The effect of inhaled ipratropium bromide alone and in combination with oral terfenadine on bronchoconstriction provoked by adenosine 5'-monophosphate and histamine in asthma.

The aim of this study was to investigate the effect of terfenadine, an antihistamine, 180 mg orally, the anticholinergic drug, ipratropium bromide (IB), 0.5 mg nebulized aerosol, the combination of these two drugs, and placebo tablets and aerosol on histamine- and adenosine 5'-monophosphate (AMP)-induced bronchoconstriction in a randomized, double-blind fashion. Airway response was evaluated as FEV1. After placebo, the geometric mean (GM) provocative concentration causing a 20% in FEV1 from the postsaline baseline value (PC20) for histamine and AMP was 0.63 and 5 mg/ml, respectively. Terfenadine displaced the FEV1 concentration-response curves obtained with both histamine (GM PC20 values increasing to 26.92 mg/ml) and AMP (GM PC20 values increasing to 26.7 mg/ml) to the right. IB had a small, but significant, protective effect against the fall in FEV1 produced by histamine and AMP, the GM PC20 values increasing to 1.69 and to 12.6 mg/ml, respectively. Terfenadine and IB in combination produced protection against histamine and AMP that was more than the production produced by either drug alone, the GM PC20 values increasing to 54.76 and 47.7 mg/ml, respectively. There was no correlation between degree of bronchodilatation induced by active treatments and concentration ratios for AMP or histamine. These data suggest that histamine release and vagal reflexes both contribute to AMP-induced bronchoconstriction in clinical asthma in man.     

Onset and duration of inhibition of ipratropium bromide nasal spray on methacholine-induced nasal secretions

We performed a randomized, double-blind, placebo-controlled cross-over study with two different concentrations of ipratropium bromide (Atrovent®) nasal spray to evaluate its onset and duration of inhibition. Twenty-four subjects with perennial rhinitis participated in the trial. Fifteen minutes to 12 hours after administration of ipratropium bromide (42 or 168 μg/nostril) or placebo nasal spray, methacholine challenges were performed and nasal secretion weights measured. After placebo administration the effect of methacholine remained unchanged over the 12-h-period. Both the 42 and 168 μg/nostril doses significantly inhibited the nasal hypersecretions induced by methacholine challenge within 15 min of treatment (P < 0.05). The 168 μg dose of ipratropium bromide continued to significantly reduce secretion weights through 6 hours, but the effectiveness of the 42 μg dose disappeared within 3 h. In addition to having a longer duration, the 168 μg/nostril dose produced approximately twice the inhibitory effect of the 42 μg dose.     

Effects of ipratropium bromide on bradykinin nasal provocation in chronic allergic rhinitis

Bradykinin (BK) induces albumin exudation and glandular secretion in chronic allergic rhinitis subjects. Since bradykinin may stimulate nociceptive sensory nerves, neural reflex arcs could contribute to the secretion process. Six chronic allergic rhinitis subjects received 1000nm bradykinin by unilateral nasal provocation using the method of Raphael et al. This dose induces optimal contralateral glandular secretion. Ipratropium bromide (80μg) or saline were applied topically before the challenges. Total protein, albumin, glycoconjugate, and lysozyme were measured in lavage fluids. On the ipsilateral side, bradykinin induced significant total protein, glycoconjugate, and albumin secretion. None of these were affected by ipratropium. On the contralateral side, total protein and glycoconjugates were increased by bradykinin, while albumin and lysozyme were not significantly affected. Ipratropium bromide completely ablated total protein and glycoconjugate secretion on the contralateral side indicating that cholinergic reflexes mediated the glandular secretion. In chronic allergic rhinitis, bradykinin directly stimulated albumin secretion, but also stimulates nociceptive neuron–parasympathetic nerve reflexes to induce glandular secretion. The reflex loop was apparent on the contralateral side to the unilateral bradykinin challenge. This loop induced mucoglycoconjugate, but not serous cell, secretion in chronic allergic rhinitis subjects and can be inhibited by iptratropium bromide.     

