Asthmatic. Hard breath, wet cough, sneezing. Tried homeo. Prescribed inhaler, L montus. Side effects, safer drug?

My wife is a astmatic patient since 10 years. She will suffer with hard breath, wet cough and sputam willl form heavely. Since 2 years back she used to suffer July to January end quite halfn. We have tried Homeo medicine many years. Since a year she is suffering heavy heard breath, wet cough and sneezes very frequently. Then we consulted Chest Specialist, he has suggested inheller twice a day and L montus daily 2 tablets first two months. Later he has reduced the medicine half the medicine for three months.
Now the problem is if she skips a day taking L montus tablet she immediately elergic systems will appear though it is summer.
My question is does contineous usage of L montus medicine does it have side effects. What side effects will a person will develop. If so which will be the safest drug? Whether she has to use contineously entire life? Please give detailed reply.