This is the 9955th most frequent Russian word.
амфетамина
Amphetamine: A central nervous system stimulant often used medically to treat ADHD and narcolepsy.
Амфетамин is used here as a noun referring to a medical substance.
Амфетамин используется в медицине для лечения некоторых расстройств.
Amphetamine is used in medicine to treat certain disorders.
Амфетамин is here in the instrumental case, амфетамином, denoting the means 'by amphetamine' in the action described.
Некоторые люди злоупотребляют амфетамином, что негативно влияет на их здоровье.
Some people abuse amphetamine, which negatively affects their health.
Амфетамин is used here in the genitive case, амфетамина, specifying the relation to the compound.