A simulated car-driving study on the effects of acute administration of levocetirizine, fexofenadine, and diphenhydramine in healthy Japanese volunteers

Diphenhydramine: It is time to say a final goodbye

Diphenhydramine, once a pioneering antihistamine, is now overshadowed by second-generation antihistamines with similar efficacy and fewer adverse effects. Current data suggest that the adverse side-effect profile of diphenhydramine is higher among children and older adults. This has led to countries such as Germany and Sweden restricting access to first-generation antihistamines and societal guidelines advocating for the use of second-generation antihistamines. Despite its well-documented problematic therapeutic ratio, diphenhydramine remains available in over 300 formulations, most of which are over-the-counter. Based on a comprehensive evaluation of practice patterns and the prevalence and incidence of adverse clinical events, we believe that diphenhydramine has reached the end of its life cycle, and in its class of therapies it is a relatively greater public health hazard. We recommend it should no longer be widely prescribed or continue to be readily available over the counter.

Why fexofenadine is considered as a truly non-sedating antihistamine with no brain penetration: a systematic review

OBJECTIVE

Fexofenadine is a second-generation inverse agonist of H1-receptor of histamine which is highly selective with proven efficacy in relieving symptoms associated with allergic conditions. It has an additional benefit of not penetrating the blood-brain barrier and therefore do not induce sedation and not impair the cognitive function/psychomotor performance. This review aimed at providing evidence based on available controlled studies to reinforce the non-sedative property of fexofenadine for treating patients with allergic rhinitis and urticaria.

METHODS

We performed an electronic literature search using keywords such as fexofenadine, drowsiness, somnolence, sedation, fatigue, cognitive, impairment, psychomotor, driving performances, sleep, rapid eye movement, alertness, clinical study, in vitro study, in vivo study, and pharmacodynamics in the Embase search engine. The review included randomized controlled trials, review articles, systematic reviews, and meta-analyses, together with post-marketing analysis conducted in healthy subjects and patients with allergy and were focused on comparing the antihistaminic potential or safety of fexofenadine with other antihistamines or placebo.

RESULTS

Positron emission tomography (PET) and proportional impairment ratio (PIR) data along with other objective tests from various studies confirmed the non-sedative property of fexofenadine. Results of brain H1-receptor occupancy (H1RO) obtained from PET showed no H1RO by fexofenadine, the receptor which is known to cause sedation of H1 antihistamines. Most studies calculating PIR value as 0 showed fexofenadine to be a non-impairing oral antihistamine regardless of dose. Clinical trials in adults and children showed fexofenadine to be well tolerated without sedative effect or impairment of cognitive/psychomotor function even at higher than recommended doses.

CONCLUSION

Published literature based on various parameters and clinical trials conducted for evaluating the effect of fexofenadine on sedation and central nervous system shows fexofenadine is both clinically effective and non-sedating.

Potential risk of driving performance under combined conditions of taking second-generation antihistamines and attending calls using a hands-free function

OBJECTIVE

Although second-generation antihistamines have reduced sedation-related side effects compared to first-generation antihistamines, sedation may still impair motor vehicle driving performance. Moreover, receiving/making phone calls using a hands-free function can negatively affect driving performance. Therefore, herein, driving performance was evaluated using a driving simulator to gain insights into the hazards of driving by combining second-generation antihistamines and a calling task, i.e., simulated calls using a hands-free function.

METHODS

In this study, 20 subjects drove in a driving simulator in the absence or presence of a calling task while taking or not taking second-generation antihistamines. Driving performances for nonemergency and emergency events were determined, and a comparative analysis of intra-individual variability when taking and not taking second-generation antihistamines was conducted.

RESULTS

First, when nonemergency and emergency were examined in the absence of a calling task, no significant difference in driving performance was observed between taking and not taking second-generation antihistamines. Next, when the nonemergency event was examined in the presence of a calling task, no significant difference in driving performance was observed between taking and not taking second-generation antihistamines. However, when the emergency event was examined in the presence of a calling task, a significant difference in driving performance was observed between taking and not taking second-generation antihistamines, thus resulting in reduced driving performance.

CONCLUSIONS

The new system with added calling tasks allowed the extraction of the potential risks of driving performance of second-generation antihistamines that may have been previously overlooked. This study suggests that pharmacists and other healthcare professionals may need to instruct people taking any second-generation antihistamine to focus on driving and not on subtasks that require cognitive load such as talking while driving.

