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Clinician’s Corner: Prescription drugs for smoking cessation

Last week we discussed the role of nicotine replacement products. This week we will focus on the role of prescription drugs indicated for smoking cessation.

The effect of smoking on drug metabolism:

Hydrocarbons found in tobacco smoke induce CYP450 microsomal enzymes. Smoking cessation or the use of nicotine products may alter the clearance of many drugs including: Smoking causes a “speed-up” of the metabolism of these drugs. When a patient quits smoking, levels of these drugs will probably increase:

  • theophylline, acetaminophen, caffeine, clozapine, oxazepam, olanzapine, phenothiazines, propranolol, imipramine, insulin, cimetidine, ergot alkaloids, and alpha blockers.

Bupropion (Zyban150®)

Usual dose 150mg daily for 3 days. Then increase to 150mg twice daily. Separate doses by 8 hours.

Initiate treatment when patient is still smoking. Takes 1 week to achieve steady state blood levels.

Set a target quit date within the first 2 weeks of treatment. Continue treatment for 7 to 12 weeks.

After 7 weeks of treatment failure, unlikely patient will succeed. Stop dose. May be combined with nicotine patches. Blocks re-uptake of dopamine and norepinephrine. Weak nicotinic receptor antagonist. Consider for smokers with history of depression. This drug is safe for patients with cardiovascular disease. This drug may be useful in delaying weight gain from smoking cessation.

AVOID: if bipolar, pregnant or history of seizures.

Varenicline (Chantix®)

Mechanism: nicotinic receptor partial agonist. Having the drug on board blocks some of the pleasurable effects that patients get if they smoke. Have patients set quit day around day 8, after fully titrated.

STARTER PACK: Dose: day 1-3: 0.5mg daily

  • Day 4-7: 0.5mg BID
  • Day 8-through end of treatment- 1mg BID
  • Assess after 12 weeks. If successful start a second 12-week drug course.

Common Adverse effects: Nausea, dream changes, constipation, gas and vomiting.

Prescribe with caution:

  • Chantix should NOT be used by pilots, air traffic controllers, truckers, and bus drivers.
  • Reports have become prevalent about psychiatric symptoms and suicides in patients using Chantix. (Due to Chantix or nicotine withdrawal???) This has recently prompted the FDA to implement a black box warning.
  • Suggested link to heart attacks, seizures, diabetes, dizziness, and confusion
  • Report changes in mood or behavior.
  • Caution driving until patient sees how the drug affects them.

Patient education:

  • Set a quit date. Start Chantix® one week before that. Prescribe the “starter pack.”
  • Take after a meal with a full glass of water.
  • Caution if kidney problems, pregnant (Category-C) or nursing

Second Line Drugs for Smoking Cessation:

  • Nortriptyline (Pamelor): Blocks reuptake of norepinephrine with a lesser effect on serotonin. Similar efficacy to bupropion or nicotine replacement, but safety profile limits its usage.
  • Clonidine (Catapres): Stimulates alpha-2-adrenoceptors in the brainstem and reduces sympathetic outflow

Pharmacist Role: Dr. Boris Lushniak (former Acting Surgeon General) at a Salus University commencement address stated that ALL health care professionals should discuss at EVERY encounter diet, exercise and smoking cessation. No matter if you are a physical therapist, optometrist or pharmacist we need to offer our skills to these patients! Although we have focused on these healthy changes for the New Year, we need to engage our patients throughout the year…

Have a great day on the bench!

Pete Kreckel   Thompson Pharmacy Broad Avenue