Effect of terfenadine and placebo on symptoms after nasal allergen provocation

Terfenadine (60 mg b.i.d.) was compared with placebo in a randomized, double-blind, cross-over study in twenty-three patients with birch pollen allergy. The patients were treated during two 7-day periods separated by a 2-week wash-out period during a season free from birch pollen. Nasal provocations with birch pollen extracts were made at study entry and after each treatment period. Blockage (rhinomanometry), secretion (weight) and sneezings (number) were compared between treatments. The results showed a significant inhibitory effect of terfenadine on secretion and sneezing, but no significant difference between treatments with regard to blockage. Terfenadine showed no signs of sedative properties or inhibition of salivation.     

Ipratropium bromide nasal spray 0.03% and beclomethasone nasal spray alone and in combination for the treatment of rhinorrhea in perennial rhinitis.

BACKGROUND: Perennial rhinitis is a common condition that affects up to 10% to 20% of the population. Multiple agents are frequently administered since no single agent provides complete relief. Studies assessing the benefit/risk of combined therapy are important especially for newly approved agents such as ipratropium bromide nasal spray 0.03%, a topical anticholinergic agent, approved specifically for the treatment of rhinorrhea in allergic and non-allergic perennial rhinitis. OBJECTIVE: To compare the efficacy and safety of the combined use of ipratropium bromide nasal spray 0.03% (42 microg per nostril tid) and beclomethasone dipropionate nasal spray (84 microg per nostril bid) against that of either active agent alone for the treatment of rhinorrhea. DESIGN: Multicenter, 6-week, double-blind, randomized active- and placebo-controlled, parallel trial. SETTING: Allergist and general practitioner clinical practices. PATIENTS: Five hundred thirty-three patients with perennial rhinitis (279 allergic and 274 non-allergic), 8 to 75 years of age, who had at least a mild degree of severity of rhinorrhea for a minimum of 2 hours per day during the 1 week screening period as well as congestion or sneezing also of at least mild severity. INTERVENTION: Either (1) ipratropium bromide nasal spray 0.03% (42 microg per nostril tid) plus beclomethasone dipropionate nasal spray (84 microg per nostril bid), (2) ipratropium bromide nasal spray 0.03% (42 microg per nostril tid) alone, (3) beclomethasone dipropionate nasal spray (84 microg per nostril bid) alone, or (4) vehicle [matching placebo nasal spray for the ipratropium bromide (2 sprays per nostril tid)] or beclomethasone dipropionate (2 sprays per nostril bid). MAIN OUTCOME MEASURE: Severity and duration of rhinorrhea, and patient and physician global assessment of control of rhinorrhea. RESULTS: Ipratropium bromide nasal spray plus beclomethasone nasal spray was more effective than either active agent alone or vehicle in reducing the average severity and duration of rhinorrhea during 4 weeks of treatment. The advantage of ipratropium bromide plus beclomethasone nasal spray was evident by the first day of combined treatment and continued throughout the 2-week treatment period. Ipratropium bromide nasal spray had a faster onset of action during the first week of treatment and reduced the duration of rhinorrhea more than beclomethasone. Beclomethasone nasal spray was more effective in reducing the severity of congestion and sneezing than ipratropium. In patients who had not responded well to a nasal steroid prior to participation in the study based on a questionnaire administered at screening, ipratropium bromide was as effective in the steroid non-responders as steroid responders, whereas beclomethasone was more effective in steroid responders. Combined active therapy was well tolerated with no increase in adverse events over that seen previously with ipratropium bromide or beclomethasone nasal spray alone. CONCLUSIONS: The combined use of ipratropium bromide nasal spray with beclomethasone dipropionate nasal spray is more effective than either active agent for the treatment of rhinorrhea, and does not result in a potentiation of adverse drug reactions. Ipratropium bromide nasal spray 0.03% alone should be considered in patients for whom rhinorrhea is the primary symptom, and its use in combination with a nasal steroid should be considered in patients where rhinorrhea is one of the predominant symptoms, or in patients with rhinorrhea not fully responsive to other therapy.     

