Question

A 45 year old male with pancreatic cancer is given a prescription for Tarceva (erlotinib). He states that he currently smokes about one pack of cigarettes a day. How should you consult the patient?

1) Smoking increases Tarceva levels and he will experience more side effects if he continues to smoke
2) Smoking decreases Tarceva levels and the medication will be less effective if he continues to smoke
3) Tarceva levels aren't affected by tobacco use
4) Smoking while taking Tarceva is contraindicated

Answer 1

The patient should be informed that smoking decreases the effectiveness of Tarceva (erlotinib) because it increases the breakdown of the drug by liver enzymes, leading to reduced drug levels.

Step-by-step explanation:

The correct answer to the question is: Smoking decreases Tarceva levels and the medication will be less effective if he continues to smoke.

When advising a patient on Tarceva (erlotinib) who smokes, it is important to explain that tobacco smoke can affect the levels of certain medications. Specifically, smoking induces the activity of certain liver enzymes that break down drugs. This induction leads to lower plasma levels of the drugs, meaning that the medication may not reach the therapeutic level needed to be effective against cancer.

As such, it is critical to educate the patient that continuing to smoke while on Tarceva may require adjustments to the medication dosage, and ideally, a plan should be made to assist the patient with smoking cessation to improve the effectiveness of the cancer treatment and their overall health.