Intravenous morphine and nalbuphine increase histamine and catecholamine release without accompanying hemodynamic changes

[Bronchial diseases and heroin use. A systematic review]

INTRODUCTION

Heroin use can cause respiratory complications including asthma, chronic obstructive pulmonary disease (COPD) and bronchiectasis (BD).

OBJECTIVES

A general review of the literature presenting the data on the relationships between heroin consumption and bronchial complications, while underlining the difficulties of diagnosis and management.

DOCUMENTARY SOURCES

Medline, 1980-2022, keywords "asthma" or "bronchospasm" or "COPD" or "bronchiectasis" and "heroin" or "opiate" or "opiates", with limits pertaining to "Title/Abstract". Concerning asthma, 26 studies were included, as were 16 for COPD and 5 for BD.

RESULTS

Asthma and COPD are more prevalent among heroin addicts, who are less compliant than other patients with their treatment. The authors found a positive association between frequency of asthma exacerbations, admission to intensive care and heroin inhalation. Late diagnosis of COPD worsens the course of the disease; emphysema and BD are poor prognostic factors.

CONCLUSION

Bronchial diseases in heroin users can be identified by means of respiratory function exploration and chest CT scans. These tests should be performed frequently in view of optimizing their care, which includes their weaning themselves from addictive substances.

[Asthma and heroin use]

INTRODUCTION

Heroin use can be responsible for many respiratory complications including asthma.

OBJECTIVES

Systematic literature review of data on asthma in heroin users.

DOCUMENTARY SOURCES

Medline®, on the period 1980-2017 with the following keywords: keywords: "asthma" or "bronchospasm" and "heroin" or "opiate" or "opiates", limits "title/abstract"; the selected languages were English or French. Among 97 articles, 67 abstracts have given use to a dual reading to select 23 studies.

RESULTS

The seven case reports included 21 patients (mean age: 28 years [19-46 years]; sex-ratio: 2.5 [males: 71.5%]). Heroin was inhaled (71.4%), sniffed (19%) or injected by intravenous route (9.5%). Associated addictive substances were tobacco (81%), cannabis (38%), alcohol (4.7%) and cocaine (4.7%). Outcome was fatal in 3 subjects (14.3%). Other studies included one cross-sectional study, 3 case-control studies and 12 longitudinal studies (11 retrospective studies and one prospective study). The proportion of heroin users was higher in asthmatic subjects and the prevalence of asthma and bronchial hyperreactivity was higher in heroin users. Heroin use can be responsible for asthma onset, with a temporal relationship between the onset of heroin use and asthma onset in 28 to 31% of subjects. A positive association between inhaled heroin use and acute asthma exacerbation was observed. Asthma treatment observance was lower in heroin users. In case of asthma exacerbation, heroin users were more likely to seek care in the emergency department, to be admitted in intensive care units and to require intubation and invasive ventilation. Asthma deaths related to heroin use mainly occurred following an intravenous injection (especially in the case of overdose), but also following heroin use by nasal (sniff) or pulmonary route.

CONCLUSION

Heroin use may be responsible for asthma onset, acute asthma exacerbations (which may require intubation and invasive ventilation) or deaths related to asthma. Heroin use must be sought in case of asthma exacerbation in young persons and practitioners must help heroin users to stop their consumption.

Near Fatal Asthma in an Inner City Population

Near-fatal asthma (NFA) is highly prevalent in inner city population. Patients who present with NFA require timely intervention, which necessitates knowledge of appropriate associated risk factors. The purpose of the study was to look and identify the salient features of an asthma exacerbation that are more likely to be associated with NFA in inner city population. We conducted a retrospective analysis of patients who were discharged from the hospital with a diagnosis of acute asthma exacerbation. Two hundred eighteen patients were included in the study. Patients who required intubation during the course of their hospitalization were defined as NFA and the rest were defined as non-near-fatal asthma (NNFA). Multiple patient parameters were compared between the 2 groups; 60 patients met the definition of NFA. There was no difference between NFA and NNFA groups with respect to sex, race, and history of smoking and asthma treatment modalities before presentation. NFA was seen more commonly in heroin (40% vs. 25.9%; P < 0.05) and cocaine users (28.3% vs. 16.5%; P < 0.05). A history of exacerbation requiring intensive care unit (ICU) care was more common among the NFA patients (55% vs. 40.5%; P = 0.05). A history of intubation for an exacerbation was more commonly seen in patients presenting with NFA (51.7% vs. 35.4%; P < 0.05). The NNFA group was more likely to have a primary care physician and to be discharged home (65.6% vs. 51.7%, P < 0.05; and 71.7 vs. 79.1%, P < 0.05). In a multi-logistic regression model, including age, sex, race, heroin and cocaine use, history of intubation and ICU admission, medications, use of noninvasive ventilation, primary care physician, and pH <7.35, PCO2 >45 mm Hg, and FiO2 >40% on initial blood gas, NFA was predicted only by PaCO2 >45 [odds ratio (OR = 6.7; P < 0.001)] and FiO2 >40% (OR = 3.5; P = 0.002). Use of noninvasive ventilation was a negative predictor of NFA (OR = 0.2; P < 0.001). Asthmatic patients who carry a history of intubation with mechanical ventilation for an asthma exacerbation, admissions to the ICU, or those who indulge in recreational drugs like cocaine or heroin should be closely monitored for clinical deterioration.

