Oral opioids for chronic non-cancer pain: higher prevalence of hypogonadism in men than in women

Endorphins, Sexuality, and Reproduction

Beta-endorphin is secreted from the hypothalamus and pituitary in both mother and newborn. The placenta produces numerous pituitary hormones from the third month of pregnancy, one of which is βE. It has been suggested that βE has a role in the appetitive and precopulatory phase of sexual behavior in animals. An increase in endorphin levels during sexual activity in humans may contribute to attachment and bonding between partners, but contradictory reports in the literature question the association between sexuality and βE levels. The level of βE also increases during pregnancy, rises in early labor, peaks in late labor, and drops in the postpartum period. This fluctuation provides natural analgesia, raises the pain threshold, decreases the sensation of pain, or suppresses pain, and decreases fear levels during labor and birth. Beta-endorphin also protects the fetus from hypoxia during labor and birth and potential neural damage by aiding blood flow to the brain under hypoxic conditions. It has been suggested that a variety of pharmacologic and nonpharmacologic complementary therapies, when used in pregnancy, labor, and birth, activate the opioid receptors in the CNS and alter the sensation of pain during labor and birth, affect the mother-child attachment and affect sexual function. These studies report contradictory results that will be discussed in this chapter.

Effects of Brain Wave Vibration Training on the Pain and Fatigue Disturbance Symptom Cluster in Persons with Cancer: A Randomized Controlled Trial

Pain and fatigue disturbance constitute the most common symptom cluster in persons with cancer, causing physical and psychological problems associated with a decreased quality of life. This study investigated the effects of brain wave vibration (BWV) training on the pain and fatigue disturbance symptom cluster in persons with cancer. A total of 43 participants were voluntarily recruited and randomly assigned to the experimental group (BWV with therapeutic massage, n = 25) or the control group (conventional physical therapy with spontaneous physical activity, n = 18) (Randomized controlled trial registration number: KCT0005843). BWV with therapeutic massage was performed for a total of 24 sessions (70 min/day, 2 days/week for 12 weeks). The Breakthrough Pain Assessment Tool and Brief Fatigue Inventory were used to evaluate cancer-related pain (CRP) and cancer-related fatigue (CRF), respectively. Regarding CRP variables, the experimental group demonstrated significant improvements in the worst and typical episodes of breakthrough pain, pain distress, and interference with living a normal life compared to the control group. In CRF, there was no significant difference between the groups, although BWV training with therapeutic massage resulted in a significant difference between before and after the intervention. Therefore, our study suggests that BWV training with therapeutic massage is beneficial for improving CRP and CRF in cancer survivors.

Less Well-Known Consequences of the Long-Term Use of Opioid Analgesics: A Comprehensive Literature Review

BACKGROUND

The adverse effects of short-term opioid analgesics are well known and acknowledged; however, the spectrum of the sequelae of long-term use seems less clear. Some effects may remain undetected but still have the potential to cause harm and reduce patients' quality of life.

OBJECTIVE

To review the literature on the adverse effects of long-term opioid therapy.

METHODS

We performed a quasi-systematic search, analyzing articles published in the MEDLINE database between January 2000 and March 2021 that identified adverse effects of opioids used for chronic pain treatment.

RESULTS

Growing evidence indicates that there are multiple serious adverse effects of opioid treatment. Long-term opioid use may have significant effects on the endocrine, immune, cardiovascular, respiratory, gastrointestinal, and neural systems. Studies show that long-term opioid treatment increases the risk of fractures, infections, cardiovascular complications, sleep-disordered breathing, bowel dysfunction, overdose, and mortality. Opioids may potentially affect cancer development. Most consequences of the long-term use of opioids have been identified in studies of patients with non-malignant pain.

CONCLUSION

Studies indicate that long-term use of opioids increases the risk of drug-related events in a significant number of patients. Clinicians should be aware of these complications associated with prescribing opioids, discuss them with patients, prevent complications, if possible, and diagnose them early and manage adequately. More human studies are needed to assess the risk, including trials with individual opioids, because they have different adverse effect profiles.

Opioids and pituitary function: expert opinion

PURPOSE

Opioids are highly addictive potent analgesics and anti-allodynics whose use has dramatically increased in recent decades. The precipitous rise in opioid dependency and opioid use disorder is an important public health challenge given the risks for severely adverse health outcomes. The long-term opioid impact on hypothalamic-pituitary axes is particularly underappreciated among both endocrinologists and primary care physicians. We review the effects of opioids on hypothalamic-pituitary-target gland function and their implications for clinical practice.

METHODS

Experts in hypothalamic-pituitary disorders and opioid pharmacology reviewed recently published literature and considered strategies for diagnosing and managing these opioid-induced endocrine effects.

RESULTS

Opioid suppression of hypothalamic-pituitary axes can lead to hypogonadotropic hypogonadism, central adrenal insufficiency, and hyperprolactinemia. These important clinical manifestations are often under-estimated, poorly evaluated, and typically either untreated or not optimally managed. Data on biochemical testing for diagnosis and on the effect of hormone replacement in these patients is limited and prospective randomized controlled studies for guiding clinical practice are lacking.

CONCLUSIONS

Patients should be informed about risks for hypogonadism, adrenal insufficiency, and hyperprolactinemia, and encouraged to report associated symptoms. Based on currently available evidence, we recommend clinical and biochemical evaluation for potential central adrenal insufficiency, central hypogonadism, and/or hyperprolactinemia in patients chronically treated with opioids as well as the use of current expert guidelines for the diagnosis and treatment of these conditions.

