Evaluation of an abbreviated adenosine monophosphate bronchial challenge.
BACKGROUND
Airway hyperresponsiveness to adenosine monophosphate (AMP) has been validated as a surrogate marker for airway inflammation. We wished to know whether an abbreviated challenge at the final threshold dose would produce the same fall in FEV1 as a full, conventional dose-response challenge.


METHODS
Seventeen patients with mild-to-moderate asthma (mean FEV1, 75.5% predicted) attended for a full dose-response protocol, where the highest concentration of AMP to produce > 20% fall in FEV1 was noted, along with the maximum percentage fall and recovery time. Patients returned within 2 days for a further challenge, when they received only the highest concentration (as a single bolus) reached on the previous visit.


RESULTS
The mean (+/- SEM) percentage fall in FEV1 after the full challenge was 25.5 +/- 1.3%, and after the abbreviated challenge was 9.4 +/- 2.4%. The mean recovery after the full challenge was 28.13 +/- 4.65 min, and after the abbreviated test was 10.81 +/- 4.27 min.


CONCLUSIONS
An abbreviated challenge using a single bolus dose of AMP grossly underestimates bronchial hyperresponsiveness. Although the pharmacologic half-life of AMP is short (90 s), the lesser response and shortened recovery with the abbreviated challenge suggest a more prolonged physiologic half-life, which in turn may have implications for abbreviated challenge protocols.
Fardon
Tom C
TC
Asthma and Allergy Research Group, University of Dundee, Ninewells Hospital and Medical School, Dundee, DD1 9SY, UK.
Hodge
Melissa R
MR
Lipworth
Brian J
BJ
D000249:Adenosine Monophosphate; D000328:Adult; D001249:Asthma / Q000175:diagnosis / Q000503:physiopathology*; D016535:Bronchial Hyperreactivity / Q000175:diagnosis*; D001985:Bronchial Provocation Tests / Q000379:methods*; D004305:Dose-Response Relationship, Drug; D004334:Drug Administration Schedule; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D008297:Male; D008875:Middle Aged; D012129:Respiratory Function Tests; D015656:Respiratory Mechanics / Q000187:drug effects; D012680:Sensitivity and Specificity; D013997:Time Factors
D000249:Adenosine Monophosphate