Profile of Acute Asthma Exacerbation in Drug Users

The characteristics of patients who use heroin, cocaine, or both and present with acute asthma exacerbations have not been well studied. In this retrospective study, we aimed to study the demographic characteristics of this patient population, the characteristics of their asthma attack, and the risk factors for the need for invasive mechanical ventilation in this patient population. We reviewed the charts of patients discharged from an inner-city hospital with a diagnosis of acute asthma exacerbation. Individuals who used either heroin or cocaine or both within 24 hours of presenting to the emergency department were identified as a cohort of drug users. The rest were classified as non-drug users. Both groups were compared, and a univariate analysis was performed. To assess the predictive value of drug use for the need for intubation in the presence of confounding factors, logistic regression analysis was performed to identify whether using cocaine or heroin or both was an individual predictor for the need for invasive ventilation. Data from 218 patients were analyzed. Drug users (n = 85) were younger (mean age in years 43.9 vs. 50.5, P < 0.01), predominantly male (63.5% vs. 33.8%, P < 0.01), and more likely to be cigarette smokers (90.6% vs. 57.6%, P < 0.01). A medical history of intubation and admissions to the intensive care unit (ICU) was more common among drug users (56.5% vs. 29.3%, P < 0.01 and 54.1% vs. 38.3%, P < 0.03, respectively). Drug use was associated with increased need for invasive mechanical ventilation (35% vs. 23.3%, P = 0.05). Non-drug users were more likely to be using inhaled corticosteroids (48.9% vs. 32.9%, P = 0.03) and had longitudinal care established with a primary care provider (50.6% vs. 68.9%, P < 0.01). After adjusting for a history of mechanical ventilation, history of ICU admission, use of systemic corticosteroids, smoking, and acute physiological assessment and chronic health evaluation 2 score, drug use remained predictive for the need for mechanical ventilation (P = 0.026). Acute asthma exacerbations triggered by cocaine and heroin should be treated aggressively because they represent a cohort with poor follow-up and undertreated asthma as outpatients and are associated with increased need for invasive mechanical ventilation and ICU admission during acute exacerbation.

Clinical Toxicology and Its Relevance to Asthma and Atopy

Although both the prevalence of asthma and the prescription drug use, notably the opiate analgesic class, epidemics are increasing, there is a complex interplay between both disorders, with both protective and exacerbating factors involved in the effect of opiates on asthma pathogenesis and clinical severity. This review examines the airway effects, both immunologic and neurologic, of opiates, which may interact and result in protection or exacerbation of asthma.

Medical diagnoses associated with substance dependence among inpatients at a large urban hospital

Background

There are limited data on reasons for hospital admission among patients dependent on substances other than alcohol. We compared primary discharge diagnoses for heroin- or cocaine-dependent patients to non-dependent patients.

Material and Methods

We evaluated a cohort of patients admitted to a general medicine service at a public teaching hospital during July 2005-June 2008. Through bedside interviews, we identified patients who had substance-use disorders. We categorized patients by substance used, route of administration, and dependent or non-dependent use. We grouped diagnostic codes (i.e., ICD-9) using Healthcare Utilization Project categories. We excluded HIV-infected patients.

Results

Of 11,397 patients, 341 (3.0%) were dependent on inhalational heroin, 260 (2.3%) on non-injection cocaine, and 106 (0.9%) on injection heroin. Compared to non-dependent patients, inhalational heroin-dependent patients were over three-fold more likely to have been admitted for respiratory diseases (28% vs. 8%, p<0.01); this association was strongest for asthma exacerbation (OR=7.0; 95% CI, 4.7 to 70.4, p<0.01). Of the 225 admissions for an asthma exacerbation, 44 (19.6%) had co-occurrent heroin-dependence. The most frequent diagnostic category among cocaine-dependent patients was circulatory, which was similar to non-dependent patients (22% vs. 21%, p=0.92).

Discussion

There is a strong association between heroin dependence and hospital admission for an asthma exacerbation. Provision of specialized substance-use treatment for inhalational heroin users will be necessary to reduce the frequency of exacerbations and repeat hospital admissions.