Effect of terfenadine and budesonide on nasal symptoms, olfaction, and nasal airway patency following allergen challenge

The study investigated the effect of the oral H₁-blocker terfenadine on allergen challenge in subjects with nasal allergy in comparison with the topical steroid, budesonide. A randomized, placebo-controlled, double-blind, crossover study with 3 experimental days was performed outside the pollen season. Seventeen nonsmokers with hay fever 'symptoms, positive skin prick test, and RAST against timothy) were treated for 14 days before each experimental day, where the response to nasal challenge with four different concentrations of timothy was measured every 15 min for 6 h. The nasal cavity dimensions were measured by acoustic rhianometry and the olfactory function as the threshold for the sense of smell of butanol. Nasal symptoms were determined by questionnaires. Both terfenadine and budesonide dry powder had an effect on the hay fever symptoms during nasal pollen challenge. Terfenadine was more efficient than budesonide against histamine-mediated symptoms such as sneezing and itching. Budesonide increased nasal airway dimensions better than terfenadine ' P < 0.01). A marked effect of budesonide was seen 1-2 h after challenge, suggesting an effect on 'early late phase' reaction in the nose. In 7/17 subjects, a significant ' P < 0.05) improvement of olfactory function after budesonide treatment was seen. In conclusion, topical steroid 'budesonide) is superior to antihistamine 'terfenadine) in treatment of nasal congestion in hay fever, especially for the postchallenge reaction, and may, in some cases, relieve the decreased sense of smell during pollen challenge.     

Comparison of nebulized ipratropium bromide with salbutamol vs salbutamol alone in acute asthma exacerbation in children.

BACKGROUND: Despite multiple doses of beta2-agonists in the treatment of acute asthma exacerbation, significant residual airways obstruction often remains. OBJECTIVE: To determine whether the addition of inhaled ipratropium bromide to salbutamol provides improvement in lung function and clinical asthma symptoms in young children with acute asthma exacerbation. METHODS: This study was a prospective, double-blind randomized control trial of children aged 3 to 15 years who presented with an acute asthma exacerbation at the emergency department or outpatient clinic of Thammasat University Hospital, Pathumthani, Thailand, between September 2001 and February 2003. Subjects were randomized to receive 3 doses of nebulized salbutamol mixed with isotonic sodium chloride solution (control) or ipratropium bromide (treatment) every 20 minutes. Additional doses of salbutamol were given every 30 minutes as needed. Asthma outcome measures were evaluated 40, 70, 100, and 120 minutes after baseline. Primary outcomes were the differences in percent change in asthma clinical score and percent change in peak expiratory flow rate (PEFR) from baseline. Secondary outcomes included change in percent predicted PEFR. RESULTS: Of 74 children randomized and enrolled in the trial, 71 had complete data for analysis. Thirty-three children were in the control group and 38 were in the treatment group. Both the percent change in PEFR and the change in percent predicted PEFR at any time were higher in the treatment group, but these findings were not statistically significantly different. The number of subjects with at least a 100% percent predicted PEFR at any time point was greater in the treatment group. CONCLUSION: Although this study did not demonstrate a significant advantage in clinical score and PEFR, the trend toward additional effect of ipratropium bromide was consistent with previous studies.     

The influence of simvastatin alone or in combination with gemfibrozil on plasma lipids and lipoproteins in patients with type III hyperlipoproteinemia

Summary Nineteen adult patients with type III hyperlipoproteinemia (HLP) and homozygosity for apolipoprotein (apo) E2 were treated with the 3-hydroxy-3-methyl glutaryl coenzyme A (HMG CoA) reductase inhibitor simvastatin (20 or 40 mg per day) alone or in combination with the fibrate derivative gemfibrozil (450 mg per day) during a 30-week outpatient study. With the 20-mg dose (n = 19) the mean plasma cholesterol level decreased from 13.24±8.04 8.04 at baseline to 8.04±4.19 mmol/l (mean reduction 39.3%; P<0.05), and the mean plasma triglyceride level decreased from 13.47±19.22 to 7.84±7.71 mmol/l (–41.8%; NS); this was due to a decrease in very low density lipoprotein (VLDL) cholesterol from 8.95±8.64 to 4.94±4.24mmo1/l (–44.8%; NS), a decrease in low density lipoprotein (LDL) cholesterol from 3.54±0.93to 2.25 ± 0.59 mmol/l (–36.5%; P<0.01), and an increase in high density lipoprotein (HDL) cholesterol from 0.72±0.28 to 0.85±0.34 (+18.1%; NS). Thirteen patients were treated with 40 mg simvastatin per day. Under this regimen there was a further significant decrease in LDL cholesterol from 2.33±0.62 to 1.81±0.49 mmol/l (–22.3%; P<0.01). In six patients who remained hyperlipidemic on monotherapy combination drug therapy with simvastatin (40 mg per day) and gemfibrozil (450 mg per day) was given. Compared to simvastatin alone the addition of gemfibrozil further lowered plasma concentrations of total cholesterol by 14.9%, VLDL cholesterol by 23.5%, and triglycerides by 17.1%, although this was not statistically significant. No patient was discontinued from single or combination drug therapy, and no severe clinical or biochemical side effects were observed. The results of this study demonstrate the usefulness of simvastatin in the therapy of type III HLP and indicate that in individual patients who remain hyperlipidemic on monotherapy combination drug therapy with both of these drugs is effective in further reducing plasma concentrations of total cholesterol, VLDL cholesterol, and triglycerides. Although no patient in this investigation developed myopathy or rhabdomyolysis, combined fibrate-HMG CoA reductase inhibitor treatment should be considered only for severe forms of hyperlipidemia and for patients who do not respond sufficiently to mon-therapy of any of these drugs.Abbreviations Apo Apolipoprotein - CPK creatine phosphokinase - GGT gamma-glutamyl transpeptidase - HDL high density lipoproteins - HLP hyperlipoproteinemia - HMG CoA 3-hydroxy-3-methyl glutaryl coenzyme A - IDL intermediate density lipoproteins - LDL low density lipoproteins - TG triglycerides - VLDL very low density lipoproteins     

