N-isobutyrylcysteine, a donor of systemic thiols, does not reduce the exacerbation rate in chronic bronchitis.

A. Ekberg-Jansson, M. Larson*, W. MacNee, A. Tunek, L. Wahlgren, E.F.M. Wouters

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

Abstract

N-isobutyrylcysteine, a donor of systemic thiols, does not reduce the exacerbation rate in chronic bronchitis.

Ekberg-Jansson A, Larson M, MacNee W, Tunek A, Wahlgren L, Wouters EF, Larsson S.

Lung Division, Sahlgrenska University Hospital, Goteborg, Sweden.

N-isobutyrylcysteine (NIC), a new thiol compound that is not rapidly hydrolysed to give higher levels of free thiols in the body than N-acetylcysteine (NAC), was used to test if the effect of NAC on exacerbations in chronic bronchitis was an effect of the unhydrolysed thiol compound. Smokers or exsmokers with chronic bronchitis forced expiratory volume in one second (FEV1) >40% and reversibility < or = 10% predicted were treated with oral NIC 300 mg b.i.d. or placebo for 24 weeks. Steroids, NAC, antibiotics, and nonsteroid anti-inflammatory drugs use were restricted. Exacerbations were recorded by a respiratory symptom diary card and the time to onset of the first exacerbation after the start of treatment was measured using life-table analysis. Spirometry was performed at each visit. Six hundred and thirty-seven patients were randomized to treatment with NIC (n=316) or placebo (n=321). NIC did not prolong the time to first exacerbation (life-table analysis, p=0.59) and no increase in FEV1 or forced vital capacity was observed. Altered taste perception, taste loss and anosmia occurred more often in the NIC group (p<0.001). In conclusion, N-isobutyrylcysteine, a N-acetylcysteine-like drug with a greater bioavailability has, contrary to N-acetylcysteine, no effect on exacerbations in chronic bronchitis. This suggests that the effect of N-acetylcysteine on exacerbations in chronic bronchitis is not due to the relatively low free thiol levels (other than glutathione) produced by N-acetylcysteine therapy.

Publication Types:
Clinical Trial
Multicenter Study
Randomized Controlled Trial
Original languageEnglish
Pages (from-to)829-834
Number of pages6
JournalEuropean Respiratory Journal
Volume13
Issue number4
DOIs
Publication statusPublished - 1 Jan 1999

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