is it murder?

She stood next to the kitchen sink.  She reached up to the shelf and grabbed his medicine bottle.
She opened the lid and began pouring the content on to the dry clean towel laying on the counter.  She picked up the first capsule it was yellow and black she carefully opened it and poured its content into the sink.  Then she picked up another and another in continued pouring the content of the capsules into the sink until she had all 30 of them empty.
She picked up the first yellow and black capsules and then she proceeded to fill each one with baking soda.  She continued doing this until she had all 30 of them filled.
She carefully examine each pill to make sure that there was no trace of power on the outside of the capsules.  Then she placed all of the capsules back inside the medicine bottle placed the bottle back on the shelf.
Speaking to herself but saying it out loud "that will teach him to cheat on me".
He had extremely high blood pressure and the medicine is which kept him alive.