Prescribing Review - Drugs used in Asthma and COPD


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Drugs used in Asthma and COPD

There are approximately 5.2 million people with asthma in the UK today, one in ten children suffer from asthma.¹ Data from the Quality and Outcomes Framework (QOF) show that 3.1 million people are listed on asthma registers (5.8% of patients registered with practices in England)², this appears to underestimate asthma prevalence. Across English PCTs the percentage score for the asthma domain of the QOF ranged from 74.8% to 99.2% of the total points available (median 92.8%).² Chronic obstructive pulmonary disease (COPD) mainly affects middle aged and elderly people. According to the QOF data almost 717,000 people are listed on COPD registers.² Across English PCTs the percentage score for the COPD domain ranged from 61.8% to 98.8% of the total points available (median 88.5%).² Prescribing of drugs to treat asthma and COPD (chart 1) has increased very slowly over the last 5 years with higher prescribing occurring in the quarter to December each year. Spending on these drugs has risen by 37% over the last 5 years and this is mainly due to increased prescribing of Seretide® and Symbicort® (chart 2).

Asthma

The British Thoracic Society and Scottish Intercollegiate Guidelines Network guideline on management of asthma has been updated to include new evidence.³ Three stepped pathways (adults, children aged 5-12 years and children under 5 years) are used to manage treatment for achieving and maintaining control of asthma symptoms. All steroid doses in the pathways refer to beclometasone delivered via a metered dose inhaler (MDI).

At Step 1 an inhaled short-acting ß2 agonist is used as required (this is at least as good as regular use four times daily) for all patients with mild intermittent asthma.³ At Step 2 inhaled steroids can be introduced in addition to inhaled ß2 agonists for patients with any of the following: exacerbations of asthma in the last two years; using inhaled ß2 agonists three times a week or more; symptoms three times a week or more, or waking one night a week.³ An appropriate starting dose of inhaled steroid is 400mcg/day in adults and 200mcg/day in children, the dose should be titrated to the lowest dose that maintains effective symptom control.³ Add-on therapy at Step 3 is initially an inhaled long-acting ß2 agonist (LABA), if the patient responds well this is continued. If there is benefit from the LABA but control is still inadequate, then it should be continued and the dose of inhaled steroid increased to 800mcg/day (adults) and 400mcg/day (children 5-12 years). If there is no response to the LABA, it should be stopped and the inhaled steroid dose increased. Patients with asthma who use LABAs must also use an inhaled steroid and should be monitored closely in the early months of treatment.⁴ Patients who used an inhaled steroid with salmeterol had a lower incidence of asthma-related adverse events compared to those not using inhaled steroids with salmeterol.⁴ Reduced doses of inhaled steroids in combination with LABAs provide safe and effective asthma control.⁵ Other therapies can be tried if control is still inadequate e.g. leukotriene receptor antagonists or sustained release theophylline. Further comparison data is required for leukotriene receptor antagonists against established therapies to determine their place in asthma management: in most adults the additional benefit is less than that associated with add-on therapy with a LABA.⁶At Step 2, children under 5 years could be considered for a low dose inhaled steroid (200-400mcg/day) or a leukotriene receptor antagonist if a steroid is unsuitable.³ Step 3 involves a trial of a leukotriene receptor antagonist or if the child is under 2 years or has persistently poor control, they should be referred to a respiratory paediatrician.

In the small number of patients where asthma is not adequately controlled by the previous steps the following can be considered: increasing inhaled steroid up to 2000mcg/day (adults) or 800mcg/day (children 5-12 years); addition of a fourth drug e.g. leukotriene receptor antagonist, sustained release theophylline or ß2 agonist tablet (Step 4).³ The addition of daily steroid tablets may be required, using the lowest dose to provide adequate control whilst continuing high dose inhaled steroid at 2000mcg/day (adults) (Step 5).³ Once asthma is controlled it is recommended that therapy is stepped down; some patients remain over-treated because this is often not put into practice.³ Reducing the dose by 25-50% should be considered every three months for inhaled steroids.³ Adrenal suppression can be a problem for children taking inhaled corticosteroids and rarely this can lead to adrenal crisis. This has occurred more frequently in children taking fluticasone in higher than licensed doses, perhaps because fluticasone is prescribed above the licensed dose more widely than other inhaled corticosteroids.⁷ Chart 3 shows the variation in prescribing across Strategic Health Authorities for inhaled steroids; higher prescribing occurs in the North.

In children and adults a pressurised MDI is as effective as any other hand held inhaler or nebuliser therapy.³ Inhalers should only be prescribed after patients have received training in the use of the device and have demonstrated satisfactory technique.³ Advice on how to use the treatment can be offered to patients as part of self-management education, reinforced by a personalised action plan.⁸ These plans have been shown to improve health outcomes particularly in those with moderate to severe asthma.³

Chronic obstructive pulmonary disease

COPD is usually diagnosed in patients over the age of 35 who have a risk factor (usually smoking) and who present with one or more of the following; exertional breathlessness, chronic cough, regular sputum production, frequent winter bronchitis and wheeze.⁹ The presence of airflow obstruction should be confirmed by performing spirometry.⁹ Evidence for the value of reversibility testing is limited, it may have a place to determine whether asthma is a contributory cause of the patient's symptoms.¹⁰ NICE guidelines do not recommend reversibility testing routinely as part of the diagnostic process.⁹ Smoking is the main cause of COPD; encouraging patients to stop smoking is one of the single most important factors for managing the disease.