Adrenal insufficiency

Adrenal insufficiency (AI) is a condition characterized by an absolute or relative deficiency of adrenal cortisol production. Primary AI (PAI) is rare and is caused by direct adrenal failure. Secondary AI (SAI) is more frequent and is caused by diseases affecting the pituitary, whereas in tertiary AI (TAI), the hypothalamus is affected. The most prevalent form is TAI owing to exogenous glucocorticoid use. Symptoms of AI are non-specific, often overlooked or misdiagnosed, and are related to the lack of cortisol, adrenal androgen precursors and aldosterone (especially in PAI). Diagnosis is based on measurement of the adrenal corticosteroid hormones, their regulatory peptide hormones and stimulation tests. The goal of therapy is to establish a hormone replacement regimen that closely mimics the physiological diurnal cortisol secretion pattern, tailored to the patient's daily needs. This Primer provides insights into the epidemiology, mechanisms and management of AI during pregnancy as well as challenges of long-term management. In addition, the importance of identifying life-threatening adrenal emergencies (acute AI and adrenal crisis) is highlighted and strategies for prevention, which include patient education, glucocorticoid emergency cards and injection kits, are described.

Opioids and Sickle Cell Disease: From Opium to the Opioid Epidemic

Sickle cell disease (SCD) is an inherited disorder of hemoglobin structure. The clinical effects of the sickle gene are pleiotropic in nature causing multiple phenotypic expressions associated with the various complications of the disease. The hallmark of the disease is pain that could be acute, chronic, nociceptive, or neuropathic that could occur singly or in various combinations. The acute vaso-occlusive painful crisis (VOC) is the most common cause of admissions to the Emergency Department and/or the hospital. Although progress has been made in understanding the pathophysiology of SCD as well as in developing preventive and curative therapies, effective pain management continues to lag behind and depend mostly on the use of opioids. This review describes the history of opioids from the ancient times of opium to the current use of the many controversial opioids. In addition, the major cause of death of patients with SCD is the complications of the disease itself and not the use of opioids. The use of opioids by patients with SCD has been stable over the years. Judicious use of opioids to treat sickle cell pain according to available guidelines could minimize the unnecessary suffering experienced by patients with SCD.

Clinical Presentation and Outcomes of Opioid-Induced Adrenal Insufficiency

OBJECTIVE

Opioid-induced adrenal insufficiency (OIAI) may develop in patients treated with chronic opioids due to suppression of the hypothalamic-pituitary-adrenal axis. Our objective was to describe the clinical manifestations, biochemical presentation, and clinical course of OIAI.

METHODS

A retrospective study of adults diagnosed with OIAI between 2006 and 2018 at an academic center. Opioid daily dose was converted into morphine milligram equivalents (MMEs).

RESULTS

Forty patients (women, n = 29 [73%]) taking chronic opioids at a daily median MME dose of 105 (60 to 200) mg and median duration of 60 (3 to 360) months were diagnosed with OIAI. Patients reported fatigue (n = 29, 73%), musculoskeletal pain (n = 21, 53%), and weight loss (n = 17, 53%) for a median of 12 (range, 1 to 132) months prior to diagnosis, and only 7.5% (n = 3) of patients were identified with OIAI through case detection. Biochemical diagnosis of OIAI was based on (1) low morning cortisol, baseline adrenocorticotropic hormone and/or dehydroepiandrosterone sulfate in 59% (n = 26) of patients or (2) abnormal cosyntropin stimulation test in 41% (n = 14) of patients. With glucocorticoid replacement, 16/23 (70%) patients with available follow-up experienced improvement in symptoms. Opioids were tapered or discontinued in 15 patients, of whom 10 were followed for adrenal function and of which 7 (70%) recovered from OIAI.

CONCLUSION

Minimum daily MME in patients diagnosed with OIAI was 60 mg. OIAI causes significant morbidity, and recognition requires a high level of clinical suspicion. Appropriate glucocorticoid treatment led to improvement of symptoms in 70%. Resolution of OIAI occurred following opioid cessation or reduction.

Prevalence of Opioid-Induced Adrenal Insufficiency in Patients Taking Chronic Opioids

CONTEXT

Chronic opioid use may lead to adrenal insufficiency because of central suppression of the hypothalamic-pituitary-adrenal axis. However, the prevalence of opioid-induced adrenal insufficiency (OIAI) is unclear.

OBJECTIVE

To determine the prevalence of OIAI and to identify predictors for the development of OIAI in patients taking opioids for chronic pain.

DESIGN

Cross-sectional study, 2016-2018.

SETTING

Referral center.

PATIENTS

Adult patients taking chronic opioids admitted to the Pain Rehabilitation Center.

MAIN OUTCOME MEASURE

Diagnosis of OIAI was considered if positive case detection (cortisol < 10 mcg/dL, ACTH < 15 pg/mL, and dehydroepiandrosterone sulfate < 25 mcg/dL), and confirmed after endocrine evaluation. Daily morphine milligram equivalent (MME) was calculated.

RESULTS

In 102 patients (median age, 53 years [range, 22-83], 67% women), median daily MME was 60 mg (3-840), and median opioid therapy duration was 60 months (3-360). Abnormal case detection testing was found in 11 (10.8%) patients, and diagnosis of OIAI was made in 9 (9%). Patients with OIAI were on a higher daily MME (median, 140 [20-392] mg vs 57 [3-840] mg, P = 0.1), and demonstrated a 4 times higher cumulative opioid exposure (median of 13,440 vs 3120 mg*months, P = 0.03). No patient taking <MME of 20 mg/day developed OIAI (sensitivity of 100% for MME > 20 mg); however, specificity of MME cutoff >20 mg was only 19%. After opioid discontinuation, 6/7 patients recovered adrenal function.

