Nedocromil sodium 2% eye drops for twice-daily treatment of seasonal allergic conjunctivitis: a Swedish multicentre placebo-controlled study in children allergic to birch pollen

A contemporary look at allergic conjunctivitis

Allergic eye disease is common, yet often overlooked in North America. In the U.S., up to 40% of the population is deemed to be affected and this number is growing. Symptoms and signs of ocular allergy can lead to decreased productivity and negatively impact quality of life (QoL). Various treatment options exist to achieve symptom control. For allergic conjunctivitis, ophthalmic agents include antihistamines, mast cell stabilizers, dual-activity agents, nonsteroidal anti-inflammatory drugs (NSAIDs), steroids and some off-label treatments. Immunotherapy is recommended as a therapeutic option. This review provides a summary of the forms of ocular allergies, with a focus on symptoms and signs, impact on QoL, physical examination, diagnosis and therapeutic options of allergic conjunctivitis. Through multidisciplinary collaborations, a simplified algorithm for the treatment of allergic conjunctivitis is proposed for Canadian clinical practice.

Topical antihistamines and mast cell stabilisers for treating seasonal and perennial allergic conjunctivitis

BACKGROUND

Seasonal/perennial allergic conjunctivitis is the most common allergic conjunctivitis, usually with acute manifestations when a person is exposed to allergens and with typical signs and symptoms including itching, redness, and tearing. The clinical signs and symptoms of allergic conjunctivitis are mediated by the release of histamine by mast cells. Histamine antagonists (also called antihistamines) inhibit the action of histamine by blocking histamine H1 receptors, antagonising the vasoconstrictor, and to a lesser extent, the vasodilator effects of histamine. Mast cell stabilisers inhibit degranulation and consequently the release of histamine by interrupting the normal chain of intracellular signals. Topical treatments include eye drops with antihistamines, mast cell stabilisers, non-steroidal anti-inflammatory drugs, combinations of the previous treatments, and corticosteroids. Standard treatment is based on topical antihistamines alone or topical mast cell stabilisers alone or a combination of treatments. There is clinical uncertainty about the relative efficacy and safety of topical treatment.

OBJECTIVES

The objective of this review was to assess the effects of topical antihistamines and mast cell stabilisers, alone or in combination, for use in treating seasonal and perennial allergic conjunctivitis.

SEARCH METHODS

We searched CENTRAL (which contains the Cochrane Eyes and Vision Trials Register) (2014, Issue 7), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE (January 1946 to July 2014), EMBASE (January 1980 to July 2014), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com), ClinicalTrials.gov (www.clinicaltrials.gov) and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 17 July 2014. We also searched the reference lists of review articles and relevant trial reports for details of further relevant publications.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) comparing topical antihistamine and mast cell stabilisers, alone or in combination, with placebo, no treatment or to any other antihistamine or mast cell stabiliser, or both, that examined people with seasonal or perennial allergic conjunctivitis, or both. The primary outcome was any participant-reported evaluation (by questionnaire) of severity of four main ocular symptoms: itching, irritation, watering eye (tearing), and photophobia (dislike of light), both separately and, if possible, by an overall symptom score. We considered any follow-up time between one week and one year.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data and assessed risk of bias. Disagreements were resolved by discussion among review authors and the involvement of a third review author. We followed standard methodological approaches used by Cochrane.

MAIN RESULTS

We identified 30 trials with a total of 4344 participants randomised, with 17 different drugs or treatment comparisons. The following antihistamines and mast cell stabilisers were evaluated in at least one RCT: nedocromil sodium or sodium cromoglycate, olopatadine, ketotifen, azelastine, emedastine, levocabastine (or levocabastine), mequitazine, bepotastine besilate, combination of antazoline and tetryzoline, combination of levocabastine and pemirolast potassium. The most common comparison was azelastine versus placebo (nine studies).We observed a large variability in reporting outcomes. The quality of the studies and reporting was variable, but overall the risk of bias was low. Trials evaluated only short-term effects, with a range of treatment of one to eight weeks. Meta-analysis was only possible in one comparison (olopatadine versus ketotifen). There was some evidence to support that topical antihistamines and mast cell stabilisers reduce symptoms and signs of seasonal allergic conjunctivitis when compared with placebo. There were no reported serious adverse events related to the use of topical antihistamine and mast cell stabilisers treatment.

