Update on prescription and over-the-counter histamine inverse agonists in rhinitis therapy

Bilastine: a new antihistamine with an optimal benefit-to-risk ratio for safety during driving

INTRODUCTION

Rational selection of a second-generation H1-antihistamine requires efficacy and safety considerations, particularly regarding central nervous system (CNS) effects (cognitive and psychomotor function), potential for driving impairment, minimal sedative effects and a lack of interactions. This review evaluates the key safety features of the non-sedating antihistamine, bilastine, during driving and in preventing road traffic accidents.

AREAS COVERED

Among the second-generation H1-antihistamines, sedative effects which can affect cognitive and psychomotor performance, and possibly driving ability, may not be similar. Bilastine is absorbed rapidly, undergoes no hepatic metabolism or cytochrome P450 interaction (minimal drug-drug interaction potential), and is a substrate for P-glycoprotein (limiting CNS entry). Positron emission tomography showed that, compared with other second-generation H1-antihistamines, bilastine has the lowest cerebral histamine H1-receptor occupancy. Bilastine 20 mg once daily (therapeutic dose) is non-sedating, does not enhance the effects of alcohol or CNS sedatives, does not impair driving performance and has at least similar efficacy as other second-generation H1-antihistamines in the treatment of allergic rhinoconjunctivitis and urticaria.

EXPERT OPINION

Current evidence shows that bilastine has an optimal benefit-to-risk ratio, meeting all conditions for contributing to safety in drivers who need antihistamines, and hence for being considered as an antihistamine of choice for drivers.

The ARGA study with Italian general practitioners: prescriptions for allergic rhinitis and adherence to ARIA guidelines

BACKGROUND

General practitioners (GPs) are the healthcare professionals to whom patients with rhinitis firstly refer for their symptoms.

OBJECTIVE

In the present study, we assessed drug prescriptions for allergic rhinitis (AR) and evaluated prescriptive adherence to ARIA treatment guidelines.

METHODS

Data on 1379 AR patients were collected by 107 Italian GPs. Adherence to ARIA guidelines was evaluated according to AR severity classification.

RESULTS

AR was diagnosed by GPs as mild intermittent for 46.2% of patients, mild persistent for 26.6%, moderate-severe intermittent for 20.2%, and moderate-severe persistent for 7%; 43.7% of AR patients had concomitant asthma. The most frequently prescribed therapeutic groups were antihistamines (anti-H, 76%) and nasal corticosteroids (NCS, 46%). Anti-H were significantly used more often to treat AR alone than AR + asthma (85 vs. 68%, p < 0.001), whereas NCS were used more often to treat AR + asthma than AR alone (50 vs. 42%, p = 0.01). Among patients with only mild intermittent AR, 39% were prescribed combined therapy. Among patients with moderate-severe persistent AR, 30% of those with AR alone and 18% of those with AR + asthma were prescribed monotherapy based on anti-H. GPs were more compliant with ARIA guidelines while treating AR alone (57%) than AR + asthma (46%) patients. The adherence increased according to the severity grade and was satisfactory for moderate-severe persistent AR (89% for AR alone and 95% for AR + asthma).

CONCLUSIONS

Adherence to ARIA guidelines is satisfactory only for treatment of more severe patients, thus GPs often tend to treat patients independently from ARIA guidelines. Since prescription data only provide limited information to judge prescribing quality, some deviation from the gold standard are to be expected.

Immunological approaches for tolerance induction in allergy

Allergy is the consequence of an inappropriate inflammatory immune response generated against harmless environmental antigens. In allergic disorders such as asthma and rhinitis, the Th2 mediated phenotype is a result of loss of peripheral tolerance mechanisms. In cases such as these, approaches such as immunotherapy attempt to treat the underlying cause of allergic disease by restoring tolerance. Immunotherapy initiates many complex mechanisms within the immune system that result in initiation of innate immunity, activation of both cellular and humoral B cell immunity, as well as triggering T regulatory subsets which are major players in the establishment of peripheral tolerance. Though studies clearly demonstrate immunotherapy to be efficacious, research to improve this treatment is ongoing. Investigation of allergenicity versus immunogenicity, native versus modified allergens, and the use of adjuvant and modality of dosing are all current strategies for immunotherapy advancement that will be reviewed in this article.

Fexofenadine: biochemical, pharmacokinetic and pharmacodynamic properties and its unique role in allergic disorders

BACKGROUND

Fexofenadine is one of several second-generation H(1)-antihistamines approved for the treatment of various allergic disorders; however, it shows numerous unique properties that make it an optimal choice for many patients.

OBJECTIVE

To review the pharmacology, efficacy and safety of fexofenadine and the attributes differentiating it from other H(1)-antihistamines.

METHODS

We performed a literature search in PubMed/MEDLINE (1966 - March 2009) using the keywords fexofenadine, antihistamine, allergic rhinitis and chronic urticaria. We also reviewed data provided by the manufacturer in addition to reports from various governmental agencies.

RESULTS/CONCLUSIONS

Fexofenadine is devoid of sedative and anticholinergic effects and may offer equivalent or greater efficacy in treating allergic disorders compared with other currently available second-generation H(1)-antihistamines. In addition, fexofenadine may offer cost savings over other selected H(1)-antihistamines owing to its recent availability in generic form in the US.