CONCLUSION

The prevalence of OIAI was 9%, with MME cumulative exposure being the only predictor for OIAI development. Patients on MME of 20 mg/day and above should be monitored for OIAI.

Opioids and the Hypothalamic-Pituitary-Gonadal (HPG) Axis

CONTEXT

Hypogonadism is a well-established consequence of opioid use. It has been reported in both men and women, although more widely studied in men.

EVIDENCE ACQUISITION

PubMed was searched for articles in English until December 2019 for opioids and hypogonadism. Bibliography of retrieved articles was searched for relevant articles.

EVIDENCE SYNTHESIS

The prevalence of opioid-induced hypogonadism (OIH) varies between studies but was reported to be 69% in a recent systematic review. There is large heterogeneity in the studies, with different factors shown to have stronger association with hypogonadism such as specific types of opioids, higher doses, and longer durations of use. The consequences of OIH include sexual dysfunction, depression, decreased quality of life, and low bone density. There is paucity of randomized controlled trials assessing the efficacy of testosterone replacement therapy (TRT) for OIH in men, and even less studies on treating OIH in women. TRT studies in men reported varying outcomes with some studies favoring and others showing no clear benefit of TRT on different measures.

CONCLUSIONS

Despite the high prevalence of OIH, it remains underrecognized and undertreated with multiple endocrine and metabolic consequences. A reasonable approach in patients using opioids includes informing them of this complication and its potential consequences, screening for signs and symptoms of hypogonadism then sex hormone levels if prolonged opioid use > 3 months, and treating patients diagnosed with hypogonadism, if and when clinically indicated, with sex hormones if chronic opioids are planned to be continued for ≥ 6 months.

Opioid-free spine surgery: a prospective study of 244 consecutive cases by a single surgeon

BACKGROUND CONTEXT

There have been no reported efforts to eliminate opioid use for elective spine surgery, despite its well-known drawbacks.

PURPOSE

We sought to test the hypothesis that opioid-free elective spine surgery, including lumbar fusions, can be performed with satisfactory pain control.

STUDY DESIGN/ SETTING

This study analyzes prospectively collected data from a single surgeon's patients who were enrolled into an institutional spine registry.

PATIENT SAMPLE

We enrolled every consecutive surgical patient of author RAB between January 1, 2018 and July 13, 2019.

OUTCOME MEASURES

The postsurgical opioid use, pain scores, emergency room visits, and readmissions were tracked.

METHODS

We developed a comprehensive program for opioid-free pain control after elective spine surgery. In the initial stage, opioids were given "PRN" only, while in the second stage, they were avoided altogether. Student's t tests were performed to compare pain scores, and regression analyses were performed to understand drivers of opioid use and pain.

RESULTS

Two hundred forty-four patients were studied, a third of whom underwent lumbar fusions. In the initial stage, 47% of patients took no opioids from recovery room departure until 1-month follow-up. During the second stage, 88% of patients took no opioids during that period. Pain scores were satisfactory, and there was no association between postoperative opioid use and either procedural invasiveness or pain scores. However, preoperative opioid use was associated with a nearly fivefold increased risk of postoperative use. Ninety-three percent of lumbar fusion patients who were opioid-free before surgery did not take a single opioid in the postoperative period.

CONCLUSION

Opioid-free elective spine surgery, including lumbar fusions, is feasible and effective. We suggest that opioid-free spine surgery be offered to patients who are opioid-naïve or who can be weaned off before the operation.

The Effect of Opiates on Bone Formation and Bone Healing

PURPOSE OF REVIEW

Opioids have been shown to be associated with an increased risk of fracture. The purpose of this paper is to review recent research into the effects of opioids on bone formation and bone healing in animal models and in human studies.

RECENT FINDINGS

Most opioids, such as morphine and fentanyl, negatively affected bone remodeling and bone healing in animal models. Conversely, remifentanil has been recently shown to promote in vitro osteoblast differentiation and to inhibit differentiation and maturation of osteoclasts, therefore reducing bone resorption. According to the possible negative role of opioids in bone healing, opioid antagonists have been shown to enhance bone mineralization, suggesting a possible therapeutic role in the future for osteoporosis. Other neuropeptides, such as the vasoactive intestinal peptide (VIP) and the neuropeptide Y (NPY), have been proved to promote osteogenesis. The increased risk of fractures among opioid users may be related to their central nervous system side effects or to the reduced bone density, partly due to their endocrine effects, and partly to their direct activity on bone cells. Clinical data strongly suggested a potential negative effect of opioids in bone healing. The risk of nonunion fracture is significantly increased in opioid users, and bone mass density was reduced in patients under long-term opioid treatment. The direct effects of opioids on bone remodeling appears evident from these reports. Not all opioids have the same potential for negatively impacting bone healing. Opioid antagonists may increase bone density and could represent a possible future treatment for low bone mass density pathologies. However, further trials are warranted to clarify the clinical relevance of these emerging findings from animal studies.

Opioid-induced endocrinopathies

The use of opioids is becoming a global epidemic, leading to a rise in the occurrence and recognition of the effects of opioid drugs on the endocrine system. Nonetheless, opioid-induced endocrinopathies still remain underdiagnosed, mainly because of symptom under-reporting by patients and poor clinician awareness. Hypogonadism is the most well recognised consequence of opioid use, but the inhibitory effects of opioid drugs on the hypothalamo-pituitary-adrenal axis and their negative effects on bone health also require attention. Hyperprolactinaemia might be detected in opioid users, but clinically relevant thyroid dysfunction has not been identified. The effects of opioids on other hormones have not been clearly defined. Assessment of gonadal and adrenal function (particularly if high index of clinical suspicion of hypogonadism or hypoadrenalism) and evaluation of bone health are advised in people that use opiods. Discontinuation or reduction of opioid dose and appropriate hormone replacement are the management approaches that should be considered for hypogonadism and hypoadrenalism. Further research is needed to facilitate the development of evidence-based guidelines on the diagnosis and optimal management of opioid-induced endocrinopathies.