AUTHORS' CONCLUSIONS

It seems that all reported topical antihistamines and mast cell stabilisers reduce symptoms and signs of seasonal allergic conjunctivitis when compared with placebo in the short term. However, there is no long-term data on their efficacy. Direct comparisons of different antihistamines and mast cell stabilisers need to be interpreted with caution. Overall, topical antihistamines and mast cell stabilisers appear to be safe and well tolerated. We observed a large variability in outcomes reported. Poor quality of reporting challenged the synthesis of evidence.

Pain and placebo in pediatrics: a comprehensive review of laboratory and clinical findings

Pain modulation by placebo mechanisms is one of the most robust and best-studied phenomena, yet almost all research investigating the mechanisms and implications of the placebo analgesia are based on adult research. After highlighting crucial aspects that need to be considered in studying pain modulation in children, this comprehensive review examines studies related to pain modulation with an emphasis on factors such as age, neural development and pain measures. We critically discuss psychological mechanisms underlying placebo effects, including (1) verbally induced expectations, (2) conditioning and learning mechanisms, and (3) child-parent-physician interactions. Taken together, research suggests that placebo mechanisms can affect therapeutic outcomes and potentially be exploited clinically to improve clinical outcomes in pediatric population. Recommendations for further investigating the mechanistic bases and harnessing placebo effects for supportive therapeutic applications are given.

Comparative study of the ocular efficacy and safety of diclofenac sodium (0.1%) ophthalmic solution with that of ketorolac tromethamine (0.5%) ophthalmic solution in patients with acute seasonal allergic conjunctivitis

Background:

Seasonal allergic conjunctivitis (SAC) is the most common and most prevalent of allergic disorders which afflict the ocular surface. Of the several treatments available, ophthalmic non-steroidal anti-inflammatory drugs, are generally very safe and tolerable.

Aim:

The aim of this study is to compare the ocular efficacy and safety of diclofenac sodium (0.1%) ophthalmic solution with that of ketorolac tromethamine (0.5%) ophthalmic solution in patients with acute SAC.

Materials and Methods:

Sixty patients with signs and symptoms of SAC were evaluated in an open, randomized, parallel group study. The principle symptoms (ocular itching, burning, discharge, photophobia) and signs (ocular inflammation, lid edema, chemosis, conjunctival mucous, keratitis) were evaluated.

Study Design:

Patients were randomized into two groups of 30 each. Patients in group A received one drop of diclofenac sodium 0.1% and patients in group B received ketorolac tromethamine 0.5% in both the eyes four times a day for fourteen days. Evaluations were performed at day 0, 3, 7 and 14 of the therapy. At each visit, the signs and symptoms were rated using a scale from 0-3 (mild-1, moderate-2 and severe-3).

Results:

Significant clinical and statistical reductions in signs and symptoms from baseline were observed in both groups. Diclofenac sodium 0.1% was superior to ketorolac tromethamine 0.5% in reducing ocular itching (P < 0.05) and ocular inflammation (P < 0.05), at the final examination.

Conclusion:

Diclofenac sodium showed statistically significant better results at day 3 and 7 compared to ketorolac.

Double-masked, randomized, parallel-group study comparing olopatadine 0.1% ophthalmic solution with cromolyn sodium 2% and levocabastine 0.05% ophthalmic preparations in children with seasonal allergic conjunctivitis

BACKGROUND

It is estimated that >50% of medications have not been tested in children. Physicians need pediatric data to guide them in treating children. Olopatadine hydrochloride ophthalmic solution 0.1% is a topical antiallergic agent that is both an antihistamine with high affinity and selectivity for the histamine H1 receptor and a mast cell stabilizer that inhibits the release of histamine and other proinflammatory mediators from human conjunctival mast cells. The efficacy and tolerability of olopatadine has been demonstrated by comparative studies in adults and children with seasonal allergic conjunctivitis (SAC).

OBJECTIVE

Pediatric patient data were extracted from 2 clinical trials to assess the efficacy and tolerability of olopatadine hydrochloride ophthalmic solution 0.1% compared with those of cromolyn sodium ophthalmic solution 2% and levocabastine ophthalmic solution 0.05% as treatment for SAC in children.

