Cuando cierto farmaco se toma oralmente, su concentracion en el torrente sanguineo del paciente

Power going out story i need with a plot and the starting point is you wake up late, the power is out, and yeah. plz try to make it non complex since i have to write it in spanish if you want to go all out it needs to be in the preterit tense also know as past

If you wanted to say something in spanish, what would you say?

(i put) la carta dentro de uno de estos.