Benzalkonium chloride in nasal decongestive sprays has a long-lasting adverse effect on the nasal mucosa of healthy volunteers

Pulmonary Toxicity of Benzalkonium Chloride

The available toxicity data of benzalkonium chloride (BKC) clearly shows that it is toxic; however, the weight of evidence favors the view that at doses encountered in nasally and orally inhaled pharmaceutical preparations it is well tolerated. The adverse toxicological data predominantly come from in vitro and animal studies in which doses and exposure periods employed were excessive in relation to the clinical doses and their posology and, therefore, not directly applicable to the clinic. The conflict between the in vitro and animal data and the clinical experience can be reconciled by understanding some of the physicochemical properties of BKC, the nasal and respiratory tract microenvironments, the doses used, and the posology.

Exposure to common quaternary ammonium disinfectants decreases fertility in mice

Quaternary ammonium compounds (QACs) are antimicrobial disinfectants commonly used in commercial and household settings. Extensive use of QACs results in ubiquitous human exposure, yet reproductive toxicity has not been evaluated. Decreased reproductive performance in laboratory mice coincided with the introduction of a disinfectant containing both alkyl dimethyl benzyl ammonium chloride (ADBAC) and didecyl dimethyl ammonium chloride (DDAC). QACs were detected in caging material over a period of several months following cessation of disinfectant use. Breeding pairs exposed for six months to a QAC disinfectant exhibited decreases in fertility and fecundity: increased time to first litter, longer pregnancy intervals, fewer pups per litter and fewer pregnancies. Significant morbidity in near term dams was also observed. In summary, exposure to a common QAC disinfectant mixture significantly impaired reproductive health in mice. This study illustrates the importance of assessing mixture toxicity of commonly used products whose components have only been evaluated individually.

Physiology and pathophysiology of respiratory mucosa of the nose and the paranasal sinuses

In this review, anatomy and physiology of the respiratory mucosa of nose and paranasal sinuses are summarized under the aspect of its clinical significance. Basics of endonasal cleaning including mucociliary clearance and nasal reflexes, as well as defence mechanisms are explained. Physiological wound healing, aspects of endonasal topical medical therapy and typical diagnostic procedures to evaluate the respiratory functions are presented. Finally, the pathophysiologies of different subtypes of non-allergic rhinitis are outlined together with treatment recommendations.

Nasal obstruction as a drug side effect

Nasal obstruction is a common symptom of various diseases, allergies, and structural deformities and a ‘stuffy nose’ is one of the most common reasons that patients seek a physician’s aid. Drugs that affect the autonomic nervous system are also expected to have a vasoactive effect on the nose. Nasal obstruction in the absence of infectious rhinitis or allergic symptoms may be due to drug use. With the chronic use of a medication, nasal obstruction can change over time and can be underestimated. Very little is known about this topic and very few publications to date solely devoted to drug-induced rhinitis. To prevent complications, obvious nasal obstruction due to drug intake should be treated with appropriate medication(s) or surgical intervention(s).

New aspects of the Slug Mucosal Irritation assay: predicting nasal stinging, itching and burning sensations

Stinging, itching and/or burning (SIB) sensations cannot be detected by animal tests or in vitro models. In the past, the Slug Mucosal Irritation (SMI) assay demonstrated a relation between an increased mucus production in slugs and an elevated incidence of SIB sensations in humans. A new 1-day SMI test procedure was developed focusing on the prediction of these short-term sensations. The objective of this study was to verify whether this new procedure is capable predicting mucosal tolerance of several marketed nasal formulations using the slug Arion lusitanicus. Irritation and tissue damage were quantified with a 5-day repeated exposure study by means of the mucus produced and proteins and enzymes released. The new protocol predicted SIB sensations by means of mucus production. The effects of six liquid nasal formulations were tested with both protocols, while five physiologic saline solutions were only tested with the new protocol to optimize it. None of the tested liquid nasal formulations resulted in tissue damage; however, exposure to the different formulations had a clear effect on the mucus production of the slugs and moderate discomfort was observed in some cases. These effects were due to the active ingredient, the presence of benzalkonium chloride as a preservative or the hyperosmolality of the formulation. For the most part results agreed with clinical data found in literature. It was concluded that the SMI assay, and the new 1-day protocol in particular, is a good tool to predict nasal clinical discomfort.

Comparative toxicity of preservatives on immortalized corneal and conjunctival epithelial cells

PURPOSE

Nearly all eye drops contain preservatives to decrease contamination. Nonpreservatives such as disodium-ethylene diamine tetra-acetate (EDTA) and phosphate-buffered saline are also regularly added as buffering agents. These components can add to the toxicity of eye drops and cause ocular surface disease. To evaluate the potential toxicity of these common components and their comparative effects on the ocular surface, a tissue culture model utilizing immortalized corneal and conjunctival epithelial cells was utilized.