METHODS

In study 1, conducted at 15 centers in 7 countries (Europe and Australia) from October 1995 to December 1997, olopatadine was instilled BID and placebo (vehicle) BID for 6 weeks and compared with cromolyn instilled QID. Study 2, conducted at 17 centers in 8 countries (Europe and Australia) from November 1998 to June 2000, compared olopatadine BID with levocabastine BID. In both studies, children of either sex and any race, aged 4 to 11 years, and having proven grass pollen allergies were assigned to treatment in a double-masked, randomized fashion. Slit-lamp examination, the physician's impression scale, and self-ratings were used to obtain efficacy data. Data analyses were based on pollen concentrations. The tolerability assessments were based on visual acuity, pupil diameter, intraocular pressure, and a dilated fundus examination.

RESULTS

Study 1 comprised 30 children (olopatadine [n = 13] and cromolyn sodium [n = 17]; 18 boys, 12 girls; mean age, 7.9 years [range, 4-11 years]). Study 2 comprised 22 children (olopatadine [n = 10] and levocabastine [n = 12]; 12 boys, 10 girls; mean age, 8.6 years [range, 5-11 years]). In study 1, ocular itching (P = 0.010), redness seen on slit-lamp examination (P = 0.003), and eyelid swelling (P = 0.034) were significantly less intense with olopatadine than with cromolyn sodium during the peak pollen period. In study 2, redness seen on slit-lamp examination (P = 0.040) and self-rated ocular redness (P = 0.024) were significantly less intense with olopatadine than levocabastine during the peak pollen period. Olopatadine was well tolerated.

CONCLUSION

Olopatadine hydrochloride ophthalmic solution 0.1% was more effective than both cromolyn sodium 2% and levocabastine 0.05% ophthalmic preparations in controlling ocular signs and symptoms of SAC in children and was well tolerated when administered twice daily for 6 weeks.

Supplementation of fexofenadine therapy with nedocromil sodium 2% ophthalmic solution to treat ocular symptoms of seasonal allergic conjunctivitis

PURPOSE

Ocular symptoms are often under-treated in patients with allergic rhinoconjunctivitis. The efficacy of fexofenadine hydrochloride 60 mg capsules supplemented with nedocromil sodium 2% ophthalmic solution was evaluated to determine the optimal drug regimen for control of ocular allergic symptoms.

METHODS

In this 5-week, open-label, randomized, multicentre comparative study, 89 patients with documented ragweed pollen allergy received fexofenadine b.i.d. with nedocromil rescue, fexofenadine q.d. with nedocromil b.i.d., or fexofenadine rescue with nedocromil b.i.d. during the ragweed pollen season.

RESULTS

For all regimens, mean symptom severity scores for itching, burning, tearing, redness, grittiness, discharge, light sensitivity and swelling improved significantly (P < 0.003). Similarly, all groups experienced significant (P < 0.02) improvement in all clinical signs: erythema, oedema, discharge, conjunctival injection and conjunctivitis, as well as quality-of-life scores (P < 0.0001). All regimens reduced overall symptom severity scores after 5 min (P < 0.05) with relief persisting over 12 h (P < 0.03). Improvements in mean symptoms, signs and quality-of-life scores were similar among the treatment groups as were onset and duration of action even though patients in two of the three study arms were taking one-half or less of the recommended fexofenadine dosage. Patients and physicians judged the regimens containing lower fexofenadine dosages (with nedocromil b.i.d.) to be more effective overall than the regimen containing the highest fexo-fenadine dosage (with nedocromil as rescue only).

CONCLUSIONS

Supplementation of oral fexofenadine therapy with nedocromil sodium 2% ophthalmic solution relieves ocular symptoms of seasonal allergic rhinoconjunctivitis, allowing control of rhinal symptoms with half the recommended dosage of fexofenadine.

Nedocromil sodium ophthalmic solution 2% twice daily in patients with allergic conjunctivitis

In a multicenter, open-label evaluation, 1098 patients with ocular itching and a history of perennial or seasonal allergic conjunctivitis instilled one drop of nedocromil sodium 2% twice daily in each eye. Ocular symptoms, signs, and global improvement were assessed at baseline and 1 month; satisfaction scores, quality-of-life variables, and adverse events were also recorded. Significant improvements from baseline (P<.012) occurred in mean severity scores for itching, burning, stinging, watering, swelling, tired eyes, dryness, gritty sensation, eye pain, foreign-body sensation, and light sensitivity. Physicians reported significant reductions (P<.0001) in bulbar conjunctival redness and swelling. Two thirds of patients (634/954) and three fourths of physicians (710/954) reported at least 75% improvement in overall condition after 1 month. The most common adverse events were burning (2.7%) and unpleasant taste (1.4%); headache (1.2%) and adverse events leading to discontinuation (1.3%) were rare. Patients reported significant improvement (P<.001) in their ability to perform daily activities; 65% were more satisfied with nedocromil than with their typical medication. Physicians would prescribe nedocromil again to 80% of the patients. Nedocromil sodium 2% twice daily was effective and safe for the treatment of symptoms of allergic conjunctivitis, significantly improving quality of life and producing high rates of user and physician satisfaction.

