Efficacy of Chaihu Jisang decoction on post-infection cough and its effect on cough reflex sensitivity

To investigate the efficacy of Chaihu Ji Sang Decoction (CJSD), (a modification of Xiao Chaihu Tang (Minor Decoction of Bupleurum) was evaluated in patients with post-infection cough (PIC). Its effect on cough reflex sensitivity (CRS) was also described.

One hundred and eighteen patients with PIC were enrolled and randomly divided into an experimental group and control group (54 patients in each group). The experimental group was given CJSD orally, and the control group was given cetirizine hydrochloride for 7 d. Cough symptom scores and TCM symptom scores were compared before and after treatment. Efficacy, cough onset time, recurrence, and adverse drug reactions were additionally evaluated. Finally, CRS was evaluated before and after treatment of PIC patients in the experimental group.

Fifty-two patients in the experimental group and fifty control patients completed the study. Cough symptom scores and the TCM symptom scores of the two groups were significantly improved after treatment, however cough symptoms in the experimental group 1 (0, 2) were significantly lower than the control group 2 (1, 2) after treatment (P < 0.05). Similarly, TCM symptom scores 4 (0, 7) in the experimental group were significantly lower than the control group 6 (3, 12) (P < 0.01). Overall, the effective rate of the experimental treatment (84.60%) was significantly higher than that of the control treatment (68.00%) (P < 0.01). The onset time of efficacy of the experimental treatment was one day faster than the control treatment [2 (2,3) d vs 3 (2,3) d, P < 0.01]. The relapse rate in the experimental group (9.09%) was lower than that of the control group (29.41%) (P < 0.05). 39 PIC patients in the experimental group completed a capsaicin cough challenge test before treatment. The lgC2 and lgC5 of the experimental group prior to treatment was 1.19 (0.59, 1.49) and 1.80 (1.49, 2.10), respectively. The lgC2, lgC5 of the healthy control group was 1.49 (0.89, 2.40) and 2.70 (2.40, 3.00), respectively. The differences in lgC2 and lgC5 between experimental group and healthy groups were significant at this time point (both P < 0.01). After treatment, 34 patients in the experimental group received re-examination. lgC5 increased from 1.80 (1.49, 2.10) to 2.10 (1.49, 3.00). CRS after treatment/re-examination was significantly lower than those of baseline in the experimental group (P < 0.05).

CJSD could effectively improve the clinical symptoms of PIC patients, with demonstrable low recurrence and safety. CJSD also significantly decreased the CRS in patients with PIC.