[Nalbuphine in pediatric anesthesia]

Efficient and safe pediatric perioperative pain therapy in the context of a multimodal pain therapy concept requires a slight to moderate opioid analgesic. Nalbuphine is a nearly ideal opioid for this purpose due to its unique pharmacological properties as a μ-receptor antagonist/κ-receptor agonist and a high safety profile. Nalbuphine is used clinically primarily in postoperative pain therapy administered as a bolus, continuous infusion and patient-controlled analgesia. Furthermore, it is administered in different regimens for pediatric diagnostic and interventional sedation.

[Urological surgery with analogosedation and local anesthesia. What makes sense?]

OBJECTIVE

Analogosedation and local anesthesia, including regional nerve blocks are used for endoscopic diagnostic or radiological and ultrasound-guided procedures in which the patient should not move or has to be free of pain. We retrospectively analyzed patient satisfaction, complications and the risk of urological interventions with analgosedation and/or local anesthesia between 2008 and 2012.

MATERIAL AND METHODS

In total 21,690 urological patients underwent surgical treatment at the Department of Urology of the University Hospital of Essen between 2008 and 2012 and 3,327 of these cases were performed by urologists with the patient under analogosedation (n=1484) and local anesthesia (n=1843). In total 13 surgical and endoscopic procedures were separately analyzed and evaluated for safety and practicability.

RESULTS

In five cases (0.15%) the procedures with analgosedation or local anesthesia were interrupted because of agitation (n=3) and in one case the transurethal resection was stopped due to a large bladder tumor. One patient suffered anaphylactic shock after preoperative intravenous application of cefuroxim 1.5 g. After cardiopulmonary resuscitation and a short stay on the intensive care unit the patient was discharged after 2 days.Conclusions. Local anesthesia and analgosedation should be performed by urologists for minor surgery, endoscopic procedures and radiological or ultrasound-guided treatment. For safety reasons there should always be a second medical doctor present for assistance. Analgesia with deep sedation or loss of defensive reflexes should be administered by anesthesiologists.

Fentanyl enhances the excitability of rapidly adapting receptors to cause cough via the enhancement of histamine release in the airways

Background

Although the mechanism of fentanyl-induced cough is unclear, several lines of evidence suggest that allergic mediators, such as histamine, may play a role in the production of fentanyl-induced coughs. The aim of this study was to explore the effects of fentanyl on cough sensitivity to inhaled citric acid and on histamine release in BALF in mice.

Methods

The cough reflex was induced by the inhalation of citric acid. Male ICR mice were exposed to a nebulized solution of citric acid at a concentration of 0.1 M under conscious and identical conditions using a body plethysmograph. The number of coughs produced per 3-min period of exposure to citric acid was counted. Histamine content in BALF was analyzed by HPLC post-column derivatization and fluorescence detection.

Results

Intravenous administration of fentanyl increased the number of citric acid-induced coughs. The fentanyl-induced enhancement of the number of citric acid-induced coughs was abolished in mice that had been pretreated with moguisteine, a rapidly adapting receptor (RAR) antagonist or fexofenadine, a histamine H1 receptor antagonist. Fentanyl significantly increased the concentration of histamine in BALF.

Conclusion

The results of this study suggest that fentanyl enhances the excitability of RARs to cause cough, and enhancement of histamine release in the airways may some how be related to this change.

Histamine-releasing and allergenic properties of opioid analgesic drugs: resolving the two

Opioid analgesics are amongst the most commonly administered drugs in hospitals. Whether natural or synthetic, they show some common structural features, morphine-like pharmacological action and binding specificity for complementary opioid receptors. Tramadol differs from the other opioid analgesics in possessing monoaminergic activity in addition to its affinity for the µ opioid receptor. Many opioids are potent histamine releasers producing a variety of haemodynamic changes and anaphylactoid reactions, but the relationship of the appearance of these effects to the histamine plasma concentration is complex and there is no direct and invariable relationship between the two. Studies of the histamine-releasing effects, chiefly centred on morphine, reveal variable findings and conclusions often due to a range of factors including differences in technical measurements, dose, mode of administration, site of injection, the anatomical distribution of histamine receptors and heterogeneity of patient responses. Morphine itself has multiple direct effects on the vasculature and other haemodynamically-active mediators released along with histamine contribute to the variable responses to opioid drug administration. Despite their heavy use and occasional apparent anaphylactic-like side-effects, immunoglobulin E antibody-mediated immediate hypersensitivity reactions to the drugs are not often encountered. Uncertainties associated with skin testing with these known histamine-releasers, and the general unavailability of opioid drug-specific immunoglobulin E antibody tests contribute to the frequent failure to adequately investigate and establish underlying mechanisms of reactions by distinguishing anaphylactoid from true anaphylactic reactions. Clinical implications for diagnosis of reactions and some speculations on the rarity of true Type 1 allergies to these drugs are presented.

