I figure that it could be translated as: "expendedor de pastillas/píldoras."

Good morning Dunia, but isn't expendedor more like a vendor?

Thanks for your reply

Dunia,
In this case I think popper is referring to a particular person. I don't think expendedor would be the best fit for this context, but I can't think what would.

In this case "expendedor" is a container that allows you to access easily to the content.

Can be a vendor too.

I have a case that involves a young girl that is a pill popper. If I were to interpret the word pill popper to her parents as espendedor de pildoras. I am more than sure they will think that she is the one dispencing them rather than the one taking them.

and "mancebo"'

I was thinking in an object, so don't take into account my explanation.

I would use consumidora de pastillas.

Thanks, Dunia for your response.

Thanks, Sally.

De nada.

I think mancebo means youth. I am looking for the act of taking pills. I know it is extremely difficult, since it is slang and there is no proper way of saying this.

Thanks.

"Adicta a las pastillas": It implies a dependance on pills

Pastillero

in spanish slang is a person who take pills

So, can I say su hija es una pastillera'