Protective effect of oral terfenadine and not inhaled ipratropium on adenosine 5'-monophosphate-induced bronchoconstriction in patients with COPD

BACKGROUND: Inhalation of adenosine 5'-monophosphate (AMP) causes bronchoconstriction in patients with asthma and in many patients with chronic obstructive pulmonary disease (COPD). In asthma, AMP-induced bronchoconstriction has been shown to be determined mainly by release of mast cell mediators, and possibly by vagal nerve stimulation, since oral terfenadine (H1-receptor antagonist) and inhaled ipratropium bromide (muscarinic receptor antagonist) both increase PC20AMP. OBJECTIVE: To investigate the mechanism of AMP-induced bronchoconstriction in COPD. METHODS: We performed a randomized, double-blind, placebo-controlled, crossover trial. Forty-four nonatopic hyperresponsive smokers with COPD (mean age +/- SD: 60+/-7 years, FEV1 61+/-12% of predicted and FEV1/VC 51+/-8%, geometric mean [GM] PC20methacholine 0.62 mg/mL and GM PC20AMP 6.77 mg/mL) participated. PC20methacholine and PC20AMP were assessed on 3 days. Before the challenges they used either 180 mg of oral terfenadine, 120 microg of inhaled ipratropium bromide, or placebo. RESULTS: GM PC20AMP was 5.44 mg/mL after placebo, increasing with 0.9 doubling concentration (P<0.0001) after terfenadine and decreasing 0.3 doubling concentration after ipratropium bromide (NS). GM PC20methacholine was 0.75 mg/mL after placebo, increasing 0.4 doubling concentration after terfenadine (NS) and 3 doubling concentrations after ipratropium bromide (P<0.0001). CONCLUSION: These findings indicate that histamine release is important in the pathophysiology of AMP-induced bronchoconstriction in smokers with COPD, whereas vagal nerve stimulation does not play a role. Therefore, PC20AMP may be a valuable tool in evaluation of treatments which affect airway histamine release.     

Salbutamol and ipratropium bromide solution in the treatment of bronchospasm in asthmatic children

The effects of the beta 2-adrenergic agonist salbutamol (0.02 mL/kg of a 0.5% solution) and the cholinergic antagonist ipratropium bromide (2 mL of a 0.025% solution), administered alone or in combination at different doses, were evaluated in 48 asthmatic children using a single-dose, double-blind, crossover design. Spirometric measurements were taken before and 10, 30, 60, 120, 180, 240, 300, and 360 minutes after administration of the drugs. All regimens produced significant bronchodilatation 10 to 30 minutes after administration. The improvement began to decline three to four hours after inhalation, particularly when ipratropium bromide was administered alone. The administration of the salbutamol plus ipratropium combination did not significantly improve pulmonary function values as compared to salbutamol alone. The effects of salbutamol and ipratropium bromide in half-dose or full-dose combinations were indistinguishable. No significant adverse effects on blood pressure or heart rate were observed.     