Successful implementation of a pediatric sedation protocol for mechanically ventilated patients

OBJECTIVE

To evaluate the effect of a nursing-driven sedation protocol for mechanically ventilated pediatric patients on duration of use of analgesic and sedative medications. We hypothesized that a protocol would decrease length of sedation use and decrease days of mechanical ventilation and length of stay.

DESIGN

Retrospective cohort study with historical controls.

SETTING

Thirty-one-bed tertiary care, medical-surgical-cardiac pediatric intensive care unit in a metropolitan university-affiliated children's hospital.

PATIENTS

Children requiring mechanical ventilation longer than 48 hrs not meeting exclusion criteria.

INTERVENTIONS

Before protocol implementation, sedation was managed per individual physician orders. During the intervention period, analgesia and sedation were managed by nurses following an algorithm-based sedation protocol based on a comfort score.

MEASUREMENTS AND MAIN RESULTS

The observation group included consecutive patients admitted during the 12-month period before protocol education and implementation (n = 153). The intervention group included patients admitted during the 12 months following protocol implementation (n = 166). The median duration of total sedation days (intravenous plus enteral) was 7 days for the observation period and 5 days for the intervention period (p = .026). Specifically, the median duration of morphine infusion was 6 days for the observation period and 5 days for the intervention period (p = .015), whereas the median duration of lorazepam infusion was 2 days for the observation period and 0 days for the intervention period. After adjusting for severity of illness with the pediatric risk of mortality III (PRISM III) score, the Cox proportional hazards regression analysis demonstrated that at any point in time, patients in the intervention group were 23% more likely to be off all sedation (heart rate 0.77, p = .020). Additionally, the intervention group tended to be associated with fewer days of mechanical ventilation (heart rate 0.81, p = .060) and decreased pediatric intensive care unit length of stay (heart rate 0.81, p = .058), although these associations did not quite reach statistical significance.

CONCLUSION

A pediatric sedation protocol can significantly decrease days of benzodiazepine and opiate administration, which may improve pediatric intensive care unit resource utilization.

Morphine is an arteriolar vasodilator in man

AIM

The mechanisms of action of morphine on the arterial system are not well understood. The aim was to report forearm vascular responses, and their mediation, to intra-arterial morphine in healthy subjects.

METHODS

Three separate protocols were performed: (i) dose ranging; (ii) acute tolerance; (iii) randomized crossover mechanistic study on forearm blood flow (FBF) responses to intrabrachial infusion of morphine using venous occlusion plethysmography. Morphine was infused either alone (study 1 and 2), or with an antagonist: naloxone, combined histamine-1 and histamine-2 receptor blockade or during a nitric oxide clamp.

RESULTS

Morphine caused an increase in FBF at doses of 30 microg min(-1)[3.25 (0.26) ml min(-1) 100 ml(-1)][mean (SEM)] doubling at 100 microg min(-1) to 5.23 (0.53) ml min(-1) 100 ml(-1). Acute tolerance was not seen to 50 microg min(-1) morphine, with increased FBF [3.96 (0.35) ml min(-1) 100 ml(-1)] (P = 0.003), throughout the 30-min infusion period. Vasodilatation was abolished by pretreatment with antihistamines (P = 0.008) and the nitric oxide clamp (P < 0.001), but not affected by naloxone. The maximum FBF with pretreatment with combined H1/H2 blockade was 3.06 (0.48) and 2.90 (0.17) ml min(-1) 100 ml(-1) after 30 min, whereas with morphine alone it reached 4.3 (0.89) ml min(-1) 100 ml(-1).

CONCLUSIONS

Intra-arterial infusion of morphine into the forearm circulation causes vasodilatation through local histamine-modulated nitric oxide release. Opioid receptor mechanisms need further exploration.

Pain management principles in the critically ill

This article addresses conventional pharmacologic and nonpharmacologic treatment of pain in patients in ICUs. For the critically ill patient, opioids have been the mainstay of pain control. The optimal choice of opioid and dosing regimen for a specific patient varies depending on factors such as the pharmacokinetics and physicochemical characteristics of an opioid and the body's handling of the opioid, concomitant sedative regimen, potential or actual adverse drug events, and development of tolerance. The clinician must appreciate that favorable pharmacokinetic properties such as a short-elimination half-life do not necessarily translate into clinical advantages in the ICU setting. A variety of medications have been proposed as alternatives or adjuncts to the opioids for pain control that have unique considerations when contemplated for use in the critically ill patient. Most have been relatively unstudied in the ICU setting, and many have limitations with respect to availability of the GI route of administration in patients with questionable GI absorptive function. Nonpharmacologic, complementary therapies are low cost, easy to provide, and safe, and many clinicians can implement them with little difficulty or resources. However, the evidence base for their effectiveness is limited. At present, insufficient research evidence is available to support a broad implementation of nonpharmacologic therapies in ICUs.