Initial treatment to relieve breathlessness and exercise limitation in COPD is a short-acting ß2 agonist.⁹ Effectiveness of bronchodilators should be assessed by a variety of measures such as improvement of symptoms, speed of symptom relief and exercise capacity in addition to lung function. If symptoms remain then a LABA should be introduced or a combination of a short-acting ß2 agonist with a short-acting anticholinergic can be tried.⁹ Tiotropium has been found to reduce exacerbation rates compared to placebo or ipratropium.¹¹ Small improvements in exacerbation rates and symptoms of COPD have been shown using inhaled steroid and a LABA together, however these must be balanced against the corticosteroid related adverse effects which patients may experience. Although this combination was generally more effective than either drug alone, the differences were not significant for all outcomes.¹¹

Long-term oxygen therapy is indicated in patients with COPD if the partial pressure of oxygen in arterial blood (Pa) is less than 7.3 kPa when stable or if between 7.3 and 8kPa when stable and the patient has at least one of: secondary polycythaemia, nocturnal hypoxaemia, peripheral oedema or pulmonary hypertension. Patients should receive oxygen for 15 hours or more per day to gain the benefit. The new 'home oxygen service' which started on February 1st 2006 allows patients to be referred by their GP to a specialist team to prescribe for their particular needs. Oxygen will be ordered via a Home Oxygen Order Form and submitted to the local oxygen supplier by the specialist team. GP involvement will now be more limited to short burst oxygen therapy pending specialist assessment, and emergency supply.

Prescribing Data

Prescribing of short-acting ß2 agonists has changed little over the last 5 years (4.3 million items and £23.7 million, quarter to September 2005). Salbutamol represents 93% of all prescribing for short-acting ß2 agonists and 89% of cost. Prescribing and spending for single preparation LABAs have decreased by 14% and 12% respectively over the last 5 years to 0.5 million items at a cost of £19.5 million (per quarter). Salmeterol accounts for 90% of both items and cost for LABAs.

Prescribing of antimuscarinic bronchodilators has increased by 43% over the last 5 years to 648,000 items while cost has nearly tripled to £16.5 million (quarter to September 2005). Prescribing of tiotropium accounts for 297,000 items (46% of all antimuscarinic bronchodilators) costing £12.7 million (77% of cost). Prescribing of ipratropium has decreased by 18% to 351,000 items costing £3.8 million, per quarter. Compound bronchodilator prescribing has risen by nearly a quarter to 392,000 items but cost has decreased by 4% to £5.1 million (quarter to September 2005). Almost all of these items are for Combivent .

Prescribing of inhaled corticosteroids as single preparations has decreased by 23% over the last 5 years (2.2 million items, quarter to September 2005) with cost falling by 42% to £36.8 million per quarter. Beclometasone is still most commonly prescribed (1.7 million items, £20.9 million). Prescribing of fluticasone has fallen to 258,000 items while cost has halved to £8.6 million. Prescribing and cost of budesonide have decreased by 45% to 217,000 items and £6.9 million. Compound corticosteroid preparations account for 38% of all inhaled corticosteroid prescribing and two-thirds of cost. Fluticasone with salmeterol accounts for 1 million of these items (77%), and costs £56 million.

Prescribing of aminophylline has decreased by 26% over the last 5 years to 114,000 items costing £400,000 (quarter to September 2005). Theophylline prescribing has fallen by 19% to 132,000 items costing £570,000. Prescribing and spending on leukotriene receptor antagonists have more than doubled over the last 5 years to 182,500 items at a cost of £6.1 million per quarter. Montelukast accounts for over 90% of prescribing and spending on leukotriene receptor antagonists. Cromoglicate and nedocromil are rarely prescribed: 12,000 items between them costing £264,000 (quarter to September 2005).

REFERENCES

1. Asthma UK. Where Do We Stand? December 2004. www.asthma.org.uk
2. Health and Social Care Information Centre. Quality and Outcomes Framework (QOF) for April 2004 - March 2005, England. Data source: QMAS database - 2004/05 data as at end of June 2005 www.ic.nhs.uk/services/qof/documents/QOF0405_SHAs_Prevalence.xls
3. British Thoracic Society, Scottish Intercollegiate Guidelines Network. British Guideline on the Management of Asthma. Thorax 2003; 58: Supplement I. Updated November 2005
4. MHRA. Reminder: Salmeterol (Serevent) and formoterol (Oxis, Foradil) in asthma management. November 2005 Click Here
5. Currie G, Devereux G, Lee D, Ayres J. Recent developments in asthma management. BMJ 2005; 330: 585-589
6. Drug and Therapeutics Bulletin. Leukotriene receptor antagonists - an update. DTB 2005; 43: 85-88
7. CSM/MHRA. Inhaled corticosteroids and adrenal suppression in children. Current Problems in Pharmacovigilance 2002; 28: 7
8. Drug and Therapeutics Bulletin. Action plans in asthma. DTB 2005; 43: 91-94
9. NICE. Management of chronic obstructive pulmonary disease in adults in primary and secondary care. Clinical guideline 12, February 2004 www.nice.org.uk/pdf/CG012_niceguideline.pdf
10. Drug and Therapeutics Bulletin. Beta2 agonist reversibility testing in COPD diagnosis. DTB 2005; 43: 89-91
11. Clinical Evidence freelance writers. Chronic obstructive pulmonary disease. Clinical Evidence 2004; 12: 1-29

• Inhaled steroids should be started at 400 micrograms/day in adults with asthma and the dose titrated to the lowest dose which will maintain effective control (Step 2).
• Patients who need a long-acting ß2 agonist for asthma should also use an inhaled steroid at Step 3.
• Personalised patient action plans have been found to improve health outcomes in some patients with asthma.
• Short-acting ß2 agonists should be used as the initial treatment for COPD patients to relieve breathlessness.
• If patients with COPD continue to experience symptoms either a LABA, an anticholinergic or a steroid could be prescribed: there is no strong evidence to recommend one drug over another.