METHODS

Immortalized human conjunctival and corneal epithelial cells were grown. At confluency, medium was replaced with 100 microL of varying concentrations of preservatives: benzalkonium chloride (BAK), methyl paraben (MP), sodium perborate (SP), chlorobutanol (Cbl), and stabilized thimerosal (Thi); varying concentrations of buffer: EDTA; media (viable control); and formalin (dead control). After 1 h, solutions were replaced with 150 microL of MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazonium bromide). After 4 h, solutions decanted, 100 microL of acid isopropanol added, and the optical density determined at 572 nm to evaluate cell viability.

RESULTS

Conjunctival and corneal cell toxicity was seen with all preservatives. Depending upon concentration, BAK exhibited from 56% to 89% toxicity. In comparison, Cbl exhibited from 50% to 86%, MP from 30% to 76%, SP from 23% to 59%, and Thi from 70% to 95%. EDTA with minimal toxicity (from 6% to 59%) was indistinguishable from SP.

CONCLUSIONS

Generally, the order of decreasing toxicity at the most commonly used concentrations: Thi (0.0025%) > BAK (0.025%) > Cbl (0.25%) > MP (0.01%) > SP (0.0025%) approximately EDTA (0.01%). Even at low concentration, these agents will cause some degree of ocular tissue damage.

Formulation considerations of intranasal corticosteroids for the treatment of allergic rhinitis

OBJECTIVE

To examine how various aspects of an intranasal corticosteroid (INS) formulation may influence the efficacy, tolerability, and patient preference and adherence to INS therapy.

DATA SOURCES

A PubMed search of the literature was conducted for studies on allergic rhinitis published between January 1977 and January 2006 using the keywords intranasal corticosteroid, preservatives, benzalkonium chloride, and tonicity.

STUDY SELECTION

Prospective studies, retrospective studies, and case reports were selected for inclusion in this review.

RESULTS

Currently available INSs are effective first-line treatments for allergic rhinitis. Differences in patient preference for a particular INS are largely attributable to sensory attributes of the nasal spray, which arise from characteristics of the formulation. Additives and preservatives can cause tolerability issues by irritating the mucosal membranes and causing nasal drying, or they can confer an unpleasant odor or taste to an INS formulation. The relative osmotic pressure, or tonicity, of an INS can modulate nasal absorption and retention, thereby potentially influencing the clinical efficacy. Characteristics such as delivery device and spray volume can affect a patient's perception and experience with a particular INS. Newer INSs, such as ciclesonide, are in development for the treatment of allergic rhinitis, and consideration of the formulation characteristics of these agents is an important part of the development process.

CONCLUSIONS

INSs are an effective treatment option for patients with allergic rhinitis; however, there is room for formulation improvement. Optimization of formulation may increase the efficacy, tolerability, and patient preference and adherence to INSs.

Rhinitis medicamentosa: a review of causes and treatment

Rhinitis medicamentosa (RM) is a drug-induced, nonallergic form of rhinitis that is associated with prolonged use of topical vasoconstrictors, i.e. local decongestants. Symptoms are exacerbated by the preservative benzalkonium chloride (BKC) in the nasal preparations. Nasal stuffiness is caused by rebound swelling of the mucosa when the decongestive effect of the drug has disappeared. To alleviate this symptom, patients gradually start using larger doses of the vasoconstrictor more frequently. In many cases, the patient is unaware of the condition, thus entering a vicious circle of self-treatment. Careful questioning is required during consultation to establish diagnosis. The pathophysiology of the condition is unclear; however, vasodilatation and intravascular edema have both been implicated. Management of RM requires withdrawal of topical decongestants to allow the damaged nasal mucosa to recover, followed by treatment of the underlying nasal disease. Topical corticosteroids such as budesonide and fluticasone propionate should be used to alleviate rebound swelling of the nasal mucosa. Where possible, avoiding exposure to BKC is recommended.

