Airtec FB 400 Instacap is a combination of two medicines in one inhaler It relieves the long term symptoms of asthma and COPD making breathing easier It works by inhibiting the release of certain chemical messengers that cause inflammation swelling and relaxes the muscles in the airways This medicine is for inhalation purpose only Thus it should not be taken by mouth It is important to follow all the guidelines of doctor before using it However before using it inform doctor if you are suffering from any severe medical condition You should never use this medicine to treat an asthma attack that has already begun as it may cause life threatening condition Tremor insomnia difficulty in sleeping and dry mouth are some side effects of this medicine