Smoking Cessation
Smoking cessation is the most effective intervention in COPD patients as it slows the decline of lung function (FEV1). They should be advised to stop regardless of age and support should be offered with referral to stop smoking services where necessary. It has been estimated that smoking cessation can lead to a sustained 50% reduction in the rate of lung function decline. Any damage already done however, will not be reversed. Smoking has been described as a drug addiction and will require self-motivation to quit. It is important to note that stopping will not have an immediate effect, reduced COPD mortality is not seen until around 10years later. The following graph shows the effect of smoking on lung function:
An up-to-date smoking history, including pack years smoked should be documented for everyone with COPD:
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Calculating pack years = (number of cigarettes smoked X number of years smoked)/20
Unless contraindicated, Nicotine Replacement Therapy (NRT), varenicline or bupropion, should be offered (if appropriate) to COPD patients who plan to stop smoking combined with a support programme where necessary to optimise stop smoking rates. Patients will need follow up support to avoid returning to the habit of smoking. In the early stages symptoms such as coughing may make them start smoking again.
Patients must be prepared mentally to stop smoking, offer advice including:
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Make a list of reasons to stop
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Set a stop date (to have a goal, avoid times of stress if possible)
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Involve family and friends – sometimes easier to stop with someone else
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To avoid relapses – use NRT, avoid places/people who smoke
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Try again if they relapse
What to do?
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Patient wishes to stop immediately– reduce relapse risk by prescribing NRT until two weeks after their stop date.
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High cigarette dependence – consider combining nicotine patch with another form e.g. gum.
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Do not want to quit – Offer NRT to try and reduce smoking amount but explain cutting down is not a substitute for quitting and follow up where needed.
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For further information regarding follow up visit http://cks.nice.org.uk/smoking-cessation#!management
Nicotine Replacement Therapy (NRT)
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Readily available OTC, and is considered safe and effective to stop smoking. Some people benefit from combined therapy.
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Mechanism of action of nicotine: It activates nicotinic acetylcholine receptors in the CNS, which increases neurotransmitter levels and leads to euphoria and relaxation. Withdrawal causes anxiety, craving, depression, irritability, increased appetite and weight gains. NRT prevents withdrawal symptoms by maintaining activation of the receptors.
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Side-effects: Generally safer than smoking. Local irritation can occur and GI upset with oral nicotine. There may also experience problems getting to sleep and abnormal dreams.
Cautions: In haemodynamically unstable patients (e.g. following an MI).
Varenicline (Champix)
A prescription only medicine (although sometimes on a Patient Group Directive [PGD]) that is recommended as an option for smokers who wish to quit. It should be prescribed as part of a support programme. To be started while still smoking and then advise the person to stop smoking 7-14days after starting varenicline. For further dose information visit the following https://cks.nice.org.uk/smoking-cessation#!prescribinginfosub:13
Mechanism of action: A nicotinic receptor partial agonist that reduces withdrawal symptoms and provides the rewarding effects of smoking by binding to the receptors.
Contraindications: Pregnancy and breastfeeding (limited safety information), end-stage renal failure, epilepsy (no clinical experience with this condition).
Cautions: Relapse risk, depression, irritability and insomnia on discontinuation. History of psychiatric illness or cardiovascular disease.
Side-effects: Most commonly nausea. Also taste disturbances, abnormal dreams, appetite changes, dizziness, drowsiness, dry mouth, GI disturbances, headache. Suicidal behaviour – advise to seek help if they experience agitation, depressed mood, or suicidal thoughts.
Interactions: None of clinical significance.
Bupropion (Zyban) – Not used much
An antidepressant that has shown to be successful in smoking cessation. It should be started 1-2 weeks before stop smoking date. For further dose information visit the following https://www.evidence.nhs.uk/formulary/bnf/current/4-central-nervous-system/410-drugs-used-in-substance-dependence/4102-nicotine-dependence/bupropion/bupropion-hydrochloride
Mechanism of action: Inhibits the reuptake of noradrenaline and dopamine in the synaptic cleft, however, the mechanism for smoking cessation benefits is not fully understood.
Contraindications: Severe hepatic cirrhosis, CNS tumour, history of seizures, eating disorders, bipolar disorder and acute alcohol or benzodiazepine withdrawal.
Cautions: Elderly, predisposition to seizures, alcohol abuse, history of head trauma and diabetes. May impair the performance of skilled tasks e.g. driving.
Side-effects: Dry mouth, GI upset, neurological effects such as headache and dizziness, and psychiatric effects such as insomnia, depression and agitation. Hypersensitivity can occur usually presenting as a skin rash.
Interactions: As it is metabolised by cytochrome P450 enzymes its plasma levels are reduced by P450 inducers and increased by P450 inhibitors. Use with monoamine oxidase inhibitors and tricyclic antidepressants increases the risk of adverse effects.
Bibliography:
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RPS supporting patients with COPD
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CPPE – Chronic Obstructive Pulmonary Disease Book 1
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https://www.nice.org.uk/guidance/CG101/chapter/1-Guidance#managing-stable-copd
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Clinical Pharmacy and Therapeutics by Roger and Walker.
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The Top 100 Drugs by A. Hitchings, D. Lonsdale, D. Burrage and E. Baker.
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BNF 72