Final answer:
Cigarette smoking does not increase tricyclic antidepressant concentrations, while certain medications and substances can.
Step-by-step explanation:
The correct answer is D. Cigarette smoking does not increase tricyclic antidepressant concentrations.
Cigarette smoking does not affect the metabolism of tricyclic antidepressants, therefore, it does not increase their concentrations in the body. Other factors, such as concurrent use of certain medications or substances, can influence the levels of tricyclic antidepressants in the body.
For example, medications like clozapine, haloperidol, risperidone, and methylphenidate can increase tricyclic antidepressant concentrations. These substances may inhibit the enzymes responsible for metabolizing tricyclic antidepressants, leading to higher concentrations in the body.