Functional hypothalamic and drug-induced amenorrhea: an overview

BACKGROUND

Functional hypothalamic amenorrhea (FHA) is a form of chronic anovulation not due to identifiable organic causes and with adverse health consequences. The identification of women with this disorder or the precocious identification of women at risk is based on the knowledge of lifestyle risk factors or behaviors such as stress, weight loss, and excessive physical exercise that are known to negatively impact gonadal axis activity.

METHODS

In this overview, we described the most common forms of FHA, in particular stress-induced amenorrhea and overtraining-induced amenorrhea. In addition, although its mechanisms can differ from those involved in FHA, we reviewed the available literature on drug-induced amenorrhea, highlighting the clear connection between this condition and psychoactive drugs such as antipsychotics, antidepressants and anti-epilectics thus raising concern about the role that the abuse of substances such as opioids or alcohol can possibly have on the growing unexplained infertility of the female population.

Opioid-Induced Hypogonadism in the United States

Objective

To examine the incidence of screening, diagnosis, and treatment of hypogonadism among men treated with opioids in the United States.

Patients and Methods

Using one of the nation's largest commercial insurance databases, we identified 53,888 men aged 20 years or older who had 90 or more days of opioid prescriptions in a single 12-month period between January 1, 2010, and December 31, 2017, with no history of hypogonadism or testosterone therapy in the preceding 12 months. We matched this cohort to 53,888 men with 14 or fewer days of opioid prescriptions based on age, opioid initiation date, opioid indication, and comparable exclusion criteria. We assessed whether men, 14 or fewer days after initiation of opioid treatment, received a serum testosterone test, a diagnosis of hypogonadism, or a prescription for testosterone therapy. All men were followed up until they lost coverage from the commercial insurance plan, experienced one of the study outcomes, or the end of study (December 31, 2017).

Results

In the multivariable analyses-adjusting for age, year of opioid initiation, region, comorbid disease, glucocorticoid use, and health care utilization-the 53,888 prolonged opioid users, in comparison with 53,888 short-term users, had an increased incidence of serum testosterone screening (5991 [17.15%; 95% CI, 16.70%-17.61%] vs 3514 [11.55%; 95% CI, 11.11%-12.01%] at 5 years; hazard ratio [HR], 1.46; 95% CI, 1.38-1.55), hypogonadism diagnosis (3125 [9.44%; 95% CI, 9.09%-9.80%] vs 1421 [4.85%; 95% CI, 4.55%-5.16%; HR, 1.74; 95% CI, 1.60-1.90]), and receipt of testosterone therapy (1919 [5.76%; 95% CI, 5.49%-6.05%] vs 631 [2.21%; 95% CI, 2.04%-2.43%; HR, 2.41; 95% CI, 2.13-2.74]). Each of these findings persisted across multiple sensitivity analyses.

Conclusion

Prolonged opioid exposure was associated with increased rates of screening, diagnosis, and treatment for opioid-induced hypogonadism, but these rates were much lower than expected based on previous serum-based studies.

Prospective evaluation of hypogonadism in male metastatic renal cell carcinoma patients treated with targeted therapies

OBJECTIVES

To study the prevalence of hypogonadism in male patients with metastatic renal cell carcinoma (mRCC) starting with targeted therapies and the impact of the vascular endothelial growth factor receptor tyrosine kinase inhibitors (VEGFR-TKIs) sunitinib and pazopanib on the luteinizing hormone (LH)/testosterone (TT)-axis.

METHODS

Male mRCC patients starting with targeted therapies were prospectively included in this study. TT- and LH-levels were sampled at start as well as during systemic therapy. Endpoints of the study were gonadal status (TT- and LH-levels) at start of targeted therapy and TT- and LH-evolution during targeted therapy.

RESULTS

Sixty-three patients were included in this study. At start of targeted therapy, 30% of patients were eugonadal and 48% had secondary hypogonadism. Decreased TT- and increased LH-levels were associated with inflammatory state and poor prognosis. During sunitinib therapy, TT-levels decreased with 32% (p = 0.004) and LH-levels with 14% (p = 0.03). TT-levels were 13% lower (p = 0.007) and LH-levels 15% lower (p = 0.004) on day 28 compared to day 1. In four patients, a dramatic TT decrease was observed shortly after starting sunitinib. In patients treated with pazopanib, no impact on TT- or LH-levels was observed.

CONCLUSION

Hypogonadism is a frequent finding in male mRCC-patients at start of targeted therapies. In contrast to pazopanib, during sunitinib therapy, TT- and LH-levels tend to decrease, leading to an increased incidence of secondary hypogonadism.

