| Methods |
Double blind randomised controlled crossover trial. |
| Participants |
304 patients (aged 14‐72 years) recruited of whom, underwent tartrazine (n = 277), aspirin, sodium salicylate and acetaminophen challenges. Selection criteria were that they had reversible obstructive airways disease (ATS criteria) and a positive bronchial challenge response to histamine and/or methacholine. Many were on oral corticosteroids. |
| Interventions |
After taking a detailed history about previous history of intolerance to foods containing tartrazine, subjects with no history of intolerance were given 50 mg tartrazine. Those with a positive history were given different doses ( 1, 5, 15, 25, 50 mg) in a double‐blind manner randomised with placebo (200mg lactose) on separate days. Challenges were monitored with half‐hourly lung function tests. All bronchodilators and anti‐histamines (but not corticosteroids) were withheld for 6 to 12 hours prior to the challenge. |
| Outcomes |
FEV1 (litres). 20% fall in FEV1 defined a positive test result. |
| Notes |
This study was primarily investigating aspirin intolerance and 74 patients were exclude from aspirin challenge tests because of recorded severe reactions to the drug. |
| Risk of bias |
| Bias |
Authors' judgement |
Support for judgement |
| Allocation concealment (selection bias) |
Unclear risk |
Information not available |
