Questions & Answers about Мне нужна таблетка от простуды, потому что я чихаю.
Russian often expresses need with a dative construction: мне нужна таблетка literally means (to) me a pill is needed.
- мне = dative of я (to/for me)
- The thing that is needed (таблетка) is the grammatical “subject” in form (nominative), not я.
нужна is the short-form adjective of нужный (needed/necessary) and it agrees with the noun that is needed.
- таблетка is feminine singular → нужна (feminine singular)
Compare: - мне нужен врач (врач = masculine)
- мне нужно лекарство (лекарство = neuter)
- мне нужны таблетки (plural)