Clinical Management of Congenital Hypogonadotropic Hypogonadism

The initiation and maintenance of reproductive capacity in humans is dependent on pulsatile secretion of the hypothalamic hormone GnRH. Congenital hypogonadotropic hypogonadism (CHH) is a rare disorder that results from the failure of the normal episodic GnRH secretion, leading to delayed puberty and infertility. CHH can be associated with an absent sense of smell, also termed Kallmann syndrome, or with other anomalies. CHH is characterized by rich genetic heterogeneity, with mutations in >30 genes identified to date acting either alone or in combination. CHH can be challenging to diagnose, particularly in early adolescence where the clinical picture mirrors that of constitutional delay of growth and puberty. Timely diagnosis and treatment will induce puberty, leading to improved sexual, bone, metabolic, and psychological health. In most cases, patients require lifelong treatment, yet a notable portion of male patients (∼10% to 20%) exhibit a spontaneous recovery of their reproductive function. Finally, fertility can be induced with pulsatile GnRH treatment or gonadotropin regimens in most patients. In summary, this review is a comprehensive synthesis of the current literature available regarding the diagnosis, patient management, and genetic foundations of CHH relative to normal reproductive development.

Testosterone deficiency in non-cancer opioid-treated patients

PURPOSE

The use of opioids in patients with chronic non-cancer pain is common and can be associated with opioid-induced androgen deficiency (OPIAD) in men. This review aims to evaluate the current literature regarding the prevalence, clinical consequence and management of OPIAD.

METHODS

A database search was performed in Medline, Embase and Cochrane using terms such as "analgesics", "opioids" and "testosterone". Relevant literature from January 1969 to March 2018 was evaluated.

RESULTS

The prevalence of patients with OPIAD ranges from 19 to 86%, depending on the criteria for diagnosis of hypogonadism. The opioid-induced suppression of gonadotropin-releasing and luteinizing hormones represents the main important pathogenetic mechanisms. OPIAD has significant negative clinical consequences on sexual function, mood, bone density and body composition. In addition, OPIAD can also impair pain control leading to hyperalgesia, which can contribute to sexual dysfunction and mood impairment.

CONCLUSIONS

OPIAD is a common adverse effect of opioid treatment and contributes to sexual dysfunction, impairs pain relief and reduces overall quality of life. The evaluation of serum testosterone levels should be considered in male chronic opioid users and the decision to initiate testosterone treatment should be based on the clinical profile of individuals, in consultation with the patient.

Endorphins, oxytocin, sexuality and romantic relationships: An understudied area

Endorphins are the body’s natural opioids that are created and released by the central nervous system, hypothalamus and pituitary gland. Endorphins have a reputation for pain reduction, enhancing excitement or satisfaction, boosting confidence, enabling control of emotions and generating feelings of euphoria, and are involved in the natural reward cycle. There is also evidence in the literature suggesting the role of endorphins in sexuality (including sexual function and sexual behaviours), as they may regulate the release of sex hormones, prolactin and growth hormone, which are involved in sexual function and love. Endogenous oxytocin is another intrinsic hormone whose role in inducing labour contractions, the delivery of the baby and stimulating lactation has been well studied. However, the potential impact of endorphins and oxytocin on sexuality and romantic relationships is not well understood. This article reviews the research on endorphins and endogenous oxytocin and how they relate to human sexuality and romantic relationships. Some animal studies report the effect of endorphin and oxytocin on sex hormones and mating behaviours, but these findings have not been supported by research into human behaviour, indicating many gaps in knowledge relating to the association between these hormones and human sexuality.

Opioids delay healing of spinal fusion: a rabbit posterolateral lumbar fusion model

BACKGROUND CONTEXT

Opioid use is prevalent in the management of pre- and postoperative pain in patients undergoing spinal fusion. There is evidence that opioids downregulate osteoblasts in vitro, and a previous study found that morphine delays the maturation and remodeling of callus in a rat femur fracture model. However, the effect of opioids on healing of spinal fusion has not been investigated before. Isolating the effect of opioid exposure in humans would be limited by the numerous confounding factors that affect fusion healing. Therefore, we have used a well-established rabbit model to study the process of spinal fusion healing that closely mimics humans.

PURPOSE

The objective of this work was to study the effect of systemic opioids on the process of healing of spinal fusion in a rabbit posterolateral spinal fusion model.

STUDY DESIGN/SETTING

This is a preclinical animal study.

MATERIALS AND METHODS

Twenty-four adult New Zealand white rabbits were studied in two groups after approval from the Institutional Animal Care and Use Committee (IACUC). The opioid group (n=12) received 4 weeks' preoperative and 6 weeks' postoperative transdermal fentanyl. Serum fentanyl levels were measured just before surgery and 4 weeks postoperatively to ensure adequate levels. The control group (n=12) received only perioperative pain control as necessary. All animals underwent a bilateral L5-L6 posterolateral spinal fusion using iliac crest autograft. Animals were euthanized at the 6-week postoperative time point, and assessment of fusion was done by manual palpation, plain radiographs, microcomputed tomography (microCT), and histology.

RESULTS

Twelve animals in the control group and 11 animals in the opioid group were available for analysis at the end of 6 weeks. The fusion scores on manual palpation, radiographs, and microCT were not statistically different. Three-dimensional microCT morphometry found that the fusion mass in the opioid group had a lower bone volume (p=.09), a lower trabecular number (p=.02), and a higher trabecular separation (p=.02) compared with the control group. Histologic analysis found areas of incorporation of autograft and unincorporated graft fragments in both groups. In the control group, there was remodeling of de novo woven bone to lamellar organization with incorporation of osteocytes, formation of mature marrow, and relative paucity of hypertrophied osteoblasts lining new bone. Sections from the opioid group showed formation of de novo woven bone, and hypertrophied osteoblasts were seen lining the new bone. There were no sections showing lamellar organization and development of mature marrow elements in the opioid group. Less dense trabeculae on microCT correlated with histologic findings of relatively immature fusion mass in the opioid group.

