During smoking, the nicotine from the cigarette causes receptors in the brain to release several chemicals, including dopamine, which cause many of the positive feelings. During quitting smoking, the lower levels of these chemicals cause miserable signs and symptoms of nicotine withdrawal. Signs and symptoms like irritability, insomnia and difficulty concentrating begin four to six hours after the last cigarette and can last for month or more after stopping smoking.

Varenicline (Chantix)

Varenicline stimulates the release of low levels of dopamine and other chemicals in the brain to help reduce the signs and symptoms of withdrawal. In addition, Chantix blocks nicotine receptors in brain. So if you lapse and have a cigarette, the cigarette doesn't stimulate the brain's receptors the way it did in the past. Cigarettes become much less pleasurable, and the desire to return to regular smoking again may be reduced

This is the latest medication approved by the FDA for smoking cessation. The brand name is Chantix. It blocks some of the rewarding effects of nicotine (the addictive drug in tobacco products) and at the same time it tackles the withdrawal symptoms that the most people feel after they quit. It is used with care in patients who are using antipsychiatry medications. These medications are to be taken for 12 weeks; some individuals may need treatment for more than 12 weeks. The side effects of this medication are nausea, headache, vomiting, sleeplessness, and abnormal dreams. It is not to be taken in pregnant women and in women who are breast feeding.

Bupropion (Zyban or Wellbutrin)

It is designed to help reduce cravings for nicotine. It can also relieve symptoms of depression for some patients. It should not be used if you have history of seizures or eating disorders or are currently using a monoamine oxidase (MAO) inhibitor or any other form of Bupropion (such as Zyban or Wellbutrin). Treatment is recommended for seven to 12 weeks. The common side effects are dry mouth, difficulty in sleeping.

Nicotine Replacement Therapies (NRT)

Nicotine patches:  They are small, self adhesive patches. Patches are designed to provide a steady and continuous stream of nicotine through the skin over a designated time (16-24 hours, depending on the product). The patch is available via prescription or over the counter (OTC). It is designed to give enough nicotine to ease cravings. Treatment is typically recommended for six to eight weeks. The trade names are Nicoderm CQ, Habitrol.

Nicotine chewing gum:  It is recommended for smokers who want something to turn to when experiencing urges to smoke. Chew up to 20-30 pieces a day for six to eight weeks. Use the 4 mg gum if you’re smoking 25 cigarettes or more per day or using chewing tobacco. Use the 2 mg gum if you’re smoking less than 24 cigarettes a day. The brand names are Nicorette and Thrive. It can cause gum, tooth or jaw soreness. It is given for 12 weeks period.

Nicotine Inhaler: Patients "puff" small doses of nicotine through this prescription product which looks similar to a cigarette. Unlike a cigarette, there is no harmful carbon monoxide. Treatment usually lasts eight to 12 weeks, depending on the patient.

Nicotine nasal spray: This prescription product sprays nicotine into your nose. Recommended use is up to two sprays an hour for as many as three months. The trade name in Nicotrol.

Lozenge: This medication is usually used eight to 12 weeks. It is available as 2mg, 4mg dose. Patients are urged to use at least 6 to 12 lozenges per day. It can cause nausea, heart burn or hiccups. Up to 20 lozenges can be used per day. The brand name is Commit. It should be places between the gum and cheek.

Nicotine inhalers: It is a device which allows low doses of nicotine to be delivered. The brand name is Nicotrol. It may sometime cause coughing, mouth or throat irritation. It is used for 6 to 12 weeks. It should not be used in patient with asthma or other lung disorder