As many as 70% of smokers want to quit, some half-heartedly, others committedly. However, nearly half of those who commit fervently in the beginning ultimately end up succumbing to nicotine cravings. Several factors elicit strong cravings in both current as well as newly-abstaining smokers, such as social gatherings, peer pressure and the sight of other people smoking. Whatever the reason, almost all smokers find themselves on the merry-go-round of quitting and starting several times. Consequently, anti-smoking pharmacotherapy procedures are necessary.
Quitting smoking is a struggle, a real one at that. This is because nicotine has an addictive potential and brings about a lot of pathophysiological changes in your body, one of which is the development of tolerance. When you smoke for a long time, the nicotine receptors in your body adapt and saturate, requiring an increased dose of nicotine to produce the same sensation they first did. This is called nicotine dependence. This dependence and tolerance makes you crave more cigarettes. On the other hand, abruptly quitting smoking sparks withdrawal symptoms. This explains why most smokers, after having quit several times, keep coming back.
Nicotine dependence warrants medical intervention — called pharmacotherapy — for smoking cessation.
Pharmacotherapies for smoking cessation block the effects of nicotine and reduce withdrawal symptoms. These are generally safe and effective for both short and long-term use, and include:
Nicotine-Replacement Therapy (NRT) — the first-line therapy for smoking cessation recommended by the United States Public Health Service (2008) and the US Preventive Services Task Force (2015).
The NRT contains one-third to one-half the amount of nicotine found in most cigarettes, keeping the nicotine in the body at a sufficient enough level to curb cravings and withdrawal effects.
When you inhale cigarette smoke, nicotine is quickly absorbed from your lungs into your body where it binds with nicotine receptors to produce the desired effect. The NRTs, on the other hand, are designed to release nicotine slowly in the body, prolonging its effects and mitigating cravings. The dosage of NRTs is then tapered gradually and ultimately stopped.
There is convincing evidence that the use of NRT substantially increases success rates among non-pregnant smokers, i.e., in one study, the rates of abstinence increased from 10% (in the control placebo group) to 17% in people who used NRTs.
The NRTs include:
· Nicotine gum and lozenges – release nicotine slowly in the mouth.
· Nicotine transdermal patch – sticks to your skin where it releases nicotine for a long period of time.
· Nasal spray and inhaler – contains a holder and a puff which when pressed, releases vapors of nicotine into your mouth.
As for the side-effects of NRTs, you may experience a bad taste in the mouth, an upset stomach, heartburn, cough and skin rash.
Bupropion — Bupropion is an anti-depressant that has a use in smoking cessation therapies. It prevents nicotine withdrawal by blocking reuptake of the neurotransmitters dopamine and noradrenaline.
The U.S. Food and Drug Administration (FDA) has approved bupropion as a first-line treatment for tobacco cessation. While it is effective in smokers with or without a history of depression, it has been reported to work better among smokers with a history of depression. The depressive people currently on Bupropion express a self-desire to quit smoking. However, this drug could be a better choice for smokers with a history of depression.
Bupropion treatment is targeted, i.e., it begins when the patient is still smoking and a target date of quitting smoking is set within 2 weeks of the onset of therapy.
Bupropion increases the risk of seizure and should be avoided in individuals with a history of epilepsy or seizure disorder, and head trauma etc.
Nortriptyline — is a tricyclic anti-depressant medication that has been found effective in smoking cessation in several clinical trials. It a second-line medication for tobacco cessation.
Clonidine — Clonidine, originally approved for hypertension, is an alfa-2-adrenergic receptor agonist that decreases central sympathetic activity. Through its action on the central nervous system, it is said to decrease withdrawal symptoms associated with smoking cessation. However, its use in smoking cessation is limited due to its adverse effects such as sedation, dizziness and dry mouth. Clonidine should not be stopped abruptly as it can lead to a hypertensive crisis. It is recommended as a second-line treatment for smoking cessation.
Anxiolytics — Nicotine withdrawal can precipitate symptoms of anxiety, stress and mood swings in smokers. Anxiolytics such as alprazolam, can be used for symptomatic treatment in such individuals. However, anxiolytics are not used directly to facilitate smoking cessation.
Varenicline — is a non-nicotine medicine beneficial in smoking cessation. Varenicline is a partial agonist at the alfa4-beta2 receptor in the central nervous system where it prevents the binding of nicotine and produces a response lesser than that of nicotine (30-60%). It maintains a moderate level of dopamine in the brain thereby reducing craving and withdrawal effects.
Varenicline is typically begun 1-2 weeks before the quitting date. The dose is gradually increased to prevent the risk of relapse. It provides a long-term benefit. Its adverse effects include nausea, vomiting, headache, flatulence, insomnia and mild nightmares.
Nicotine Blockade Therapy — Blockade therapy is given to mitigate or eliminate rewarding pharmacological effects of smoking, should the person revert to the drug use.
- Mecamylamine – is used in combination with counseling to reduce craving for smoking and helps as many as 50% of the smokers to give up smoking within 2 weeks of initiation of treatment.
- Naltrexone – It is a long acting opioid antagonist that treats nicotine dependence in the same way as opioid dependence.