained increasing popularity for symptom control among adults and older children. Acupuncture may provide an effective nonpharmacological approach for the treatment of pain in neonates, even moderate or severe pain, and should be considered for inclusion in a graduated multidisciplinary algorithm for neonatal pain management.

Diabetic neuropathies: unanswered questions

Diabetic neuropathies are the most common types of neuropathies worldwide. Although there has been significant progress in the understanding of the clinical aspects of these conditions, many questions remain unanswered or difficult to answer in terms of causation, risk factors and genetic susceptibility, effective treatments and restoration of nerve functions, and pain management. The major handicap in studying diabetic neuropathies is the lack of a suitable animal model that addresses acute and chronic events leasing to diabetic neuropathy. Unfortunately and despite numerous drug trials, other than strict glycemic control, which is often difficult to maintain, there are no other treatments to slow the progression or delay the development of diabetic neuropathy. This article attempts to highlight a few unanswered or controversial questions regarding diabetic neuropathies.

Pain reduction during pediatric immunizations: evidence-based review and recommendations

The pain associated with immunizations is a source of anxiety and distress for the children receiving the immunizations, their parents, and the providers who must administer them. Preparation of the child before the procedure seems to reduce anxiety and subsequent pain. The limited available data suggest that intramuscular administration of immunizations should occur in the vastus lateralis (anterolateral thigh) for children <18 months of age and in the deltoid (upper arm) for those >36 months of age. Controversy exists in site selection for 18- to 36-month-old children. A number of studies suggest that the ventrogluteal area is the most appropriate for all age groups. Longer needles are usually associated with less pain and less local reaction. During the injection, parental demeanor clearly affects the child's pain behaviors. Excessive parental reassurance, criticism, or apology seems to increase distress, whereas humor and distraction tend to decrease distress. Distraction techniques vary with the age, temperament, and interests of the child, but their efficacy is well supported in the literature. Sucrose solution instilled directly into the mouth or administered on a pacifier reduces evidence of distress reliably in children <6 months of age and should be used routinely. Although there is no perfect topical anesthetic available at this time, selective use for children who are particularly fearful or who have had negative experiences in the past is highly endorsed. Pressure at the site, applied with either a device or a finger, clearly reduces pain. Finally, in the era of multiple injections, it seems that parents prefer that multiple injections be given simultaneously, rather than sequentially, if there are enough personnel available. Immunizations are stressful for many children; until new approaches are developed, systematic use of available techniques can significantly reduce the burden of distress associated with these procedures.

Endogenous opiates and behavior: 2005

This paper is the 28th consecutive installment of the annual review of research concerning the endogenous opioid system, now spanning over a quarter-century of research. It summarizes papers published during 2005 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior (Section 2), and the roles of these opioid peptides and receptors in pain and analgesia (Section 3); stress and social status (Section 4); tolerance and dependence (Section 5); learning and memory (Section 6); eating and drinking (Section 7); alcohol and drugs of abuse (Section 8); sexual activity and hormones, pregnancy, development and endocrinology (Section 9); mental illness and mood (Section 10); seizures and neurologic disorders (Section 11); electrical-related activity, neurophysiology and transmitter release (Section 12); general activity and locomotion (Section 13); gastrointestinal, renal and hepatic functions (Section 14); cardiovascular responses (Section 15); respiration and thermoregulation (Section 16); immunological responses (Section 17).

Recent developments in the pharmacological management of pain in children

PURPOSE OF REVIEW

This review explores progress in developmental pharmacokinetics, pharmacogenomics and formulations of analgesic agents, and discusses potential implications for pain therapy.

RECENT FINDINGS

Characterization of the developmental pharmacokinetics of morphine, tramadol, paracetamol and nonsteroidal anti-inflammatory drugs has improved dosing in children. Oral sugar solutions have replaced the brandy/sugar pacifier and are effective for single painful events in neonates. Intravenous paracetamol offers increased dosing accuracy, and avoids absorption and bioavailability variability. New nitric-oxide-releasing versions of paracetamol and nonsteroidal anti-inflammatory drugs offer safer alternatives to their parent drugs with enhanced potency. Ketamine has come under a cloud for its possible effects on the neonatal developing brain, but it is being used increasingly in children to supplement opioids for pain after major surgery. Hopes that morphine analgesia may improve neurological outcome in premature babies have not materialized. Reports concerning chronic pain are generally case series and controlled trials are rare and nearly nonexistent in children.

SUMMARY

Unlicensed drug use in the very young will increase as familiarity increases. Pharmacogenomic studies have the potential to tailor drug therapy to the individual and decrease between-patient variability. Unfortunately, the pharmacodynamic knowledge in children of analgesic agents remains neglected and is usually extrapolated from adult data.