Comparative efficacy of azelastine nasal spray and terfenadine in seasonal and perennial rhinitis

The efficacy and tolerability of intranasal azelastine (0.14 mg/nostril twice daily) and oral terfenadine (60 mg twice daily) were compared under double-blind conditions in two 6-week, multicenter, parallel-group studies, including 167 patients suffering from seasonal and 52 patients suffering from perennial allergic rhinitis. In both studies, patients were symptomatic on entry and showed significant improvement on both treatments within the first 8 d of therapy, showing little further improvement with continued treatment. Symptoms most pronounced on entry – nasal itching, rhinorrhea, sneezing, and nasal obstruction – responded best to treatment (response rates 80–90%). Objective signs such as mucosal swelling and conjunctivitis improved in a manner parallel to symptoms. In perennial rhinitis, azelastine showed a trend to a superior relief of rhinorrhea and nasal obstruction, whereas terfenadine showed a trend toward better control of sneezing and nasal itchiness. No clinically relevant or statistically significant differences between treatments could be identified. The incidence of adverse effects of possible causal relationship to therapy was low. The most frequent effects in azelastine-treated patients were related to application site disorders, e.g., nasal irritation. Results indicate that with the dose used azelastine nasal spray is an effective treatment for both seasonal and perennial allergic rhinitis.     

Additive effect of albuterol and ipratropium bromide in the treatment of bronchospasm in children

Inhaled albuterol (A) (salbutamol) alone and albuterol plus ipratropium bromide (IB) were administered to 12 asthmatic children. Following administration of A alone or in combination with IB, there was a significant increase in FEV1 and FEF. Significant statistical difference in favor of the association A plus IB was observed at 120 and 240 minutes for FEV1 and in the period 120, 180, and 240 minutes for FEF. The additive effect was present both in the large and small airways. The short-lived additive effect of A plus IB suggests the opportunity to increase the frequency of drug administration in patients with severe bronchial obstruction.     

Effects of topical budesonide and levocabastine on nasal symptoms and plasma exudation responses in seasonal allergic rhinitis

This study compares the effects of two topical nasal treatments for allergic rhinitis, budesonide and levocabastine, on symptom development during seasonal pollen exposure. Additionally, the protective effects of drug treatments on allergen-challenge-induced responses (symptoms and microvascular exudation of plasma) are examined late into the pollen season. Forty-four patients with seasonal allergic rhinitis to birch pollen participated in this single-blind, randomized, and placebo-controlled study. Topical nasal treatment with either levocabastine (200 p.g b.i.d.: n = 16), budesonide (200 μg b.i.d.; n = 16), or placebo (n= 12) was instituted before the start of the pollen season and continued for 5 weeks until the end of the birch pollen season. The participants kept diaries for scores of nasal and ocular symptoms. Nasal allergen challenges with increasing doses of a birch pollen extract (10², 10³ and lC SQ-U) were carried out both before, when patients were asymptomatic and without treatment, and late into the pollen season. A nasal lavage followed each challenge, and the lavage fluid levels of albumin were measured as an index of the acute inflammatory response of the allergic mucosa. The birch pollen season was rather mild, producing only small increases in nasal symptoms. Budesonide treatment reduced the total nasal symptoms compared to placebo (P<0.01) and to levocabastine (P<0.05), while levocabastine treatment did not differ significantly from placebo. Ocular symptoms and use of rescue medication did not differ between placebo and the active treatments. At the end of the pollen season, both treatments reduced allergen-challenge-induced nasal symptoms compared to placebo (P<0.01). Only budesonide reduced allergen-challenge- induced increments of albumin levels in postchallenge nasal lavage fluids (P<0.05, in comparison with placebo). The results suggest that budesonide reduces both seasonal and allergen-challenge-induced nasal symptoms, while levocabastine is effective against allergen-challenge-induced symptoms also during the season. In addition, the topical steroid treatment, but not the antihistamine, inhibits the inflammatory exudation evoked by allergen challenge in patients with active seasonal disease.     

Comparison of intranasal cromolyn sodium, 4%, and oral terfenadine for allergic rhinitis: symptoms, nasal cytology, nasal ciliary clearance, and rhinomanometry.