Twice-daily and once-daily nedocromil sodium 2% ophthalmic solution for the treatment of seasonal allergic conjunctivitis

In this 8-week open-label, prospective study, 30 patients with grass pollen allergy and ocular itching instilled nedocromil sodium 2% ophthalmic solution twice daily for a 5-day baseline period, followed by once-daily dosing thereafter. Physicians assessed clinical signs after the twice-daily period and after weeks 1 and 3 of the once-daily period; patients rated ocular symptoms daily. Use of specified rescue medication was permitted. Symptom scores for ocular itching, stinging, redness, swelling, burning, tearing, and light sensitivity did not differ significantly between the dosage periods. Scores for erythema, edema, conjunctival injection, and the entire conjunctiva decreased slightly during once-daily administration; discharge scores were unchanged. Of the 20 patients who used rescue medication, only 5 increased their usage by more than two doses per week during the once-daily period. Eighty-three percent of patients were willing to continue the once-daily regimen during the next allergy season. Physicians rated overall control of seasonal allergic conjunctivitis with once-daily administration as "good" or "moderate" in 100% of the patients; 93% of patients applied those ratings themselves. Nedocromil sodium 2% ophthalmic solution instilled once daily maintains control of symptoms in patients who are established on a twice-daily regimen.

Nedocromil sodium in golfers with seasonal allergic conjunctivitis

To evaluate nedocromil sodium 2% ophthalmic solution for the treatment of seasonal allergic conjunctivitis, 24 golfers with documented ragweed-pollen allergy instilled eyedrops twice daily for 4 days prior to golf-course intervention and 15 minutes before playing a round of golf during peak ragweed season. Ocular symptoms were scored at baseline (7 days before golfing), prior to instillation on the day of golf, and 30 minutes, and 1, 4, 8, and 12 hours after tee-off. Physician assessment was performed prior to tee-off, before tee-off on the ninth hole, and at the end of the 18th hole. Itching, burning, grittiness, tearing, redness, and light sensitivity were significantly decreased after nedocromil administration, as were erythema, edema, conjunctival hyperemia, and overall findings in the conjunctiva. Symptom severity scores fell approximately 30 minutes after instillation, with improvements persisting 8 and 12 hours after treatment. Most patients (92%) rated the treatment moderately or completely effective, and 83% were willing to continue its use. Physician assessments of effectiveness agreed with those of the patients. In this open-label study, nedocromil sodium eyedrops relieved the ocular symptoms of seasonal allergic conjunctivitis for up to 12 hours, well beyond a usual round of golf.

Efficacy and acceptability of nedocromil sodium 2% and olopatadine hydrochloride 0.1% in perennial allergic conjunctivitis

In this 2-week, randomized, crossover study, ophthalmic solutions of nedocromil sodium 2% and olopatadine hydrochloride 0.1% were compared for effectiveness and acceptability in 28 patients with perennial allergic conjunctivitis and previous olopatadine experience. Patients received nedocromil twice daily or olopatadine twice daily for 1 week, then were crossed over to the alternate medication for 1 week. Outcome measures were patient satisfaction (questionnaire), severity of ocular symptoms (daily diary scores), clinical signs (physician assessments), quality of life (questionnaire), and global assessments of effectiveness. Both medications were well accepted. Of the 28 patients, 16 (57.1%) would request a nedocromil prescription, 10 (35.7%) an olopatadine prescription (P = .157); 22 patients (78.6%) would recommend nedocromil to other allergy sufferers, while 18 (64.3%) would recommend olopatadine (P = .480). Light sensitivity scores were significantly lower with nedocromil (P = .0125); other symptom scores were comparable between medications. Both drugs significantly (P < .01) and comparably decreased erythema, conjunctival injection, and overall conjunctival signs from baseline. Comparable improvement also occurred in quality-of-life scores. Both physicians and patients judged nedocromil and olopatadine to be similarly effective in preventing signs and symptoms. Nedocromil sodium 2% is an effective treatment for perennial allergic conjunctivitis. Patients receiving olopatadine can be switched to nedocromil with no loss in efficacy or satisfaction, but with a reduction in cost.

