Pharmaceutical care to patients in a smoking cessation group at a Brazilian teaching hospital

The mechanisms for drug interactions with smoking and clinically significant pharmacokinetic and pharmacodynamic drug interactions with smoking are reviewed. Polycyclic aromatic hydrocarbons (PAHs) are some of the major lung carcinogens found in tobacco smoke. PAHs are potent inducers of the hepatic cytochrome P-450 (CYP) isoenzymes 1A1, 1A2, and, possibly, 2E1. After a person quits smoking, an important consideration is how quickly the induction of CYP1A2 dissipates. The primary pharmacokinetic interactions with smoking occur with drugs that are CYP1A2 substrates, such as caffeine, clozapine, fluvoxamine, olanzapine, tacrine, and theophylline. Inhaled insulin's pharmacokinetic profile is significantly affected, peaking faster and reaching higher concentrations in smokers compared with nonsmokers, achieving significantly faster onset and higher insulin levels. The primary pharmacodynamic drug interactions with smoking are hormonal contraceptives and inhaled corticosteroids. The most clinically significant interaction occurs with combined hormonal contraceptives. The use of hormonal contraceptives of any kind in women who are 35 years or older and smoke 15 or more cigarettes daily is considered contraindicated because of the increased risk of serious cardiovascular adverse effects. The efficacy of inhaled corticosteroids may be reduced in patients with asthma who smoke. Numerous drug interactions exist with smoking. Therefore, smokers taking a medication that interacts with smoking may require higher dosages than nonsmokers. Conversely, upon smoking cessation, smokers may require a reduction in the dosage of an interacting medication.

OBJETIVO: Avaliar o perfil dos pacientes e fatores associados ao sucesso do tratamento do fumante. MÉTODOS: Estudo retrospectivo dos pacientes que foram atendidos no ambulatório de apoio ao tabagista do Hospital de Messejana, no Ceará, durante o período de outubro de 2002 a abril de 2005. O tratamento foi avaliado considerando-se o perfil do tabagista, tipo de medicação e período de utilização da mesma. RESULTADOS: Do total de 320 pacientes atendidos, 65,6% eram mulheres. A média de idade do início do tratamento foi de 48 anos, sendo 33 anos o tempo médio de uso do tabaco. Acima de 90% deles iniciaram o tabagismo antes dos vinte anos de idade. Daqueles que se encontravam no programa havia pelo menos um ano (258 pessoas), 50,8% atingiram o sucesso terapêutico, 17,8% recaíram e 31,4% não pararam de fumar. Sucesso parcial foi atingido, em média, na quinta semana do tratamento e a recaída foi predominante no quarto mês. Cerca de 60% dos pacientes utilizaram terapia medicamentosa. CONCLUSÃO: A chance de parar de fumar foi associada significativamente ao uso de medicação, independentemente do perfil tabágico avaliado. No segundo ano do programa, observou-se maior associação da bupropiona à terapia de reposição nicotínica, com conseqüente elevação da taxa de sucesso e tendência à redução da recaída.

Tobacco use is the leading cause of preventable death and disability in the world. Although gradually declining in most developed countries, the prevalence of tobacco use has increased among developing countries. Treatment for tobacco use and dependence is effective, although long-term abstinence rates remain disappointingly low. In response, new treatments continue to be developed. In addition, many of the pharmacotherapies that have been available for years have found new applications with the use of medication combinations, higher doses and a longer duration of therapy for approved medications. There are now seven medications (nicotine patch, nicotine gum, nicotine lozenge, nicotine inhaler, nicotine nasal spray, bupropion sustained release and varenicline) approved for tobacco dependence treatment in most countries, and many national and professional society practice guidelines recommend their use. Although each of the medications used for tobacco dependence treatment has been rigorously tested for efficacy and safety, broader experience in clinical trials and in observational population-based studies suggests that adverse events associated with these medications are relatively common. Since 2008, two of the medications (varenicline and bupropion) have come under increasing scrutiny because of reports of unexplained serious adverse events (SAEs), including behaviour change, depression, self-injurious thoughts and suicidal behaviour. To date, this association has not been shown to be caused by these medications, but concerns about medication safety continue. Prescribers require a working knowledge of the common adverse effects for all of these medications as well as a more detailed knowledge of the SAE potential. Nicotine replacement therapy (NRT) has been rigorously tested in clinical trials for over 30 years. A number of adverse effects are commonly associated with NRT use, although SAEs are rare. The adverse effects associated with NRT are due to the pharmacological action of nicotine as well as the mode and site of the NRT application. Bupropion has been tested in over 40 controlled clinical trials and has been associated with higher rates of treatment discontinuation due to adverse events than NRTs. A number of SAEs are associated with bupropion and new warnings were recently added to bupropion prescribing information because of observed neuropsychiatric symptoms including suicidal thoughts and behaviours. Varenicline is the most recently approved medication for tobacco dependence treatment and, although proven safe in clinical testing, new safety concerns have arisen based on post-marketing reports. Warnings have been added to the prescribing information for varenicline because of neuropsychiatric symptoms also including suicidal thoughts and behaviours. Informed decision making regarding the use of pharmacotherapy for the treatment of tobacco dependence requires knowledge about the risks of drug treatment that is weighed against the risks of continued tobacco use and the benefits of treatment. Over half of all long-term smokers will die of a tobacco-related disease and the risk of a serious or life-threatening adverse event with tobacco cessation pharmacotherapy is vanishingly small. Pharmacotherapy for tobacco dependence is also among the most cost-effective preventive health interventions. Given these factors, the benefit : risk ratio is strongly in favour of pharmacotherapy for tobacco dependence treatment in virtually all smokers who are motivated to quit.