Topical intranasal cromolyn sodium, 4% solution, and oral terfenadine, 60 mg tablets, both relieve symptoms of allergic rhinitis with few or no adverse effects, but no comparison of their relative efficacy has been reported. In this double-blind, double-dummy study, 79 patients, ages 12-56 years with symptoms of allergic rhinitis, were randomized to receive either active cromolyn sodium, 1 spray in each nostril QID, or active terfenadine BID along with the appropriate placebo spray or tablet for 4 weeks following a 1-week baseline qualification period. Patients' daily symptom scores were reviewed weekly and constituted the primary efficacy measures. Changes in nasal cytology, nasal ciliary clearance, and rhinomanometry were also assessed. The presence of adverse effects and the overall score of medication efficacy at the end of each week was recorded. The cromolyn sodium and terfenadine groups had comparable baseline scores for severity of allergic rhinitis symptoms and both treatments resulted in significant improvement (P less than .0001) with no statistical difference between them for total symptom scores at the end of 4 weeks. Eosinophils in nasal samples were decreased significantly in the cromolyn treated group with no significant change in the terfenadine-treated group. There were no significant differences between treatment groups in ciliary clearance or rhinomanometry. Adverse effects were uncommon and mild. We conclude that cromolyn sodium and terfenadine are comparably effective and well-accepted treatments for allergic rhinitis.     

Effect of olopatadine-mometasone combination nasal spray on seasonal allergic rhinitis symptoms in an environmental exposure chamber study

Background

GSP301 nasal spray is a fixed-dose combination of the antihistamine olopatadine hydrochloride and the corticosteroid mometasone furoate intended for seasonal allergic rhinitis (SAR) treatment.

The effect of locally applied ipratropium aerosol on the nasal methacholine challenge in patients with allergic and non-allergic rhinitis

The effect of local pretreatment with ipratropium versus placebo aerosol on nasal methacholine challenge was studied in a double-blind, crossover trial. Fourteen allergic and ten non-allergic patients suffering from rhinitis participated in this study. It can be concluded that intranasal administration of ipratropium has a suppressive effect on hypersecretion and sneezing, but has no influence on nasal airway resistance.     

Quantification of the synergism between fenoterol and ipratropium bromide in the counteraction of experimental bronchospasm

The interaction between the ₂-agonist fenoterol and the antimuscarinic ipratropium bromide in the counteraction of experimental bronchospasm in the guinea-pig was studied qualitatively and quantitatively. Finney's analysis showed a significant overadditive interaction between the two constituents of the association, the overadditivity factor being 2.15 if calculated on the peak activity of 2.68 if calculated on the area under the curve inhibition-time. In addition, the combination possesses both of the advantages of the two components, namely rapid onset of action (characteristic of the -agonist) and long duration of action (characteristic of the antimuscarinic). A study of the principal cardiovascular and hemodynamic parameters in the cat ruled out any synergism between the two drugs at these levels.     

Pulmonary effects of sulfur dioxide exposure and ipratropium bromide pretreatment in adults with nonallergic asthma

In this study we examined the potential short-term effect of sulfur dioxide (SO2) on total respiratory resistance and forced expiratory volume in patients with nonallergic asthma. A group of nine adult subjects with nonallergic asthma, 55 years of age or older, were exposed to SO2 at 0, 0.5, and 1.0 ppm for 20 minutes at rest followed by 10 minutes during light-moderate exercise. The measures of pulmonary function assessed were FEV1, specific total respiratory resistance (SRT), and maximal expiratory flow rates at 50% (Vmax50) and 75% (Vmax75) of expired vital capacity. Measurements were made before exposure to SO2 (baseline), postresting exposure, postexercising exposure, and at 30 minutes thereafter (recovery). Repeat measure analysis of variance revealed a statistically significant dose-response effect of SO2 inhalation on FEV1 (p = 0.008), SRT (p = 0.033), Vmax50 (p = 0.017), and Vmax75 (p = 0.048). Eight subjects had repeat exposure to SO2 at 1.0 ppm after treatment with either placebo or ipratropium bromide, 60 micrograms by metered-dose inhaler. Inpratropium bromide treatment, compared to placebo treatment, resulted in a statistically significant improvement in all baseline measures of pulmonary function: FEV1 (p = 0.017), SRT (p = 0.027), Vmax50 (p = 0.018), and Vmax75 (p = 0.035). However, this drug did not significantly alter the proportionate change in pulmonary function caused by SO2 inhalation in these subjects. These findings indicate that adults with nonallergic asthma are sensitive to short-term low-level SO2 exposure and that treatment with 60 micrograms of ipratropium bromide causes significant bronchodilation but does not protect, completely, these patients from the effect of SO2 inhalation.