NRT delivers much lower doses of nicotine than smoking. But caution is advised in patients with a history of angina, recent myocardial infarction or cerebrovascular accident, cardiac arrhythmias, hypertension or peripheral vascular disease.

Because of the effects of nicotine on metabolism, caution is also advised in diabetes,
hyperthyroidism and phaeochromocytoma. Possible side effects include hiccups, sore throat, headache, nausea and dizziness, but these are unlikely. Nicotine withdrawal symptoms are also possible.

The only interaction that is possibly directly attributable to NRT is with adenosine.