Immediate effect of benzalkonium chloride in decongestant nasal spray on the human nasal mucosal temperature

Benzalkonium chloride is a preservative commonly used in nasal decongestant sprays. It has been suggested that benzalkonium chloride may be harmful to the nasal mucosa. Decongestion with the vasoconstrictor xylometazoline containing benzalkonium chloride has been shown to cause a significant reduction of the nasal mucosal temperature. The purpose of the present study was to determine the short-term influence of xylometazoline nasal spray with and without benzalkonium chloride on the nasal mucosal temperature. Healthy volunteers (30) were included in the study. Fifteen volunteers received xylometazoline nasal spray (1.0 mg/mL) containing benzalkonium chloride (0.1 mg/mL) and 15 age-matched subjects, received xylometazoline nasal spray without benzalkonium chloride. Using a miniaturized thermocouple the septal mucosal temperature was continuously measured at defined intranasal detection sites before and after application of the nasal spray. The mucosal temperature values did not significantly differ between the group receiving xylometazoline containing benzalkonium chloride and the group receiving xylometazoline spray without benzalkonium chloride before and after decongestion (P > 0.05). In both study groups septal mucosal temperatures significantly decreased after decongestion (P < 0.05) because of a reduction of the nasal mucosal blood flow following vasoconstriction. This study indicates that benzalkonium chloride itself does not seem to influence nasal blood flow and nasal mucosal temperature in topical nasal decongestants.

[Tolerance and effectiveness of oxymetazoline and xylometazoline in treatment of acute rhinitis]

BACKGROUND

Local alpha-sympathomimetics in hydrous solution are well known in the therapy of acute rhinitis and sinusitis. However, added preservatives like benzalkonium chloride have a negative effect on compatibility.

PATIENTS AND METHOD

A total of 307 patients with acute rhinitis entered the study. The treatment with oxymetazoline with preservative, oxymetazoline without preservative and xylometazoline with preservative was evaluated.

RESULTS

This randomised, double-blind, multi-centered, verum-controlled tolerance study confirmed that the local sympathomimetics oxymetazoline and xylometazoline are well tolerated in the treatment of acute rhinitis. When evaluated according to the parameters "feeling of dryness in nasal mucosa" and "burning sensation", the Nasivin sanft 0.05% spray, which contains the active agent oxymetazoline without preservatives, proved to be considerably superior to preparations containing the preservative benzalkonium chloride.

CONCLUSION

Preparations without preservatives should be the preferred choice of treatment for acute rhinitis.

Safety review of benzalkonium chloride used as a preservative in intranasal solutions: an overview of conflicting data and opinions

BACKGROUND

For most multiuse aqueous nasal, ophthalmic, and otic products, benzalkonium chloride (BKC) is the preservative of choice. The American College of Toxicology has concluded that BKC can be safely used as an antimicrobial agent at concentrations up to 0.1%. BKC has been in clinical use since 1935 and is contained in a wide variety of prescription and over-the-counter products. However, over the past several years there have been conflicting reports of damage to human nasal epithelia and/or exacerbation of rhinitis medicamentosa associated with intranasal products containing BKC.

OBJECTIVE

We sought to review the published literature and determine whether there is sufficient, clinically significant data that would confirm that intranasal products containing BKC are likely to damage human nasal epithelia or exacerbate rhinitis medicamentosa.

METHODS

A literature search was conducted for in vivo and in vitro studies that evaluated the effects of BKC on human nasal epithelia.

RESULTS

A total of 18 studies (14 in vivo, 4 in vitro) were identified that evaluated short- and long-term exposure of concentrations of BKC in concentrations ranging from 0.00045% to 0.1%. Eight studies, including a 6-month and 1-year long-term treatment study, demonstrated no toxic effects associated with BKC, indicating that BKC was neither harmful to nasal tissue nor prone to exacerbate rhinitis medicamentosa. Furthermore, of the 10 studies that concluded that BKC resulted in degenerative changes in human nasal epithelia (eg, ciliary beat frequency, ciliary morphology, mucociliary clearance, epithelial thinning and/or destruction) or that BKC exacerbates rhinitis medicamentosa, only 2 (it was 2 according to the Results section) of these studies were supported by statistically significant differences between BKC and placebo or active control groups were compared. It is important to note that in both of these studies, the protocol incorporated the use or oxymetazoline in some or all of the subjects. Oxymetazoline is associated with rhinitis medicamentosa.

CONCLUSION

Intranasal products containing the preservative BKC appear to be safe and well tolerated for both long- and short-term clinical use.

Benzalkonium chloride as a preservative in nasal solutions: re-examining the data

Recent studies have suggested that benzalkonium chloride (BKC), an antimicrobial agent used as a preservative in nasal sprays, lacks deleterious effects on the nasal ciliated epithelium. Other data, including recent in vivo findings, suggest that BKC may, in fact, produce adverse clinical effects on human nasal tissue, including the aggravation of rhinitis medicamentosa. Toxic effects have also been reported. In light of the discrepancy between negative results and studies suggesting no safety concerns, we consider the possibility of problems in the design and methodology of some of the studies and in the interpretation of results. Clearly, further research is warranted to clarify the significance of conflicting findings. In the meantime, without conclusive data regarding BKC and the possibility of harmful effects, the use of nasal formulations without BKC might be a reasonable alternative.

