As the fore-runner, nicotine replacement therapy is the longest-standing of the existing pharmacological smoking cessation interventions currently available. It aims to alleviate nicotine withdrawal symptoms by substituting the nicotine attained through tobacco smoking via alternative means (e.g. nasal sprays, inhalers, gum and tablets, transdermal patches). The various nicotine replacement therapy products available have differing durations of action and allow patients to tailor their nicotine intake according to their particular needs.For example, patches can be used to substitute for background nicotine and gums or tablets can be used to help satisfy urges.