side effect 
noun
A secondary, typically undesirable effect of a drug or medical treatment: many anti-cancer drugs now in use have toxic side effects...
- Most of those who had had a stroke were aware of their own drug treatment and were concerned about the side effect of drugs.
- Tell your doctor if you have had a particular side effect from a pain medication in the past.
- If priapism has occurred as a side effect of medication then a different medication can usually be prescribed.
- inadmissibly
- in advance
- in advance of
- inadvertence
- inadvertency
- inadvertent
- inadvertently
- inadvisability
- inadvisable
- in a fair way to do something
- in a heap
- in a heartbeat
- in a hurry
- in aid of
- inalienability
- inalienable
- inalienably
- in all
- in all but name
- in (all) conscience
- in all honesty
- in all innocence
- in all likelihood
- in all one's born days
- in all one's puff