Andrographis paniculata leaf extract as a symptomatic intervention for acute respiratory tract infections

Acute respiratory tract infections (ARTIs) which include colds, coughs, and sore throats are common in primary care and there are few viable treatments available. Antibiotics are frequently used to treat ARTIs in primary care, however, these medicines are not suitable as most ARTIs are viral and overreliance on these medicines may lead to antimicrobial resistance (AMR). Herbal medicines have been used for centuries to treat respiratory conditions and a herbal medicine called Andrographis paniculata has previously shown potential in the treatment of ARTIs. This PhD aimed to examine the role that Andrographis paniculata may have in the management of ARTIs and the reduction of AMR.The first phase of this thesis was a systematic review and meta-analysis which included 33 clinical trials and 7175 participants. The results showed that Andrographis was beneficial and safe for relieving ARTI symptoms and reducing time to symptom resolution however the methodological quality of the reviewed trials was limited. The second phase included a qualitative interview study exploring health professionals' attitudes and beliefs around the use of herbal medicines in the symptomatic treatment of ARTIs. There was cautious acceptance of herbal medicines but most participants were concerned about the safety and evidence around herbal medicines. Questions were asked about health professionals'experience around clinical trials of herbal medicines and this information was used to inform the design of a subsequent feasibility study. The third phase of this thesis involved a double-blind randomised placebo-controlled feasibility study evaluating the effect of Andrographis paniculata in the treatment of adults with ARTIs. The results of the feasibility showed that it was possible to recruit and retain participants to a herbal medicine and that Andrographis paniculata may have potential to reduce the number of antibiotics prescribed.My findings indicate that Andrographis paniculata may be a useful herbal medicine in the treatment of ARTIs although more research is required. Data from the feasibility study can be used in the design and implementation of a larger full-scale trial. This PhD thesis adds new knowledge on the use of Andrographis paniculata as a potentially useful herbal medicine for the treatment of ARTIs. Firstly, it includes a comprehensive systematic review on Andrographis paniculata which identified articles from both English and Chinese language databases. Secondly, It is the first qualitative study within UK primary care that has examined health care providers' views on herbal medicines for ARTIs. Finally, the data from the double-blind randomised controlled feasibility study in the UK on Andrographis paniculata can be used to guide the design and implementation of future larger full-scale trials