Comparison of topical nedocromil sodium and oral terfenadine for the treatment of seasonal allergic conjunctivitis

This double-masked, comparative, multicenter study was conducted to assess the onset of action and tolerability of nedocromil sodium 2% ophthalmic solution BID, 60-mg terfenadine tablets BID, and placebo in the treatment of seasonal allergic conjunctivitis. Two hundred sixty-eight patients in whom seasonal allergic conjunctivitis was diagnosed were assigned to 1 of 3 groups and administered study medication for 4 weeks. Patients' mean age was 33 years (range, 12 to 68 years); 57.8% (155 of 268) were female. Demographic characteristics were similar in all 3 groups. Although all 3 groups showed improvement in ocular symptoms, nedocromil sodium was associated with a statistically significantly faster onset of action than was terfenadine or placebo (P = 0.038). During the study, 29 nedocromil sodium-treated patients (36.7%) achieved control of symptoms in < or =2 minutes, and 61 (77.2%) achieved control in < or =15 minutes. The corresponding numbers were 21 (24.7%) and 50 (58.8%) in the terfenadine group and 25 (29.1%) and 48 (55.8%) in the placebo group. The frequency of adverse events was low and similar between groups (nedocromil sodium, 26; terfenadine, 32; placebo, 32). No severe treatment-related adverse events were reported. In conclusion, nedocromil sodium had a significantly faster onset of action than did terfenadine or placebo.

Nedocromil sodium eye drops are more effective than sodium cromoglycate eye drops for the long-term management of vernal keratoconjunctivitis

BACKGROUND

Vernal keratoconjunctivitis (VKC) is a severe though transient form of ocular allergy, predominant in young males, which requires careful management. Corticosteroids are effective but also cause serious topical side-effects in the eye, such as glaucoma and cataracts. The safer, mast cell stabilizing anti-inflammatories (commonly sodium cromoglycate) therefore have an important role. This parallel group study compared efficacy, tolerability and safety of sodium cromoglycate 2% with nedocromil sodium 2%, administered as one drop per eye four times daily for a period of 5 months.

METHODS

Children aged 4-17 years, with a diagnosis of mostly limbal VKC in the last 12 months, entered a 2-week baseline during which they used only artificial tears, and were then randomized to treatment, in groups of 18, on an investigator single-masked basis. Daily symptom diary cards were kept by patients/guardians, and VKC was assessed by the clinician at approximately monthly intervals. Dexamethasone was provided for rescue control of severe symptoms, if needed.

RESULTS

A total of 34 patients completed the study. Both trial treatments produced rapid improvements and many ocular signs and symptoms, including Trantas' dots, chemosis, itching, soreness and sticky discharge, were fully controlled by the end of the study. However, nedocromil sodium took effect more quickly, with a significant reduction compared to sodium cromoglycate for itching, grittiness, hyperaemia and keratitis within 6 weeks. In addition, nedocromil sodium was the more efficacious overall (significant vs sodium cromoglycate for hyperaemia, keratitis, papillae and pannus at 22 weeks). Both treatments were well tolerated and without serious adverse effects. Final opinions favoured nedocromil sodium, with full control of VKC recorded for 94% (patient opinion) and 100% (clinician opinion) of this treatment group, compared with 29% and 0%, respectively, in the sodium cromoglycate group.

CONCLUSIONS

Nedocromil sodium 2% eye drops is significantly more effective than sodium cromoglycate for treatment of VKC.

Ocular medications in children

Many ocular medications are used by pediatricians or ophthalmologists caring for pediatric patients. Topical antibiotics are commonly prescribed for bacterial conjunctivitis, nasolacrimal duct obstructions, and ophthalmia neonatorum. Many new antiallergy eye drops are now available for the treatment of seasonal (hay fever) conjunctivitis. Dilating eye drops and antiglaucoma medications are generally used or prescribed by ophthalmologists, but pediatricians must be aware of their potentially serious systemic side effects. Before initiating treatment, physicians should evaluate the risks and benefits of ophthalmic medications, establish minimum dosages necessary to achieve a therapeutic benefit, and monitor children for local and systemic side effects.