CONCLUSIONS

Systemic opioids led to an inferior quality fusion mass with delay in maturation and remodeling at 6 weeks in this rabbit spinal fusion model. These preliminary results lay the foundation for further research to investigate underlying cellular mechanisms, the temporal fusion process, and the dose-duration relationship of opioids responsible for our findings.

Assessment of gonadotropins and testosterone hormone levels in regular Mitragyna speciosa (Korth.) users

ETHNOPHARMACOLOGICAL RELEVANCE

Mitragyna speciosa (Korth.) also known as kratom, is a native medicinal plant of Southeast Asia with opioid-like effects. Kratom tea/juice have been traditionally used as a folk remedy and for controlling opiate withdrawal in Malaysia. Long-term opioid use is associated with depletion in testosterone levels.

AIM OF THE STUDY

Since kratom is reported to deform sperm morphology and reduce sperm motility, we aimed to clinically investigate the testosterone levels following long-term kratom tea/juice use in regular kratom users.

METHODS

A total of 19 regular kratom users were recruited for this cross-sectional study. A full-blood test was conducted including determination of testosterone level, follicle stimulating hormone (FSH) and luteinizing hormone (LH) profile, as well as hematological and biochemical parameters of participants.

RESULTS

We found long-term kratom tea/juice consumption with a daily mitragynine dose of 76.23-94.15 mg did not impair testosterone levels, or gonadotrophins, hematological and biochemical parameters in regular kratom users.

CONCLUSION

Regular kratom tea/juice consumption over prolonged periods (>2 years) was not associated with testosterone impairing effects in humans.

Understanding osteoporotic pain and its pharmacological treatment

Osteoporosis, a disorder that affects millions of people worldwide, is characterized by decreased bone mass and microstructural alterations giving rise to an increased risk of fractures. Osteoporotic fractures can cause acute and chronic pain that mainly affects elderly patients with multiple comorbidities and commonly on different drug regimens. The aim of this paper is to summarize the pathogenesis and systemic treatment of osteoporotic pain. This narrative review summarizes the main pathogenetic aspects of osteoporotic pain and the cornerstones of its treatment. Osteoporotic fractures induce both acute and chronic nociceptive and neuropathic pain. Central sensitization seems to play a pivotal role in developing and maintaining chronicity of post-fracture pain in osteoporosis. Antiosteoporosis drugs are able to partially control pain, but additional analgesics are always necessary for pain due to bone fractures. Nonsteroidal anti-inflammatory drugs (NSAIDs) and selective COX-2 inhibitors reduce acute pain but with a poor effect on the chronic neuropathic component of pain and with relevant side effects. Opioid drugs can control the whole spectrum of acute and chronic bone pain, but they differ with respect to their efficacy on neuropathic components, their tolerability and safety. Chronic pain after osteoporotic fractures requires a multifaceted approach, which includes a large spectrum of drugs (antiosteoporosis treatment, acetaminophen, NSAIDs, selective COX-2 inhibitors, weak and strong opioids) and non-pharmacological treatment. Based on a better understanding of the pathogenesis of osteoporotic and post-fracture pain, a guided stepwise approach to post-fracture osteoporotic pain will also better meet the needs of these patients.

Multiple signaling pathways convey central and peripheral signals to regulate pituitary function: Lessons from human and non-human primate models

The anterior pituitary gland is a key organ involved in the control of multiple physiological functions including growth, reproduction, metabolism and stress. These functions are controlled by five distinct hormone-producing pituitary cell types that produce growth hormone (somatotropes), prolactin (lactotropes), adrenocorticotropin (corticotropes), thyrotropin (thyrotropes) and follicle stimulating hormone/luteinizing hormone (gonadotropes). Classically, the synthesis and release of pituitary hormones was thought to be primarily regulated by central (neuroendocrine) signals. However, it is now becoming apparent that factors produced by pituitary hormone targets (endocrine and non-endocrine organs) can feedback directly to the pituitary to adjust pituitary hormone synthesis and release. Therefore, pituitary cells serve as sensors to integrate central and peripheral signals in order to fine-tune whole-body homeostasis, although it is clear that pituitary cell regulation is species-, age- and sex-dependent. The purpose of this review is to provide a comprehensive, general overview of our current knowledge of both central and peripheral regulators of pituitary cell function and associated intracellular mechanisms, focusing on human and non-human primates.

A comparison of bone quality and its determinants in young opioid-dependent women with healthy control group

BACKGROUND

Little is known about bone quality and its determinants in patients with opioid addiction. The goal of this study was to compare bone quality and its determinants in young opioid addicted women with a local group of young healthy women.

METHOD

Using cross-sectional design, 104 women (mean age 29.9 yrs, range: 20-40 yrs, SD=7.8) with previous opioid addiction and current methadone substitution (3-30mg, daily) for 1-16 weeks were compared to 117 healthy women (mean age 31.0 yrs, range: 20-40 yrs, SD=5.9). Bone quality was examined with quantitative ultrasound. Anthropometric characteristics (body weight, fat free mass (FFM), fat mass) were obtained by bioelectrical impedance analysis. Substance use and other risk factors for low bone quality were assessed by questionnaire-based interviews.

RESULTS

More than one-quarter (34%) of patients had osteopenia (n=31) or osteoporosis (n=4), compared to 16% of the healthy control group having osteopenia (n=18). Bivariate correlation analysis demonstrated that age, body weight, and FFM correlated with bone quality (p<0.05) in healthy women, which were not found in patients. Multivariate analyses showed that in healthy controls, the determinants of bone quality were age, body height, physical activity, and BMI, but in patients, the determinant of bone quality was duration of drug intake.