Adverse drug reactions in patients with phaeochromocytoma: incidence, prevention and management

The dangers of phaeochromocytomas are mainly due to the capability of these neuroendocrine tumours to secrete large quantities of vasoactive catecholamines, thereby increasing blood pressure and causing other related adverse events or complications. Phaeochromocytomas are often missed, sometimes only becoming apparent during therapeutic interventions that provoke release or interfere with the disposition of catecholamines produced by the tumours. Because phaeochromocytomas are rare, evidence contraindicating use of specific drugs is largely anecdotal or based on case reports. The heterogeneous nature of the tumours also makes adverse reactions highly variable among patients. Some drugs, such as dopamine D(2) receptor antagonists (e.g. metoclopramide, veralipride) and beta-adrenergic receptor antagonists (beta-blockers) clearly carry high potential for adverse reactions, while others such as tricyclic antidepressants seem more inconsistent in producing complications. Other drugs capable of causing adverse reactions include monoamine oxidase inhibitors, sympathomimetics (e.g. ephedrine) and certain peptide and corticosteroid hormones (e.g. corticotropin, glucagon and glucocorticoids). Risks associated with contraindicated medications are easily minimised by adoption of appropriate safeguards (e.g. adrenoceptor blockade). Without such precautions, the state of cardiovascular vulnerability makes some drugs and manipulations employed during surgical anaesthesia particularly dangerous. Problems arise most often when drugs or therapeutic procedures are employed in patients in whom the tumour is not suspected. In such cases, it is extremely important for the clinician to recognise the possibility of an underlying catecholamine-producing tumour and to take the most appropriate steps to manage and treat adverse events and clinical complications.

Pulmonary delivery of opioids as pain therapeutics

Pulmonary opioid delivery, on the basis of the fact that small molecular entities can be rapidly and completely absorbed from the peripheral lung, poses a unique opportunity for the treatment of severe (breakthrough) pain, which currently is treated with intravenous therapy. Early clinical studies involving inhaled opioids were focused on treatment of dyspnoea and not pain management, but they showed that inhalation of various opioid compounds is safe, even in severely ill patients. The advent of specialized and efficient pulmonary drug delivery systems has facilitated the evaluation of inhaled opioids, such as morphine and fentanyl, for management of severe pain associated with surgery or malignant disease. This review will summarize recent literature on the pharmacokinetics and pharmacodynamics of inhaled opioids and will discuss safety and efficacy in comparison to injection and other opioid dosage forms available for pain therapy. Finally, regulatory considerations will be discussed towards the approval of this new delivery paradigm for opioid drugs.

Evaluation of histamine release during constant rate infusion of morphine in dogs

OBJECTIVE

To evaluate histamine release and selected physiologic variables during constant rate infusion (CRI) of morphine in dogs.

ANIMALS

Five healthy, conscious, intact female dogs.

MATERIAL AND METHODS

Using a Latin square, repeated-measures design, dogs were randomly assigned to three treatment groups to receive a 4-hour CRI of saline (SAL), or a loading dose of morphine at 0.3 mg kg(-1) (LM), or 0.6 mg kg(-1) (HM), followed by an infusion of 0.17 mg kg(-1) hour(-1) (LM) and 0.34 mg kg(-1) hour(-1) (HM) respectively. Dogs received each of the three treatments at intervals of at least 7 days. Plasma histamine concentration, skin flushing, edema and wheals, heart rate and rhythm and non-invasive arterial blood pressure were measured before the loading dose and at 1, 2, 5, 15, 30, 60, 120, 180 and 240 minutes during the CRI, or at the time of occurrence.

RESULTS

The loading dose induced the highest histamine release in the HM group being statistically higher than the SAL group. The histamine release obtained in the LM group after the loading dose did not differ from SAL. During the infusion, plasma histamine levels were numerically higher in the LM group. Besides one dog that developed hypotension for 2 minutes after the loading dose in the HM group and one dog that showed occasional ventricular premature contractions during both morphine infusions, cardiovascular variables were similar among the three treatment groups.

CONCLUSIONS AND CLINICAL RELEVANCE

Both doses of morphine induced variable histamine release with minimal adverse cardiovascular effects in these conscious, healthy dogs. The plasma histamine levels obtained may be associated with significant hemodynamic changes in patients with limited cardiovascular reserve and sympathetic nervous tone.

In vitro evaluation of the potential role of sulfite radical in morphine-associated histamine release

BACKGROUND

Intravenous morphine use is associated with elevated histamine release leading to bronchoconstriction, edema and hemodynamic instability in some patients. This study evaluated the possibility that sulfite, which is present as a preservative in many morphine preparations, might contribute to histamine release in vitro.

