The hypothesis of this study is that the onset of rapid bronchodilatory effect of inhaled Formoterol (12 microgram) is comparable to that of inhaled salbutamol (200 microgram) i.e., the difference in mean forced expiratory volume in 1 second (FEV1) between the 2 groups at 1, 5, 10, 30 and 60 minutes will be less than 10% in children between 5-15 years with mild acute exacerbation of asthma.

It is desirable to have a single MDI that can be used as both LABA and SABA. There are few studies involving few children on use of formoterol that shows rapid bronchodilatation in children with asthma and no study that used it as rescue drug in children with acute exacerbation of asthma. The purpose of the present study is to evaluate whether the rapid bronchodilatory effect of formoterol is similar to that of salbutamol in children of 5-15 years with mild exacerbation of asthma.

Children will receive either salbutamol or formoterol by MDI. Participants will be explained about the study, spirometry and inhalation of medicine with MDI and spacer. Children will receive two puffs (100 microgram each of salbutamol) or Formoterol 2 puffs (6µg /puff) by MDI and spacer. Each child will be explained about the inhalation technique by using a MDI of placebo. After shaking the MDI it will be attached to spacer (700ml volume) and actuated. Child will be asked to take 5 tidal breaths. Another puff will be given by similar method.

Inclusion Criteria:

1. Children aged 5-15 years of either sex seeking treatment with mild exacerbation of asthma in pediatric chest clinic or Pediatric OPD

2. Mild exacerbation will be defined as:

   • children presenting with increase in symptoms (cough, wheeze, breathlessness) for less than 7 days duration
   • no chest indrawing
   • no difficulty in speech
   • clinical asthma score (or pulmonary index score-annexure 1) between 6-9

Exclusion Criteria:

1. Children with life threatening asthma detected by presence of any of the following:

   • severe chest indrawing
   • cyanosis
   • irregular respiration
   • altered sensorium

2. Children with other chronic respiratory conditions like tuberculosis, cystic fibrosis or other acute illness that would complicate current treatment and response for asthma

3. If child has taken salbutamol in last 6 hours or if he is on long acting beta agonists (formoterol or salmeterol)

4. Child not able to perform spirometry

5. Parents refusing to give consent