15.4 Nicotine Use Disorder Drugs

Nicotine Addiction and Its Effects

Nicotine use disorder is one of the most common substance use disorders you'll encounter in clinical practice. Nicotine creates both physical dependence and psychological habit, which is why quitting is so difficult for patients. Understanding the pharmacology behind nicotine addiction helps you grasp why specific medications work and how to educate patients effectively.

Physiological Effects of Nicotine Addiction

Nicotine binds to nicotinic acetylcholine receptors (nAChRs) in the brain, triggering the release of dopamine. That dopamine surge produces feelings of pleasure and reward, which reinforces the behavior of smoking.

With chronic exposure, the brain upregulates (increases the number of) nAChRs. This leads to tolerance, meaning the person needs more nicotine to get the same effect. When nicotine levels drop, all those extra receptors go unsatisfied, and withdrawal symptoms kick in.

Beyond the brain, nicotine affects multiple body systems:

• Cardiovascular: Increases heart rate and blood pressure; constricts blood vessels, reducing blood flow to the skin and extremities
• Metabolic: Stimulates glucose release from the liver and increases insulin resistance, which can contribute to type 2 diabetes over time
• Appetite/weight: Suppresses appetite and raises metabolic rate, which is why patients often worry about weight gain when quitting
• Immune function: Impairs immune response, increasing risk of respiratory infections and delaying wound healing

Signs of Nicotine Use Disorder

Recognizing nicotine use disorder goes beyond asking "do you smoke?" Look for these clinical indicators:

• Strong, persistent cravings for nicotine
• Difficulty controlling use despite awareness of negative health consequences
• Continued use even when it worsens existing physical or psychological conditions
• Neglecting social, occupational, or recreational activities because of nicotine use
• Developing tolerance (needing more to achieve the same effect)

Withdrawal symptoms appear when a patient tries to quit or cut back. These typically begin within hours of the last cigarette and peak at 2-3 days:

• Irritability, anxiety, and restlessness
• Difficulty concentrating
• Sleep disturbances
• Increased appetite and weight gain

Treatment of Nicotine Dependence

Three main pharmacological options exist for nicotine cessation: nicotine replacement therapies, bupropion, and varenicline. Each works through a different mechanism, and the choice depends on patient history, preferences, and contraindications.

Nicotine Replacement Therapies (NRTs)

NRTs deliver controlled, lower doses of nicotine to the body without the harmful chemicals found in cigarette smoke. Compared to cigarettes, NRTs provide a slower, more stable release of nicotine. This reduces withdrawal symptoms and cravings while allowing the patient to gradually taper off nicotine altogether.

Five forms are available:

Bupropion (Zyban)

Bupropion is an atypical antidepressant that inhibits the reuptake of dopamine and norepinephrine. For smoking cessation, it reduces cravings and withdrawal symptoms through a mechanism that is not fully understood but likely involves its dopaminergic activity. It may also help prevent the weight gain that often accompanies quitting.

• Treatment typically starts 1-2 weeks before the patient's quit date to allow the drug to reach therapeutic levels
• Can be used in combination with NRTs
• Key risks: Dry mouth, insomnia, and a rare but serious risk of seizures. Bupropion is contraindicated in patients with a seizure disorder, eating disorders (bulimia/anorexia), or those currently on MAOIs

Varenicline (Chantix)

Varenicline is a partial agonist at the $\alpha_4\beta_2$ nicotinic acetylcholine receptor subtype. This means it does two things simultaneously:

1. Partial activation of the receptor provides mild dopamine release, which eases cravings and withdrawal
2. Receptor blockade prevents nicotine from fully activating the receptor if the patient smokes, reducing the rewarding effect of cigarettes

Varenicline has shown higher quit rates in clinical trials compared to NRTs or bupropion alone. Treatment begins 1 week before the quit date, with a dose titration schedule over the first week.

• Common side effects: Nausea (most frequent), vivid or abnormal dreams, headache
• Monitoring: Observe for changes in mood or behavior, though the FDA removed its earlier boxed warning about neuropsychiatric events after large-scale studies showed the risk was lower than initially thought
• Contraindication considerations: Use caution in patients with renal impairment (dose adjustment needed) and those with a history of psychiatric illness

Benefits vs. Risks Summary

Comprehensive Approach to Nicotine Addiction Treatment

Medications alone are not enough. Research consistently shows that combining pharmacotherapy with behavioral support produces the best outcomes.

Behavioral Therapy

• Cognitive-behavioral therapy (CBT): Helps patients identify and change thought patterns and behaviors tied to smoking. For example, a patient who always smokes after meals can work on developing a replacement behavior.
• Motivational interviewing: A patient-centered technique that strengthens the patient's own motivation to quit rather than telling them what to do. This is especially useful for patients who are ambivalent about quitting.
• Stress management: Teaches coping techniques like deep breathing, progressive muscle relaxation, and physical activity to handle triggers without reaching for a cigarette.

Relapse Prevention Strategies

Most patients attempt to quit multiple times before succeeding. Relapse is common and should be framed as part of the process, not as failure.

• Help patients identify high-risk situations (social drinking, work stress, being around other smokers) and plan specific coping strategies in advance
• Encourage building a support network of family, friends, and healthcare professionals
• Discuss lifestyle changes that support cessation: regular exercise, avoiding alcohol in early quit stages, keeping hands busy

Nursing Considerations and Patient Education

Nursing Considerations for Cessation Drugs

1. Assess the patient's smoking history, level of dependence (tools like the Fagerström Test for Nicotine Dependence can help), and readiness to quit
2. Educate on proper use, dosing, and side effects of the prescribed medication. For NRTs especially, incorrect use is common (patients often under-dose the gum or remove the patch too early)
3. Monitor for adverse reactions. With bupropion, watch for signs of seizure activity. With varenicline, assess mood and behavior changes at each visit
4. Screen for mental health conditions. Depression and anxiety are more prevalent in smokers, and withdrawal can worsen these conditions. Coordinate with prescribers and behavioral health as needed
5. Encourage a quit date. Patients using bupropion or varenicline should start the medication before their planned quit date (1-2 weeks and 1 week, respectively)
6. Collaborate with physicians, pharmacists, and behavioral therapists to provide comprehensive, team-based care

Patient Education for Smoking Cessation

• Explain the health benefits of quitting with specific timelines: blood pressure and heart rate begin to normalize within 20 minutes, carbon monoxide levels drop to normal within 12 hours, and lung function starts improving within 2-3 months
• Prepare patients for withdrawal symptoms and normalize the experience. Symptoms are temporary and typically peak within the first few days
• Help patients identify personal triggers and develop alternative coping strategies (going for a walk, chewing sugar-free gum, calling a support person)
• Stress the importance of taking medications as prescribed and not stopping early, even if they feel better
• Provide resources: the national quit line (1-800-QUIT-NOW), smokefree.gov, local support groups, and smartphone apps designed for cessation support
• Reinforce that setbacks do not erase progress. Each quit attempt builds skills and increases the likelihood of long-term success
• Celebrate milestones (24 hours, 1 week, 1 month smoke-free) to maintain motivation