Psilocybin for alcohol use disorder: Rationale and design considerations for a randomized controlled trial

Several lines of evidence suggest that classic psychedelics (5-HT_2A receptor agonists or partial agonists) such as psilocybin might facilitate behavior change in individuals with substance use disorders. We conducted a multi-site, double-blind, randomized controlled trial (RCT) to assess the effects of psilocybin-assisted psychotherapy in alcohol-dependent volunteers. In addition to a structured 12-week psychotherapy platform, participants (n = 96) were randomly assigned (1:1) to receive either oral psilocybin or an active placebo (oral diphenhydramine) in each of two dosing sessions (at weeks 4 and 8). Initial doses were 25 mg/70 kg psilocybin or 50 mg diphenhydramine, which could be increased in the second session depending on initial response. The psychotherapy platform combined evidence-based, manualized therapy for alcohol dependence with a supportive context for the dosing sessions. All participants were followed in the RCT through week 36. At the end of the RCT, participants who still met safety criteria were offered an open-label psilocybin session. Data collected at screening, baseline and throughout the study included: demographics, measures of alcohol use, subjective response to psilocybin and diphenhydramine, and safety measures. The primary outcome was the proportion of heavy drinking days during the 32 weeks after the first dosing session (i.e., between week 4 and week 36). Secondary outcomes included safety, additional measures of drinking (e.g., abstinence, drinking days, etc.), craving, self-efficacy, and acute effects. We will also explore moderators and mediators of the primary outcome. The primary outcomes will be published elsewhere. In this paper, we describe the protocol and rationale for our design decisions.

Insights into urticaria in pediatric and adult populations and its management with fexofenadine hydrochloride

OBJECTIVE

The present narrative review provides a comprehensive update of the current knowledge on urticaria, both in adult and pediatric populations, and on the safety and efficacy of fexofenadine hydrochloride (HCl) as a treatment option.

DATA SOURCE

A literature search was conducted on Embase and Medline.

STUDY SELECTION

Clinical studies published in English and published between 1999 and 2020 were selected.

RESULTS

Although the exact pathogenesis of urticaria is not fully understood, multiple pathways of mast cell activation are discussed to explain the existence of phenotypically different clinical manifestations of urticaria. An overview of the worldwide prevalence of chronic urticaria, including disease burden and patient's quality of life is provided. The impact of urticaria on patient's life differs on the basis of whether its form is acute or chronic, but pharmacological approaches are most often needed to control the disabling symptoms. A summary of the current management of urticaria recommended by different guidelines across countries (Global; European; American; Australian; Asian; Japanese) is presented. Non-sedating, second-generation H₁-antihistamines are the preferred choice of treatment across several guidelines worldwide. Herein, the efficacy and safety of fexofenadine HCl, a representative second-generation H₁-antihistamine approved for the treatment of urticaria, is discussed. The occurrence of urticaria manifestations in COVID-19 patients is also briefly presented.

CONCLUSION

The burden of acute and chronic urticaria is high for patients. Second generation anti-histamines such as fexofenadine HCl can help managing the symptoms.

Trends in the use of antihistamines with reference to drivers between 2015 and 2019: A population-based registry analysis

BACKGROUND

First-generation antihistamines are considered driving-impairing medicines (DIM), while second- and third-generation antihistamines are relatively safe for driving.

OBJECTIVES

The aim of this study was to know the trend of consumption of antihistamines and other DIMs in Spain between 2015 and 2019.

METHODS

This is a population-based registry study. The population distribution by age and gender has been taken into account, as well the treatment duration with these medicines and the concomitant use of other DIMs. Adjusted consumption for licensed drivers is also presented.

RESULTS

Between 2015 and 2019, antihistamines were dispensed to 12.1% of the population and 9.25% of drivers. Oral antihistamines are the most consumed with 85.83%, and generally more used by women than men. Regardless of systemic antihistamines, the second-generation were the most consumed (8.9%) followed by the third-generation (2.07%) and the first-generation (0.61%). Subacute use was predominant in second -generation antihistamines (4.96%) and third-generation (1.26%), while acute use was predominant in third-generation antihistamines. On the other hand, only 0.36% of the population consumed antihistamines daily. The concomitant use of antihistamines with other DIMS was considerable, especially anxiolytics, opioids, other analgesics and antipyretics and antidepressants. The results in drivers were similar than in the general population.

CONCLUSIONS

The use of antihistamines has increased in recent years, however, in Spain, the use of less sedatives predominates, which is safe for driving. Finally, it is important to consider that concomitant use with other DIMs was frequent, which may affect the fitness to drive.

Intravenous Cetirizine Versus Intravenous Diphenhydramine for the Treatment of Acute Urticaria: A Phase III Randomized Controlled Noninferiority Trial

STUDY OBJECTIVE

Acute urticaria is a frequent presentation in emergency departments (EDs), urgent care centers, and other clinical arenas. Treatment options are limited if diphenhydramine is the only intravenous antihistamine offered because of its short duration of action and well-known adverse effects. We evaluate cetirizine injection, the first second-generation injectable antihistamine, for acute urticaria in this multicenter, randomized, noninferiority, phase 3 clinical trial.

METHODS

Adult patients presenting to EDs and urgent care centers with acute urticaria requiring an intravenous antihistamine were randomized to either intravenous cetirizine 10 mg or intravenous diphenhydramine 50 mg. The primary endpoint was the 2-hour pruritus score change from baseline, with time spent in treatment center and rate of return to treatment centers as key secondary endpoints. Frequency of sedation and anticholinergic adverse effects were also recorded.

