Nicotine Replacement Therapy (NRT)

The nicotine replacement therapy (NRT) currently approved by the FDA for use in the United States are nicotine gum, nicotine patch, nicotine nasal spray,  nicotine inhaler, and the nicotine lozenge (Fiore et al., 2000, Schroeder, 2005).

NRTs help tobacco users quit in three ways:

• Nicotine replacement reduces the severity of the withdrawal symptoms.
   
• Nicotine replacement uncouples the behavior changes needed to quit from the unpleasant effects of nicotine withdrawal. This allows the tobacco user to concentrate on learning new behaviors necessary to take the place of tobacco use.
  
  
• These medications partially enhance mood and improve concentration by delivering a smaller quantity of nicotine than delivered by tobacco products.

Withdrawal Management

Pharmacological agents make nicotine withdrawal symptoms manageable for the tobacco user. Some factors need to be considered:

• Amount of nicotine available to suppress symptoms.
  
• Route through which nicotine enters the body.
• Withdrawal symptoms.
  
• Relapse period.

The amount of nicotine available to suppress symptoms. This is usually determined in clinical settings by measuring the person’s cotinine level. Cotinine is a metabolite of nicotine that can be measured with a blood test. Tests of pack-a-day smokers indicate that nicotine replacement products can replace only about half of the amount of nicotine a tobacco user gets by smoking or chewing (Henningfield, Cohen, & Pickworth, 1993; Benowitz, 1988). Underdosing (receiving too little nicotine) is thought to be a major reason for failure in nicotine replacement therapy.

The route through which nicotine enters the body.  When tobacco is smoked, high doses of nicotine enter the blood stream rapidly through the lungs. This high dose (bolus) of nicotine is transported within 10-19 seconds to target areas in the brain (Benowitz, 1999). People, who dip, chew or smoke cigars and pipes adsorb nicotine through the lining of the mouth and often have high cotinine levels (Severson & Hatsukami, 1999; Baker et al., 2000).

Withdrawal symptoms vary in intensity with the individual.  The majority of tobacco users who quit, experience some withdrawal symptoms within hours and symptoms usually peak around 48 hours (Geller, 1996).

The strongest relapse period due to nicotine withdrawal is during the first two weeks (Geller, 1996; Hughes, 1994). Follow up with those quitting tobacco in person, telephone, mail or email is extremely important after the quit date to prevent relapse.
 

Nicotine Replacement Modes of Delivery

All NRTs deliver nicotine to the body differently than cigarettes.  Specifically, the delivery of nicotine is both slower and results in lower nicotine blood levels.  Nicotine replacement is absorbed either through the skin (patches) or through membranes in the nose or mouth (nicotine gum, inhaler,spray, and lozenge).  With this route of administration, nicotine is absorbed slowly and transported to the brain in smaller, even doses. This means that the smoker (or chewer) will not get the same immediate feeling of reward that was a part of smoking. 

Smokers absorb up to 90% of the nicotine in mainstream cigarette smoke (Henningfield, Cohen, & Pickworth, 1993).  Each cigarette yields about 1 mg. of nicotine. The normal adult daily dosage of nicotine is about 20 mg (Henningfield, Cohen, & Pickworth, 1993; Benowitz, 1988). There are 20 cigarettes in a US pack.