RESULTS

The human mast cell line, HMC-1, was exposed to various morphine concentrations, in the absence of sulfite, under cell culture conditions. Clinically attained concentrations of morphine (0.018microg/ml and 0.45microg/ml) did not cause increased histamine release from mast cells. There was a significant increase in histamine release when the morphine concentration was increased by 1184-fold (668microg/ml morphine). Histamine release from mast cells exposed to morphine and/or sulfite required the presence of prostaglandin H synthetase. Histamine release in experiments using sulfite-containing morphine solutions was not statistically different from that observed in morphine-only solutions.

CONCLUSION

Sulfite in sulfite-containing morphine solutions, at concentrations seen clinically, is not responsible for histamine release in in vitro experiments of the human mast cell line, HMC-1. This does not preclude the fact that sulfite may lead to elevation of histamine levels in vivo.

Heroin insufflation as a trigger for patients with life-threatening asthma

STUDY OBJECTIVES

To determine the prevalence of self-reported, heroin-associated asthma symptoms among inner-city patients treated for life-threatening asthma, and to compare the rates of drug use between ICU patients with asthma and ICU control patients with diabetic ketoacidosis (DKA).

DESIGNS

Study 1 was a sequential case series of patients requiring ICU admission for asthma (January to June 1999). Study 2 was a retrospective, case-control study of drug use among asthma patients and control subjects with DKA requiring ICU care (1997 to 1998).

SETTING

Inner-city, public hospital ICU.

PATIENTS

Twenty-three patients (26 ICU admissions) with asthma (age range, 16 to 50 years) admitted to the ICU from January to June 1999, and 84 patients (104 ICU admissions) with asthma and 42 patients with DKA (age range, 15 to 50 years) admitted to the ICU during 1997 to 1998. Outcomes studied: Self-reported, heroin-associated exacerbations, history of heroin or cocaine use, and urine drug screen (UDS) results.

MEASUREMENTS AND RESULTS

In the sequential ICU admissions, 13 of 23 patients (56%) described asthma exacerbations associated with heroin insufflation. In the case-control study, asthmatics were significantly more likely to report heroin use (41.3% vs 12.5%; p = 0.006) and had a significantly higher prevalence of UDS results positive for opiates (60% vs 7%; p = 0.001) compared to subjects with DKA. The rates of cocaine use by history and UDS results did not differ significantly between the two groups.

CONCLUSIONS

At least since 1997, heroin insufflation is a common asthma trigger in this inner-city ICU and should be considered in the care of patients with life-threatening asthma.

Effects of hydromorphone or oxymorphone, with or without acepromazine, on preanesthetic sedation, physiologic values, and histamine release in dogs

OBJECTIVE

To compare hydromorphone with oxymorphone, with or without acepromazine, for preanesthetic sedation in dogs and assess changes in plasma concentration of histamine after drug administration.

DESIGN

Randomized clinical study.

ANIMALS

10 healthy mixed-breed dogs.

PROCEDURE

Dogs were treated IM with hydromorphone (group H), oxymorphone (group O), hydromorphone with acepromazine (group H/A), or oxymorphone with acepromazine (group O/A). Sedation score, heart rate, respiratory rate, systolic blood pressure, and oxygen saturation were recorded at baseline immediately after drug administration (T0) and every 5 minutes for 25 minutes (T25). Plasma histamine concentration was measured at baseline and T25.

RESULTS

Sedation was similar between groups H and 0 at all times. Sedation was significantly greater for groups H/A and O/A from T10 to T25, compared with other groups. Systolic blood pressure was significantly reduced at T25 in group H/A, compared with group H, and in group O/A, compared with group O. Prevalence of panting at T25 was 50% for groups H and O, compared with 20% for group H/A and 30% for group O/A. By T25, heart rate was significantly lower in all groups. Oxygen saturation was unaffected by treatment. Mean +/- SD plasma histamine concentration was 1.72 +/- 2.69 ng/ml at baseline and 1.13 +/- 1.18 ng/ml at T25. There was no significant change in plasma histamine concentration in any group.

CONCLUSIONS AND CLINICAL RELEVANCE

Hydromorphone is comparable to oxymorphone for preanesthetic sedation in dogs. Sedation is enhanced by acepromazine. Neither hydromorphone nor oxymorphone caused an increase in plasma histamine concentration.