Effects of benzalkonium chloride on innate immunity physiology of the human nasal mucosa in vivo

OBJECTIVE

Benzalkonium chloride (BC) is a preservative commonly used in nasal decongestant sprays. It has been suggested that BC may be harmful to the nasal mucosa. The present study, involving healthy volunteers, examines effects of BC on nasal mucosal end-organ functions.

METHODS

Isotonic saline and BC (0.1 mg/mL) were administered acutely to the nasal mucosa using a nasal pool device. Nasal symptoms were determined. Nasal lavage fluid levels of alpha2-macroglobulin and fucose were measured as indices of plasma exudation and glandular secretion, respectively. In addition, BC (0.1 mg/mL) was given as single actuations of 100 microL per nasal cavity three times daily for 10 days. The ability of histamine (0.4 mg/mL) to evoke nasal symptoms and plasma exudation responses was determined before and after the repeated BC administration series.

RESULTS

BC produced immediate nasal smart or pain (P < .05), but tolerance to this response developed by repeated administrations. BC increased nasal mucosal output of fucose (P < .05), whereas nasal lavage fluid levels of alpha2-macroglobulin were unaffected. Histamine produced significant symptoms and mucosal exudation of alpha2-macroglobulin (P values < .01), equally before and after the 10 days of BC exposure.

CONCLUSIONS

BC in dosages commonly used as preservative in nasal decongestant sprays produced short-term glandular secretion and nasal smart or pain. However, 10 days' frequent exposure to BC was not associated with untoward symptomatic effects, nor was a sensitive mucosal variable such as histamine-induced exudative responsiveness affected by this repeated exposure 1 BC.

Adverse effects of benzalkonium chloride on the nasal mucosa: allergic rhinitis and rhinitis medicamentosa

Prolonged, repeated use of nasal decongestants for symptomatic relief of allergic rhinitis often results in rhinitis medicamentosa (RM), a condition involving "rebound swelling" and additional congestion. Most decongestant sprays contain the preservative benzalkonium chloride (BKC), which causes toxic reactions in the nose, eyes, ears, and lungs, and may exacerbate the symptoms of allergic rhinitis. Recent studies demonstrate the effects of nasal sprays containing BKC or the decongestant oxymetazoline (OXY) in the development of RM. Using rhinostereometry, a technique that measures nasal mucosal swelling and nasal reactivity (with histamine challenge tests), prolonged use of OXY has been shown to induce nasal mucosal swelling and hyperreactivity. Sustained use of BKC alone induces nasal mucosal swelling and, in combination with OXY, BKC appears to have a long-term adverse effect on nasal mucosa. Its presence may also contribute to the RM resulting from overuse of decongestant sprays. Additional research is needed to confirm the deleterious effects of BKC in nasal products. However, these potential effects may be points of clinical differentiation in the treatment of allergic rhinitis and prevention of RM.

Nasal mucociliary clearance as a factor in nasal drug delivery

The nasal mucociliary clearance system transports the mucus layer that covers the nasal epithelium towards the nasopharynx by ciliary beating. Its function is to protect the respiratory system from damage by inhaled substances. Impairment of nasal mucociliary clearance can result in diseases of the upper airways. Therefore, it is important to study the effects of drugs and drug excipients on nasal mucociliary clearance. A large number of methods are used to assess mucociliary clearance. These methods study the effects of drug and excipients on the mucociliary system in vitro or in vivo in animals and humans. In some cases, the results of different in vitro and in vivo measurements do not correlate well. In vitro methods, especially ciliary beat frequency measurements, have been demonstrated to be valuable tools for toxicity screening. However, in vivo studies are essential to confirm the safety of nasal drug formulations. Nasal mucociliary clearance also has implications for nasal drug absorption. Drugs are cleared rapidly from the nasal cavity after intranasal administration, resulting in fast systemic drug absorption. Several approaches are discussed to increase the residence time of drug formulations in the nasal cavity, resulting in improved nasal drug absorption. However, more experimental evidence is needed to support the conclusion that this improved absorption is caused by a longer residence time of the nasal drug formulation.

