This is the 13496th most frequent Russian word.
нарколога
A narcologist (doctor specializing in addiction treatment).
Here, 'нарколога' is in the genitive case, used possessively to mean 'this narcologist's'.
Я доверяю мнению этого нарколога.
I trust this narcologist's opinion.
The word 'нарколога' is used in the genitive case to indicate 'to a narcologist'.
Мне дали направление к нарколога на консультацию.
I was referred to a narcologist for a consultation.
The word 'нарколога' appears in the accusative case as the object of the action 'called'.