The half-life of nicotine is approximately how long?

• A. 0.5 hour
• B. 1 hour
• C. 2 hours
• D. 6 hours

Answer: (C)

Half-life is the time it takes for a drug’s blood concentration to fall by half. For nicotine, the usual value in adults is about two hours, due to the body’s metabolism of nicotine to cotinine and other metabolites, mainly in the liver via enzymes like CYP2A6. Individual factors such as smoking history, liver function, age, and genetics can tweak this a bit, but the typical turnover is around two hours. That’s why nicotine levels drop fairly quickly and why withdrawal symptoms can begin to appear within a few hours after the last exposure. Among the given options, two hours best matches the common pharmacokinetic data for nicotine. A half-life of 30 minutes or 1 hour would imply an even faster drop than usually observed, while six hours would be notably slower than the usual rate. This timing also informs how nicotine replacement therapies are dosed to maintain steady levels and reduce cravings.