Individuals are not at equal risk of tobacco dependence.
G enetic component: smoking behaviour; the initiation/ maintenance of smoking, the number of cigarettes smoked& the response to pharmacologic treatments.
A strong link exists between tobacco use & psychiatric disorders *2- 3, as schizophrenia, depression, drug addiction, suggests shared neurobiologic / behavioural abnormalities.
Tobacco may be used to improve the psychiatric condition or to reduce the side effects of some psychiatric medications,as tobacco smoke contains chemical substances other than nicotine that inhibit monoamine oxidase A/B in the brain mimic the effects of antidepressants, may explain the increased risk of depression for 6 months or longer following smoking cessation.
Reduces nicotine withdrawal symptoms&the desire to smoke.
Several products;patch, gum, nasal spray, inhaler, tablet , lozenge.
No difference demonstrated between products.
Ineffectiveness is often due to improper use or insufficient dosage.
The dosage should be adjusted if there are clinical signs of toxic effects( nausea insomnia, palpitations) or of insufficient dosage (i.e. severe withdrawal symptoms as irritability, restlessness, anxiety, increased appetite, depressed mood).
If a patient finds one type ineffective or intolerable, it is useful to try another.
A nicotinic receptor partial agonist, acting like an agonist or an antagonist depending on the state of activation of nicotinic receptors.
Through its intrinsic partial activation of the α4β2-nicotinic acetylcholine recs, elicits a moderate/ sustained increase in mesolimbic dopamine& counteract the low dopamine encountered in the absence of nicotine during smoking cessation attempts.
By competitively binding to α4β2-nicotinic acetylcholine receps, as a partial agonist, protects against nicotine-induced dopaminergic activation if the patient smokes&disrupt the reinforcing effects of nicotine& compensate for withdrawal symptoms.
A significant effect on smoking cessation rates, higher than bupropion ,but no direct comparison with NRT conducted.
Varenicline efficacious in preventing smoking relapse.
Started at 0.5 mg once daily for the first 3 days, 0.5 mg twice daily for the next 4 days then 1 mg twice daily, for a total duration of 12-24 weeks (lower dosage in kidney disease or dialysis).
The main side effect of varenicline therapy is nausea ,30%.