nehmen usually means to take something, to take medication, or to choose an option.
In medical contexts it often refers to medication: what should I take, and how often do I take it?
Common Pattern
Common pattern: ich nehme + accusative, e.g. ich nehme die Tabletten zweimal täglich.
How often should I take these tablets?
Wie oft soll ich diese Tabletten nehmen?
Directly useful at the pharmacy.
I have been taking the medication for three days.
Ich nehme das Medikament seit drei Tagen.
Helpful in conversations with a doctor or pharmacist.