We now understand more about the addictive nature of nicotine -- the powerful drug in cigarettes and cigars that reaches the brain within seconds of inhaling. (Smoking, which some scientists believe is harder to quit than heroin or cocaine addiction, is so addictive that even after a heart attack, only half of patients who smoke manage to quit.)

      Today, there are better products to help the 47 million smoking Americans attempt to quit. The latest to garner headlines is bupropion (Zyban), the first non-nicotine medication to join an ever-growing field of nicotine replacement products such as gums, patches, nasal sprays and inhalers.

      While there's no guarantee of success, statistics indicate that many of these products -- typically used for 6 to 12 weeks -- can double your chances of success compared to trying to quit cold turkey, from about 5% cold turkey to 10% with these products. Your chances of success improve even more, to between 20 and 40%, if you also join a "stop smoking" program that offers individual or group therapy in conjunction with using these products.

Zyban (Bupropion Hydrochloride)

      The best news to come out of smoking cessation research is the drug Zyban, a prescription antidepressant that has been commercially available for several years (under the trade name Wellbutrin). Zyban, in tablet form, is the first smoking cessation product that works without delivering nicotine to satisfy the body's desire for it. However, studies show that its effectiveness may be even stronger when it is used along with nicotine replacements.

      Advantages: It's easy to use and is nicotine-free, so you can avoid increased heart rate and other symptoms associated with nicotine intake. We are not exactly sure why it works, but Zyban is effective for many smokers -- both those who do and don't have a tendency toward depressed moods. One theory is that the drug affects certain chemicals in the brain that are related to nicotine addiction, and may mimic actions similar to those of nicotine by releasing dopamine and other brain chemicals. Zyban also seems to reduce the urge to smoke, and decreases the amount of weight gain during quitting.

      Disadvantages: The main side effect is a potential to cause seizures, so anyone with a head injury or epilepsy shouldn't take the drug. Also, people with anorexia or bulimia shouldn't take Zyban because, for reasons that are not known, they are more likely to experience seizures when taking the drug. Minor side effects that may occur include dry mouth, difficulty sleeping and skin rash.

Nicotine Patches

      These products cut the cravings of withdrawal by delivering a steady stream of nicotine through the skin and into the blood, where it is delivered to the brain. Nicoderm CQ and Nicotrol are now available without a prescription, while a prescription is needed for three others -- ProStep, Habitrol and generic patch. All patches work the same way, by delivering nicotine and suppressing withdrawal symptoms.

      Advantages: Nicotine patches have few significant side effects and seem to offer the best results. Patches are also easy to use; you simply apply once daily to a relatively hairless part of the body, such as the upper arm.

      Disadvantages: Minor skin rashes are common where the patch is placed, and nicotine is delivered slowly to the brain.

Nicotine Gums

      Nicotine is absorbed through the lining of the mouth; the amount delivered to the brain is determined by how many pieces of gum are chewed throughout the day. Now available without a prescription, gums such as Nicorette show good results. Alone, they are not as effective as patches, but the success rate is equal when used in conjunction with a "stop smoking" program.

      Advantages: Easy to obtain and available in multiple dosages (2 mg. and 4 mg.).

      Disadvantages: Bad-tasting to some and a proper chewing technique must be learned. You have to chew slowly to release nicotine, then hold the gum in the mouth to give the drug time to be absorbed. If you chew too quickly and swallow your saliva, the nicotine isn't absorbed. Also, you can't eat or drink anything while using the gum, and people with dental problems may find it difficult to use the gum.

Nicotine Sprays

      Available by prescription, nicotine nasal sprays are used the same way you'd use a decongestant spray for allergies -- a quick spurt up the nostrils. Products such as Nicotrol NS produce blood nicotine levels most similar to those produced by smoking, since you get a quick jolt of nicotine, as opposed to the steady level provided by the patch.

      Advantages: May be the best choice for heavy smokers because it will more closely mimic the nicotine delivery they are used to.

      Disadvantages: Not as convenient as the patch or gum, since you may be in situations where it would be impossible or inappropriate to use the spray. These products are too new to adequately judge their long-term effectiveness, but in the short term, they are at least as effective as nicotine gums and patches.

Nicotine Inhalers

      The newest nicotine replacers on the market, Nicotrol inhalers are nicotine cartridges that are inserted into a plastic tube shaped like a cigarette. The smoker puffs the nicotine through the tube, where it is absorbed through the lining of the mouth.

      Advantages: These prescription products are about as effective as nicotine patches or gum and may appeal to people who miss the physical hand-to-mouth action of smoking.

      Disadvantages: Inhalers need to be used frequently -- about 80 to 100 puffs equal the nicotine amount typically derived from one piece of nicotine gum. Inhalers can also cause irritation of the mouth and throat.

What to Expect

      Whatever you and your doctor choose, expect most withdrawal symptoms to subside after the first week or so, and be completely gone within about a month, with the most dramatic decline in the first week or two. The only symptom that persists longer than a month is the craving. And that's where nicotine replacement products can be useful for longer periods of time -- to quell the cravings.

      For very heavy smokers, doctors will sometimes recommend a combination of products -- for example, using a patch for a steady flow of nicotine, along with a nasal spray to deliver periodic "hits." The goal is to eventually wean off both. However, never combine nicotine replacement products on your own without first consulting a doctor.

      Most people eventually wean themselves off the replacements. About 20% of people who successfully quit will continue with long-term use of the replacements -- sometimes for years. But eventually, they, too, gradually cut down on their usage.

      I recommend that people use replacements for as long as necessary to stay off cigarettes. Other than some cardiovascular-stimulating effects, nicotine has no known side effects. And considering the cardiovascular and carcinogenic properties of tobacco, the nicotine replacements are definitely preferred.