CONCLUSIONS

Long-term opioid dependence in young women may lead to low bone quality. Efforts to increase awareness of low bone quality in young opioid addicted women should be considered so that effective treatment may be employed to lower future fracture risk.

The relationship of salivary testosterone and male sexual dysfunction in opioid-associated androgen deficiency (OPIAD)

BACKGROUND

Opioids are an effective treatment for chronic non-malignant pain (CNP). Long-term use risks and side effects such as opioid-induced androgen deficiency (OPIAD) exist. This could be measured by saliva testosterone (Sal-T).

OBJECTIVES

To evaluate OPIAD in long-term opioid use in CNP patients.

METHODS

A cross-sectional study included CNP male outpatients under opioid treatment. Total-Testosterone (Total-T), Free-Testosterone (Free-T), Bio-Testosterone (Bio-T) and Sal-T were measured. Correlations were calculated by Spearman's rho (SPSS 20).

RESULTS

From 2012 to 2014, 134 from 249 (54%) consecutive male outpatients reported erectile dysfunction (ED), 37% of them related to opioids and 19% evidenced OPIAD. A total of 120 subjects (94 cases and 26 matched-controls) were included. A significantly lower luteinizing hormone, Total-T and Free-T were found, as well as, a significant correlation between Sal-T and Total-T (r = 0.234, p = 0.039), Bio-T (r = 0.241, p = 0.039), IIEF (r = 0.363, p = 0.003) and HAD-anxiety (r = -0.414, p = 0.012) in OPIAD patients. Sal-T levels were significantly lower in patients with severe-moderate ED versus mild ED (p = 0.045) and in patients with severe ED versus moderate-mild ED (p = 0.036).

CONCLUSIONS

These data demonstrate the high prevalence of ED in long-term use of opioids, part of this is associated to OPIAD, which can be tested by Sal-T as a non-invasive approach.

Adrenal insufficiency in patients on long-term opioid analgesia

OBJECTIVE

Opioid analgesia has been implicated as a cause of secondary adrenal insufficiency, but little is known of the prevalence of this potentially serious adverse effect in patients with chronic pain.

DESIGN

Cross-sectional study of chronic pain patients on long-term opioid analgesia.

PATIENTS

Patients attending tertiary chronic pain clinics at the Western General Hospital, Edinburgh, treated with long-term opioid analgesia (n = 48) with no recent exposure to exogenous glucocorticoids.

RESULTS

Four patients (8·3%) had basal morning plasma cortisol concentrations below 100 nmol/l, of whom three failed to achieve a satisfactory cortisol response to exogenous ACTH_1-24 stimulation (peak cortisol >430 nmol/l). Basal cortisol was positively associated with age (R = 0·398, P = 0·005) and negatively associated with BMI (R = -0·435, P = 0·002).

CONCLUSIONS

Suppression of the hypothalamic-pituitary-adrenal axis is present in a clinically significant proportion of chronic pain patients treated with opioid analgesia. Studies of larger populations should be conducted to better define the prevalence and potential clinical consequences of adrenal insufficiency in this context.

Implications of analgesics use in osteoporotic-related pain treatment: focus on opioids

Bone loss is asymptomatic and will progress without pain and other symptoms until the occurrence of a fracture. The occurrence of a breaking bone induce acute pain determined and supported by a mechanical, inflammatory and neuropathic component. Very often the acute component evolves in a chronic musculoskeletal component. Overall objectives of the analgesic therapy can be summarized in pain relief, improving sleep, improve mobility, reduce anxiety, emotional component and depression. Osteoporosis is predominantly a condition of the elderly, more likely to have coexisting cardiovascular disease and age-related decline in renal function, receiving treatment for one or more comorbid conditions, taking multiple medications. Analgesic treatment with NSAIDs has negative effects on skeletal health and healing of the injured skeleton and increase risk of adverse events especially in older patients. Despite all opioids therapy represents a mainstay in the treatment of patients with moderate to severe pain, it can induce an endocrinopathy, which may affect bone metabolism. The negative effects of opioids on hormonal axis are not the same for all molecule and the choice of drug can be crucial in the treatment of patients with chronic pain.

Diagnosis and management of testosterone deficiency

Testosterone supplementation therapy (TST) use has dramatically increased over the past decade, due to the availability of newer agents, aggressive marketing, and an increasing incidence of testosterone deficiency (TD). Despite the increase in TST, a degree of ambiguity remains as to the exact diagnostic criteria of TD, and administration and monitoring of TST. One explanation for this phenomenon is the complex role testosterone plays in multiple physiologic pathways. Numerous medical co-morbidities and medications can alter testosterone levels resulting in a wide range of nonspecific clinical signs and symptoms of TD. The diagnosis is also challenging due to the lack of a definitive serum total testosterone level that reliably correlates with symptoms. This observation is particularly true in the aging male and is exacerbated by inconsistencies between different laboratory assays. Several prominent medical societies have developed guideline statements to clarify the diagnosis, but they differ from each other and with expert opinion in several ways. Aside from diagnostic dilemmas, there are numerous subtle advantages and disadvantages of the various testosterone agents to appreciate. The available TST agents have changed significantly over the past decade similar to the trends in the diagnosis of TD. Therefore, as the usage of TST increases, clinicians will be challenged to maintain an up-to-date understanding of TD and TST. The purpose of this review is to provide a clear description of the current strategies for diagnosis and management of TD.