RESULTS

Among 262 enrolled patients, the 2-hour pruritus score change from baseline for intravenous cetirizine was statistically noninferior to that for intravenous diphenhydramine (-1.6 versus -1.5; 95% confidence interval -0.1 to 0.3), and in favor of cetirizine. Treatment differences also favored cetirizine for mean time spent in treatment center (1.7 versus 2.1 hours; P=.005), return to treatment center (5.5% versus 14.1%; P=.02), lower change from baseline sedation score at 2 hours (0.1 versus 0.5; P=.03), and adverse event rate (3.9% versus 13.3%).

CONCLUSION

Intravenous cetirizine is an effective alternative to intravenous diphenhydramine for treating acute urticaria, with benefits of less sedation, fewer adverse events, shorter time spent in treatment center, and lower rates of revisit to treatment center.

Updated guidelines for intravenous contrast use for CT and MRI

Intravenous (IV) contrast material is used extensively for CT and MRI scans done in emergency departments (ED). Its use is essential to make many critical diagnoses in ED patients. While adverse reactions can occur, newer research has added to our knowledge of IV contrast media tolerance and safety leading to improved and more liberal guidelines for intravenous contrast use. The updated information described in this review article indicates how intravenous contrast can be used safely in more patients, more expeditiously and with fewer precautions than with prior guidelines. This review article explains the basis for the new recommendations for intravenous contrast material use and describes indicated precautions and preparations to avoid adverse reactions for iodinated agents used for CT and gadolinium agents for MRI.

Antihistamine effects and safety of fexofenadine: a systematic review and Meta-analysis of randomized controlled trials

Background

As a new generation antihistamine, fexofenadine has been widely used in allergic diseases. However, there is still a lack of collective evidence regarding the antihistamine effects and safety profiles of fexofenadine relative to other antihistamine drugs and placebo. Therefore, we aimed to systematically evaluate the antihistamine effects and safety of fexofenadine.

Methods

An electronic literature search of randomized controlled trials (RCTs) was performed using Embase, Cochrane and PubMed from establishment to January 1st, 2018. RCTs comparing the antihistamine effects or safety (adverse events, sedative effects, and cognitive/psychomotor function) of fexofenadine with either other antihistamines or placebo for healthy subjects and patients with allergy were selected.

Results

Fifty-one studies of 14,551 participants met the inclusion criteria. When compared with the first-generation antihistamines, fexofenadine produced significantly lower adverse events frequency (OR = 0.446; 95% CI: 0.214 to 0.929, P = 0.031), significantly lower sedative effects frequency (OR = 0.265; 95% CI: 0.072 to 0.976, P = 0.046) and significantly less change of all cognitive/psychomotor function. When compared with the second-generation antihistamines, fexofenadine produced significantly marginal sedative effects (OR = 0.59; 95% CI, 0.38 to 0.93; P = 0.02) and significantly less change of most of the cognitive/psychomotor function. When compared with placebo, fexofenadine produced more significant antihistamine effects.

Conclusions

Fexofenadine has a positive antihistamine effect, which is probably no worse than the second-generation antihistamines. Fexofenadine probably has a favorable safety profile, which is more likely better than that of the first-generation antihistamines. There is lack of data to support that fexofenadine has a better overall safety profile compared to the second-generation antihistamines, however, some presently available evidence on sedative effects and certain aspects of cognitive/psychomotor function favors fexofenadine. Therefore, fexofenadine may be worthy of recommendation for safety related workers.

Effects of levocetirizine and diphenhydramine on regional glucose metabolic changes and hemodynamic responses in the human prefrontal cortex during cognitive tasks

OBJECTIVE

Antihistamines often have sedative side effects. This was the first study to measure regional cerebral glucose (energy) consumption and hemodynamic responses in young adults during cognitive tests after antihistamine administration.

METHODS

In this double-blind, placebo-controlled, three-way crossover study, 18 healthy young Japanese men received single doses of levocetirizine 5 mg and diphenhydramine 50 mg at intervals of at least six days. Subjective feeling, task performances, and brain activity were evaluated during three cognitive tests (word fluency, two-back, and Stroop). Regional cerebral glucose consumption changes were measured using positron emission tomography with [¹⁸ F]fluorodeoxyglucose. Regional hemodynamic responses were measured using near-infrared spectroscopy.

RESULTS

Energy consumption in prefrontal regions was significantly increased after antihistamine administration, especially diphenhydramine, whereas prefrontal hemodynamic responses, evaluated with oxygenated hemoglobin levels, were significantly lower with diphenhydramine treatment. Stroop test accuracy was significantly impaired by diphenhydramine, but not by levocetirizine. There was no significant difference in subjective sleepiness.

CONCLUSIONS

Physiological "coupling" between metabolism and perfusion in the healthy human brain may not be maintained under pharmacological influence due to antihistamines. This uncoupling may be caused by a combination of increased energy demands in the prefrontal regions and suppression of vascular permeability in brain capillaries after antihistamine treatment. Further research is needed to validate this hypothesis.