A multicenter comparison of the ocular efficacy and safety of diclofenac 0.1% solution with that of ketorolac 0.5% solution in patients with acute seasonal allergic conjunctivitis

Only one of several available ophthalmic nonsteroidal anti-inflammatory drugs (NSAIDs) is currently FDA approved for use in acute seasonal allergic conjunctivitis (SAC). Sixty patients with SAC and moderate itching and bulbar conjunctival injection were enrolled in a multicenter, randomized, double-masked, parallel-group trial comparing diclofenac sodium (DS) with ketorolac tromethamine (KT). Patients instilled 1 drop four times daily while awake for 14 days. Ocular signs and symptoms were evaluated at one and two weeks. The primary efficacy variables were itching and bulbar conjunctival injection. For both treatments, the ocular allergy sign and symptom scores were comparable at baseline. Both treatments evaluated in this study were well tolerated. Significant clinical and statistical reductions from baseline were observed in the primary efficacy variables. Treatment group differences were observed for the pain/soreness score with an advantage observed for the DS group at 30 minutes and at day 7. Our conclusion is that diclofenac sodium and ketorolac tromethamine acted similarly to reduce the ocular signs and symptoms associated with acute seasonal allergic conjunctivitis. There was a statistically significant advantage for the DS group to be free of symptoms at the day 7 visit as compared to the KT group (20.7% vs. 3.2%).

Comparative therapeutic studies with Tilavist

Comparative clinical trials which include known therapies as well as placebos are essential in constructing a solid basis from which to 'launch' any new drug. This applies especially to eye drops for treatment of seasonal allergic conjunctivitis, where the symptomatology, already dependent on the vagaries of the natural pollen challenge season, is further influenced by a positive washing action of the placebo eye drops. Tilavist (2% nedocromil sodium ophthalmic solution) has therefore been compared with sodium cromoglycate eye drops and non-sedating antihistamine tablets, both mainstays in the treatment of seasonal allergy, in a series of double-masked, placebo-controlled, mainly multicentre studies. Nedocromil sodium, twice or four times daily, proved as effective overall as sodium cromoglycate (2% or 4% four times daily) in three seasonal trials, and was the more effective treatment in a study of patients with vernal keratoconjunctivitis. Its efficacy was most evident during peak periods of pollen challenge, when neither placebo nor sodium cromoglycate eye drops controlled breakthrough symptoms. Three further seasonal studies showed nedocromil sodium eye drops to be as effective as standard oral doses of astemizole and terfenadine, whilst a faster onset of action than terfenadine was reported in one multicentre study.

Clinical experience with Tilavist: an overview of efficacy and safety

A programme of clinical studies was carried out to determine the basic efficacy and safety of 2% nedocromil sodium eye drops (Tilavist) in treating allergic conjunctivitis, in 2,905 patients from 3-76 years of age. Results of all the double-masked placebo comparative studies completed to date-five in vernal keratoconjunctivitis (VKC), five in perennial (PAC) and 16 in seasonal allergic conjunctivitis (SAC)-have been assessed in a statistical overview analysis. Nedocromil sodium, administered four times daily to 153 patients with VKC, was significantly more effective than placebo (155 patients) and in the clinicians' opinion gave good control in 76% of cases, compared with 46% for placebo (p < 0.001). Patients with chronic symptoms of PAC also responded better to nedocromil sodium given four times daily (n = 146) rather than twice daily (n = 86), and significantly more patients (p < 0.001) were effectively controlled by four times daily treatment with nedocromil sodium (72%) than with placebo (47%; n = 156). Twice-daily dosage with nedocromil sodium (n = 677) was adequate for SAC, however, and the treatment was statistically better than placebo (p < 0.01-p < 0.001) whether dosed twice or four times daily. Speed of action was assessed in seven SAC studies in which 79% of all patients (n = 295) using nedocromil sodium had experienced relief of symptoms when questioned, half of them within 15 minutes and 74% during the first hour after dosing. Test treatments were well-accepted by both adults and children, and there were no major adverse events. Minor irritations reported more frequently with nedocromil sodium than placebo were stinging or burning of the eyes on application of the drops and a distinctive taste, noted by 5% of the active treatment group (n = 1,552).