Controversies in testosterone supplementation therapy

Testosterone has now become one of the most widely used medications throughout the world. The rapid growth of the testosterone market in the past 10 years is due to many factors. We currently have a worldwide aging population. In the US, the number of men 65 years old or older is increasing 2–3 times faster than the number of men younger than 65 years. In addition, poor general health and certain medical conditions such as diabetes/metabolic syndrome (MetS), cardiovascular disease (CVD), and osteoporosis have been associated with low serum testosterone levels.123 There are now fewer concerns regarding the development of prostate cancer (PCa) after testosterone therapy, making it a more attractive treatment option. Finally, the introduction of different forms of testosterone supplementation therapy (TST) with increased promotion, marketing, and direct-to-consumer advertising is also driving market growth. As the demand for TST continues to grow, it is becoming more important for clinicians to understand how to diagnose and treat patients with low testosterone.

The unsolved case of "bone-impairing analgesics": the endocrine effects of opioids on bone metabolism

The current literature describes the possible risks for bone fracture in chronic analgesics users. There are three main hypotheses that could explain the increased risk of fracture associated with central analgesics, such as opioids: 1) the increased risk of falls caused by central nervous system effects, including sedation and dizziness; 2) reduced bone mass density caused by the direct opioid effect on osteoblasts; and 3) chronic opioid-induced hypogonadism. The impact of opioids varies by sex and among the type of opioid used (less, for example, for tapentadol and buprenorphine). Opioid-associated androgen deficiency is correlated with an increased risk of osteoporosis; thus, despite that standards have not been established for monitoring and treating opioid-induced hypogonadism or hypoadrenalism, all patients chronically taking opioids (particularly at doses ≥100 mg morphine daily) should be monitored for the early detection of hormonal impairment and low bone mass density.

Neuroendocrine causes of amenorrhea--an update

CONTEXT

Secondary amenorrhea--the absence of menses for three consecutive cycles--affects approximately 3-4% of reproductive age women, and infertility--the failure to conceive after 12 months of regular intercourse--affects approximately 6-10%. Neuroendocrine causes of amenorrhea and infertility, including functional hypothalamic amenorrhea and hyperprolactinemia, constitute a majority of these cases.

OBJECTIVE

In this review, we discuss the physiologic, pathologic, and iatrogenic causes of amenorrhea and infertility arising from perturbations in the hypothalamic-pituitary-adrenal axis, including potential genetic causes. We focus extensively on the hormonal mechanisms involved in disrupting the hypothalamic-pituitary-ovarian axis.

CONCLUSIONS

A thorough understanding of the neuroendocrine causes of amenorrhea and infertility is critical for properly assessing patients presenting with these complaints. Prompt evaluation and treatment are essential to prevent loss of bone mass due to hypoestrogenemia and/or to achieve the time-sensitive treatment goal of conception.

Opioids for low back pain

Back pain affects most adults, causes disability for some, and is a common reason for seeking healthcare. In the United States, opioid prescription for low back pain has increased, and opioids are now the most commonly prescribed drug class. More than half of regular opioid users report back pain. Rates of opioid prescribing in the US and Canada are two to three times higher than in most European countries. The analgesic efficacy of opioids for acute back pain is inferred from evidence in other acute pain conditions. Opioids do not seem to expedite return to work in injured workers or improve functional outcomes of acute back pain in primary care. For chronic back pain, systematic reviews find scant evidence of efficacy. Randomized controlled trials have high dropout rates, brief duration (four months or less), and highly selected patients. Opioids seem to have short term analgesic efficacy for chronic back pain, but benefits for function are less clear. The magnitude of pain relief across chronic non-cancer pain conditions is about 30%. Given the brevity of randomized controlled trials, the long term effectiveness and safety of opioids are unknown. Loss of long term efficacy could result from drug tolerance and emergence of hyperalgesia. Complications of opioid use include addiction and overdose related mortality, which have risen in parallel with prescription rates. Common short term side effects are constipation, nausea, sedation, and increased risk of falls and fractures. Longer term side effects may include depression and sexual dysfunction. Screening for high risk patients, treatment agreements, and urine testing have not reduced overall rates of opioid prescribing, misuse, or overdose. Newer strategies for reducing risks include more selective prescription of opioids and lower doses; use of prescription monitoring programs; avoidance of co-prescription with sedative hypnotics; and reformulations that make drugs more difficult to snort, smoke, or inject.

Elucidating risk factors for androgen deficiency associated with daily opioid use

BACKGROUND

Opioids can suppress testosterone in men, which can lead to extensive morbidity. Identifying risk factors for androgen deficiency in men using daily opioids could improve monitoring and safety.

METHODS

In a retrospective cohort study, we used Kaiser Permanente Northern California databases to identify men on stable doses of opioids. These subjects had no diagnoses of cancer or endocrine disorders except treated primary hypothyroidism. Subjects were divided into those using long-acting opioids and short-acting opioids. Total testosterone was measured in blood drawn in the morning while the subjects were on their regular dose of opioid. The association between opioid duration of action and androgen deficiency, controlling for dose, body mass index, age, diabetes, hyperlipidemia, and hypertension, was assessed using logistic regression.

RESULTS

The study included 1585 men. Men on long-acting opioids were more likely to be androgen deficient than men on short-acting opioids (57% vs 35%, P < 0.001; odds ratio [OR] 3.39; 95% confidence interval [CI], 2.39-4.77). As dose increased, the odds of androgen deficiency increased; however, dose was more strongly associated with androgen deficiency in men on short-acting opioids (OR 1.16; 95% CI, 1.09-1.23, for each 10-mg increase in dose) than in men on long-acting opioids (OR 1.01; 95% CI, 1.01-1.02).

CONCLUSION

Use of long-acting opioids is a key risk factor in the development of androgen deficiency. Dose was significantly associated with androgen deficiency, but more so for men on short-acting than on long-acting opioids.