Morphine-induced cardiovascular stimulation: the effects of two doses on healthy subjects

In humans, morphine induces hypotension, probably because of histamine liberation. Earlier animal studies have, however, suggested that morphine can induce immediate cardiovascular stimulation when given as a sole medication. The aim of this study was to evaluate the initial effects of morphine on circulation, oxygen consumption, and plasma histamine and catecholamine concentrations. Oxycodone was used as a reference drug. Eight healthy volunteers received, in a random, cross-over, double-blinded fashion: 0.07 mg/kg morphine (M1); 0.14 mg/kg morphine (M2); 0.14 mg/kg oxycodone (O); and placebo (P) as a 2-min IV injection for pain. Mean arterial blood pressure (MAP), heart rate (HR), and oxygen consumption (VO(2)) were recorded. Plasma histamine and catecholamine concentrations were determined. Both M1 and M2 elicited an initial, but transient, increase in MAP from 84 +/- 5 to 96 +/- 9 mm Hg (P < 0.05) and from 83 +/- 8 to 100 +/- 10 mm Hg (P < 0.05), respectively. A parallel increase in HR was also seen after M1 (from 62 +/- 12 to 70 +/- 10 bpm, P < 0.05) and M2 (from 67 +/- 9 to 78 +/- 8 bpm, P < 0.05). After M2, this was accompanied by a simultaneous increase in VO(2) from 295 +/- 39 mL/min to 322 +/- 61 mL/min (P < 0.05). After O, as well as P, no increase in MAP or HR was detected. Plasma histamine and catecholamine concentrations were not clearly affected by any of the treatments. We conclude that the immediate effect of morphine on the hemodynamics of healthy volunteers was stimulation, not hypotension. This effect was not seen in conjunction with oxycodone, a morphine-like mu-receptor agonist.

IMPLICATIONS

In this double-blinded, randomized study, we evaluated whether morphine could induce immediate cardiovascular stimulation, as seen previously in animal studies. In healthy volunteers, during a painful stimulus, morphine caused an initial, transient hemodynamic stimulation, accompanied by increased oxygen consumption, without detectable release of histamine or catecholamines into the plasma. Oxycodone caused only minor hemodynamic alterations.

Oral antihistamines reduce the side effects from rapid vancomycin infusion

Rapid infusion of vancomycin causes histamine-mediated side effects, hypotension, and rash, known as "red man syndrome." In this prospective, randomized, double-blind, placebo-controlled study, we examined the ability of oral antihistamines to attenuate three clinical end points: rash, hypotension, and vancomycin discontinuation, and we compared these findings with those of a similar study using IV antihistamines. Patients (ASA physical status I-III) who required vancomycin prophylaxis for elective arthroplasty received either oral antihistamines (diphenhydramine < or = 1 mg/kg and cimetidine < or = 4 mg/kg, n = 20) or placebo (n = 10) 1 h before rapid vancomycin infusion (1 g over 10 min). The vancomycin infusion was discontinued if the mean arterial blood pressure decreased by > or = 20% or if itching was intolerable for the patient. Clinically significant hypotension developed in no treated patients, compared with five (50%) patients in the placebo group (P = 0.001). Rapid infusion was stopped for one treated patient (5%) and for five (50%) patients in the placebo group (P = 0.004). Incidence (P = 0.011) and severity of rash (P = 0.015) were also reduced in treated patients. Peak histamine levels were increased but were similar for patients in both groups (mean +/- SD, 1.9+/-2.5 vs 1.6+/-2.4 ng/mL; P = 0.75). Oral antihistamines were as effective as IV antihistamines. In conclusion, oral H1 and H2 antihistamine pretreatment is a practical, safe, and inexpensive option to attenuate histamine-mediated side effects associated with rapid vancomycin infusion.

IMPLICATIONS

Clinicians often must administer vancomycin faster than the 1-h recommended time, which can cause "red man syndrome" (rash, itching, hypotension). Our randomized, double-blind, placebo-controlled study showed that oral H1 and H2 antihistamine pretreatment significantly reduced the histamine-related side effects of rapid vancomycin infusion.

Onset time, endotracheal intubating conditions, and plasma histamine after cisatracurium and vecuronium administration

Cisatracurium is a nondepolarizing muscle relaxant with a slow onset. We performed a prospective, randomized, double-blind clinical trial in 60 patients (ASA physical status I or II) to assess whether cisatracurium (0.15 or 0.25 mg/kg) or vecuronium (0.15 mg/kg), administered as a bolus immediately after induction of anesthesia with fentanyl and thiopental, would provide a faster onset time and better tracheal intubating conditions than previously reported. We sought to determine whether patients given muscle relaxants in this commonly used induction sequence would exhibit cutaneous, systemic, or chemical evidence of histamine release. Onset time of the relaxants was determined by using mechanomyography. Intubating conditions were scored on a defined interval scale by an anesthesiologist blinded to the relaxant administered. Heart rate and arterial blood pressure were measured noninvasively every minute from 10 min before to 5 min after the application of the muscle relaxant. Mean (+/- SD) onset times for 0.25 mg/kg cisatracurium (68.3 +/- 19.5 s) and for 0.15 mg/kg vecuronium (69.5 +/- 29.2 s) were significantly different from those in the 0.15 mg/kg cisatracurium group (105 +/- 41.2 s). The intubating conditions were better with the larger dose of cisatracurium or vecuronium (P < 0.03). Although plasma histamine levels were not statistically different among groups, levels >1 ng/mL were observed in 5 of 40 patients who received cisatracurium but in none of the 20 patients who received vecuronium. There were no significant hemodynamic differences among the groups. In a dose of 0.25 mg/kg, cisatracurium has as rapid an onset time as vecuronium 0.15 mg/kg, but the former shows evidence of histamine release.