Rhinitis medicamentosa: aspects of pathophysiology and treatment

With modern vasoconstrictors, such as oxy- and xylometazoline, the risk of developing rhinitis medicamentosa (RM) has been considered to be small or even nonexistent. However, recent studies have shown that overuse of these drugs may result in rebound congestion, nasal hyperreactivity, tolerance, and histologic changes of the nasal mucosa. Using rhinostereometry, it has also been shown that the long-term use of the preservative benzalkonium chloride (BKC) in oxymetazoline nasal spray accentuates the severity of rhinitis medicamentosa in healthy volunteers. A nasal decongestant spray composed of a combination of vasoactive substances and BKC has a long-term adverse effect on the nasal mucosa. BKC alone induces mucosal swelling after 30 days use of the nasal spray in healthy subjects, unlike placebo. According to the author, rhinitis medicamentosa can be defined as a condition of nasal hyperreactivity, mucosal swelling, and tolerance that is induced, or aggravated, by the overuse of topical vasoconstrictors with or without a preservative. An adequate treatment of these patients consists of a combination of vasoconstrictor withdrawal and a topical corticosteroid to alleviate the withdrawal process. The underlying nasal disorder must then be treated. Patients with rhinitis medicamentosa who overuse topical decongestants and are able to stop using such drugs should be careful about taking these drugs again, even for a few days. They must be informed about the rapid onset of rebound congestion upon repeated use in order to avoid the return of the vicious circle of nose-drop abuse.

The effects of topical nasal steroids on rat respiratory mucosa in vivo, with special reference to benzalkonium chloride

Fifty rats were treated with topical nasal steroids with and without the preservative benzalkonium chloride in their right nostril twice daily for 21 days, while the left nostrils were exposed to 0.9% NaCl. By cutting the noses serially in frontal sections, the structure of the mucosal lining of all parts of the nose could be investigated. Areas with squamous cell metaplasia were observed in all nostrils exposed to topical steroids containing benzalkonium chloride. Such alterations were not observed in any nasal cavities exposed to the topical nasal steroid without the preservative or to 0.9% NaCl. In conclusion, benzalkonium chloride appears to be potentially toxic to the mucosa in vivo.

One year follow-up of patients with rhinitis medicamentosa after vasoconstrictor withdrawal

The aim of the study was to systematically follow-up 10 patients with rhinitis medicamentosa for at least 1 year after vasoconstrictor withdrawal. During withdrawal of the decongestants the patients used budesonide nasal spray, 400 micrograms/day, for 6 weeks. The thickness of the nasal mucosa, the decongestive effect of oxymetazoline, and the histamine sensitivity were measured with rhinostereometry during the period. The thickness of the nasal mucosa and the symptom scores of nasal stuffiness were reduced considerably 6 and 12 months after vasoconstrictor withdrawal. The histamine sensitivity reflecting nasal hyperreactivity was still increased after 6 months, but not after 1 year. The decongestive effect of oxymetazoline increased after 6 months, indicating reversible tolerance. We conclude that when given adequate treatment and information about nose-drop overuse, all patients were able to stop using the vasoconstrictors and no one relapsed into a daily long-term overuse of vasoconstrictors during the 1-year follow-up period.

Effect on the nasal mucosa of long-term treatment with oxymetazoline, benzalkonium chloride, and placebo nasal sprays

A parallel, randomized, double-blind study was performed in 30 healthy subjects to investigate the effects on the nasal mucosa of a 1-month treatment with nasal sprays. Ten subjects received oxymetazoline nasal spray; 10 subjects used a nasal spray containing the preservative benzalkonium chloride, and the others were treated with a placebo nasal spray. The three variables that were studied --nasal mucosal swelling, symptom scores, and nasal reactivity-- were estimated by histamine challenge before and after 28 days of treatment. Rhinostereometry was used to measure nasal mucosal swelling and nasal reactivity. After 28 days of use, benzalkonium chloride spray alone induced an increase in nasal mucosal swelling. At the end of the month, the score for nasal stuffiness was significantly higher for the group treated with oxymetazoline than for those treated with benzalkonium chloride. Oxymetazoline nasal spray induced a pronounced increase in nasal reactivity, which was significantly greater than that induced in the placebo group. Long-term use of placebo and benzalkonium chloride nasal sprays also caused an increase in nasal reactivity, but not to the same extent as with the nasal sprays containing oxymetazoline. The authors concluded that long-term use of oxymetazoline induces a sensation of nasal stuffiness, which may be due to unconscious exaggeration of the degree of nasal stuffiness, induced nasal hyperreactivity, or a combination of both. These factors are probably the main reasons for the prolonged use of nasal decongestive sprays and the development of rhinitis medicamentosa. Benzalkonium chloride induces mucosal swelling, which explains why the presence of this preservative in a decongestant spray aggravates rhinitis medicamentosa.