When individuals taking certain medicines stop, start or re-start smoking, monitoring and dose changes may be needed.

Using our advice

Some medicines are cleared from the body more quickly in smokers than in non-smokers. This can lead to increased adverse effects on stopping or reduced efficacy if starting (or restarting) smoking. In such individuals, dose adjustments and monitoring may be needed.

Before considering a specific interaction, ensure you are familiar with the following general advice:

Considering drug interactions with smoking

Tobacco smoke can induce liver enzymes, affecting drug metabolism. Some medicines may need dose adjustment or monitoring if a person stops or starts smoking.

Specific recommendations

We provide advice for medicines where a pharmacokinetic interaction with smoking is included in the BNF, Stockley’s Interactions Checker (subscription required) or the manufacturer’s Summary of Product Characteristics. Note that in many cases, the pharmacokinetic interaction is not expected to be clinically significant in practice.