IMPLICATIONS

Cisatracurium has been considered a drug with a relatively slow onset but that has the significant benefit of being devoid of chemically mediated histamine release. In this study, we describe an onset time faster than previously reported when cisatracurium was given immediately after thiopental. We also note that several patients had abnormal histamine levels after cisatracurium administration.

The lack of histamine release with cisatracurium: a double-blind comparison with vecuronium

A prospective, randomized, double-blind study was performed in 62 patients (ASA Classes I and II) treated with either 0.15 or 0.25 mg/kg cisatracurium or 0.15 mg/kg vecuronium administered as a rapid bolus. We wished to determine whether the muscle relaxants caused cutaneous, systemic, or chemical evidence of histamine release. Six minutes after induction of anesthesia with thiopental, patients received one of the muscle relaxants over 5 s. Plasma histamine levels were measured by radioimmunoassay after thiopental administration and 3 and 5 min after the administration of the relaxant. Additionally, plasma was assayed for tryptase, a marker of mast cell release. Cutaneous manifestations to both thiopental and the muscle relaxant were graded by an independent observer. Arterial blood pressure and heart rate were measured every minute. Although systolic and diastolic blood pressure decreased and heart rate increased significantly after thiopental administration (P < 0.0001), there were no further hemodynamic changes after either cisatracurium or vecuronium. One patient who received 0.25 mg/kg cisatracurium exhibited a slight elevation in plasma histamine level 5 min after hemodynamic changes. Cutaneous signs of histamine release were noted in five patients after thiopental administration (flush in four, erythema in one), but no further cutaneous reactions were observed after administration of either cisatracurium or vecuronium. We conclude that cisatracurium and vecuronium do not cause systemic or cutaneous histamine release. Tryptase levels showed no evidence of mast cell degranulation.

Administration of H1 and H2 antagonists for chemoprophylaxis: a double-blind, placebo-controlled study in healthy volunteers

A double-blind, placebo-controlled trial was performed to establish the duration of action of antihistamines and their ability to attenuate the adverse affects associated with histamine release. Thirty volunteers were assigned randomly to receive either placebo or a combination of the H1 blocker dimetindene maleate (0.1 mg/kg) and the H2 blocker cimetidine (5 mg/kg). A bolus dose of histamine (450 ng/kg) was given 15 minutes after antihistamine or placebo treatment and repeated after 2, 4, and 6 hours. Cardiovascular variables, plasma histamine levels, cutaneous manifestations, and objective and subjective signs and symptoms associated with histamine release were determined before and after each histamine injection. Although many of the signs of histamine release, including erythema and metallic taste, could be attenuated effectively for 6 hours with antihistamine treatment, the protection against histamine-induced flush and headache diminished after 2 hours. Statistically significant protection against histamine-mediated tachycardia persisted for only 2 hours. Antihistamine treatment significantly reduced the increase in plasma histamine levels after the first histamine injection but did not alter the levels after subsequent histamine injections. The currently recommended administration regimen for prophylaxis with antihistamines is insufficient to prevent histamine-mediated side effects, and additional doses may be required after 4 hours to achieve appropriate chemoprophylaxis.

Morphine-induced venodilation in humans

Morphine has been extensively used in the treatment of pulmonary edema, and its action is believed to be mediated in part by its ability to produce peripheral venodilation. This study investigated whether opiates produce venodilation in human hand veins and explored the underlying mechanism(s). Fifteen healthy volunteers (11 men and four women) were studied with use of the dorsal hand vein compliance technique. After preconstriction with the selective alpha 1-adrenergic receptor agonist phenylephrine, dose-response curves were constructed to (1) opiate receptor agonists morphine (1 to 30 micrograms/min) or fentanyl (0.07 to 1 microgram/min), (2) a combination of morphine and the mu-opiate receptor antagonist naloxone, and (3) morphine and a combination of histamine (H1 and H2) receptor antagonists. Infusion of morphine caused venodilation in a dose-dependent manner, whereas fentanyl did not produce venodilation. Coinfusion of naloxone and morphine impaired the venodilation only slightly. Coinfusion of the H1- and H2-antagonists completely abolished the venodilatory effect of morphine. These results suggest that the venodilatory effect of morphine is mediated through histamine release and that mu-opiate receptors have little or no involvement in this process.