A 50-year-old man has been a

heavy smoker for the last 20 years. 

Smoking can induce specific hepatic enzymes, such as CYP1A2. Verapamil (flow-limited) and phenytoin (capacity-limited) are both eliminated from the body by metabolic degradation catalysed

by some of the induced enzymes. Verapamil has a clearance of 1.5 L/min,

approximately equal to liver blood flow, whereas phenytoin has a clearance of

0.1 L/min.

What will be the effects of

smoking on both verapamil and phenytoin?