Safety of nicotine in smokers with hypertension

Cigarette smoking remains the major preventable cause of premature cardiovascular disease. The risks of cigarette smoking are particularly high in people with hypertension. Cigarette smoking acts synergistically with hypertension and hyperlipidemia to increase the risks of acute myocardial infarction and sudden death.1 In hypertensive patients, cigarette smoking also accelerates the development of renal disease and increases the likelihood of progression to malignant hypertension.2,3 Clearly, it is of utmost importance that smokers with hypertension quit smoking. Physician counseling to quit smoking is helpful, but quit rates remain quite low. Provision of medication to aid cessation doubles the quit rate compared to counseling alone, and is recommended by the U.S. Agency for Healthcare Research and Quality Guidelines for all smokers, unless specifically contraindicated.4 The available medications to aid smoking cessation include nicotine products (transdermal nicotine, nicotine gum, nicotine nasal spray, nicotine inhaler, and nicotine lozenges) and bupropion. Nicotine products have been used for many years, and there is evidence that transdermal nicotine is safe in patients with a history of cardiovascular disease.5,6 However, little research has been done on the safety of nicotine therapy in patients with hypertension in particular. The major cardiovascular toxicity of cigarette smoking is probably mediated by the effects of oxidant gases and carbon monoxide.5 The possible contribution of nicotine to adverse cardiovascular events has been a concern, both among physicians and patients. Nicotine acts as a sympathomimetic drug, resulting in catecholamine release, acutely increasing heart rate and blood pressure (BP) and constricting coronary arteries. Nicotine has also been reported to have adverse effects on endothelial function and may impair insulin tolerance, although the biologic relevance of these effects in individuals remains unclear.7,8 Although nicotine acutely increases BP and heart rate, the effects of regular daily cigarette smoking on BP are not clear. In studies with casual office BP measurement, BP tends to be lower in cigarette smokers compared to nonsmokers.9–11 Studies of ambulatory BP recording have revealed variable results, with studies showing higher, lower, or no difference in ambulatory BP in smokers compared to nonsmokers, or in smokers when they are smoking compared to when not smoking.12–16 Naturally, there is concern that nicotine medications used by smokers might adversely effect BP. The study by Tanus-Santos and co-workers17 is a useful first step in assessing the risks of nicotine therapy in hypertensive patients. They found that transdermal nicotine applied for 4 h increased BP and heart rate in hypertensive nonsmokers, but had no significant effect in smokers. The difference in response is probably due to the presence of tolerance to effects of nicotine in smokers. Tolerance develops to many of the cardiovascular effects of nicotine, including its pressor effect.18 The study has limitations in that the nicotine patch was placed for only 4 h, whereas patches are normally used for 16 to 24 h per day. The study also involved a small number of subjects and the hypertensive subjects were only mildly hypertensive and were treated with hydrochlorothiazide. However, the results are reassuring and support the idea that clinical trials can be safely conducted using nicotine therapy for longer periods of time in smokers with even more severe hypertension. In summary, cigarette smoking is extremely injurious to the cardiovascular system of smokers. Cigarette smoking delivers nicotine as well as combustion products, carbon monoxide, and other cardiovascular toxins. Nicotine replacement therapy is clearly less hazardous than cigarette smoking, even in patients with cardiovascular disease. Transdermal nicotine, in particular, has been shown to be safe in cardiovascular disease patients in general, and appears to have no adverse short-term effect on BP in smokers with mild hypertension. Current research strongly supports that pharmacotherapy should be offered to all smokers, even those with hypertension or other cardiovascular disease, to optimize the likelihood that they will quit smoking.