Access to asthma drugs a burning issue

By MARTIN JOHNSTON

Ask asthmatics what's in their handbag or pockets and they will probably produce at least two containers of the mix of medicines they must inhale to keep well.

The basic kit includes a blue-coded one for emergencies - Ventolin and Bricanyl are common brands - and a brown one for long-term control, although there are more.

People with moderate to severe symptoms of the disease, which causes wheezing, coughing and breathlessness, have to carry the blue one everywhere.

The prevalence of asthma has exploded in New Zealand and other Western countries. One in six New Zealanders has the disease and its incidence appears to be rising by 50 per cent every 10 to 15 years.

The underlying causes are unknown, but the triggers of attacks are well known and drugs inhaled to relieve and prevent them are highly effective in most patients.

The mainstays are symptom relievers such as Ventolin which relax the muscles in breathing tubes that have tightened, and the preventers, which slowly help to reduce the inflammation of breathing tubes.

The preventers, usually steroid-based, include Flixotide and Pulmicort. Ventolin belongs to a class of drugs called short-acting beta agonists.

In the 1990s, pharmaceutical companies developed long-acting beta agonists (Labas), such as Oxis and Serevent, to give better control of symptoms. Next they mixed them with corticosteroids in combination therapies such as Symbicort and Seretide.

There is also a range of other drugs - including oral steroid tablets or syrups - used to treat an attack that is not clearing with inhaled medicines.

The oral steroids carry a frightening list of potential side-effects, including growth retardation in children, thinning of the bones, easy bruising and cataracts. Doctors try to minimise their use and dosages.

The inhaled drugs can be delivered as a measured squirt from an aerosol-driven puffer, or with a suck by the patient on a breath-activated device.

Some patients take their inhaled drugs through a nebuliser - a device with a bowl, electrical air pump or oxygen, and mask or mouthpiece - but the Asthma and Respiratory Foundation says most mild to moderate attacks can be treated using a reliever drug through a spacer. This is a special plastic tube with a mouthpiece/mask at one end and an attachment for the drug device at the other. It is particularly useful with young children.

Another important device for asthmatics aged over 5 is a peak flow meter. It is a plastic tube with a gauge to measure the speed of air when a patient blows into it. It reveals the state of the asthmatic's breathing tubes and helps decide when to adjust drugs to keep asthma under control.

The Government's drug-subsidising agency, Pharmac, is at odds with drug companies and the foundation over access to some of the newer inhaled medications.

Last year, it made access to long-acting beta agonists easier and did a deal with the AstraZeneca which resulted in one version of its drug Oxis becoming the first-line treatment for adults in this class of drugs.

To receive the drug free (although most will still have to pay a prescription charge and doctors' fee), patients must have poorly controlled asthma and have been using the equivalent of at least 750mcg daily of Pulmicort (400mcg of Flixotide) for at least three months.

The children's thresholds are about half the adult ones. Children have equal access to Oxis and two other Labas, but to get the other drugs subsidised, adults first have to be hypersensitive to Oxis, have suffered a bad side-effect on it, or have it fail to improve their asthma control.

Pharmac set these steroid thresholds last April. Previously they were 1500mcg of Pulmicort or its equivalent.

Up to half of asthmatics in New Zealand are thought to be using steroids at or above the current threshold level for access to a subsidised long-acting beta agonist.

AstraZeneca's business director, Dr Lance Gravatt, says Pharmac's access criteria for these drugs are in line with a number of international medical guidelines, but not with one from the British-based Global Initiative for Asthma.

This says patients should use a long-acting beta agonist if their steroid dose is 400mcg of Pulmicort or equivalent. In New Zealand that would put a Laba into the mouths of 75 to 80 per cent of asthmatics who met Pharmac's other conditions.

"I think there's good support for [Pharmac's steroid threshold] to come down further," Gravatt said.

"On the basis of the clinical trial work, we know that adding a Laba to a mild or moderate dose of preventer will give better asthma control and reduce exacerbations of asthma to a greater degree than increasing the dose of steroid."

Of the combination drugs, only Astra's Symbicort is available in one product and fully subsidised by Pharmac. One of the adults' access conditions is using 1500mcg a day of Pulmicort or its equivalent.

Gravatt says many doctors would consider that dose too high because of the increased risk of side-effects such as those associated with steroid tablets.

But Pharmac's medical director, Dr Peter Moodie, says the adult steroid threshold for a Laba is appropriate, because "a dose of less than 1000mcg is not going to do any harm".

He acknowledges that improving access to medicines leads to better asthma management, but says: "The critical thing was having access to a Laba. Whether we have access to one or two is a pretty small gain."

And he puts little store by the theory that patients comply with their drug regime better if they use one of the combined therapies.

The foundation promotes the use of self-help plans, which are written with a health worker and boil down to a credit-card-sized reminder to patients of how to recognise symptom changes and what to do about them, like adjusting their medicine dosage.

This system, developed in New Zealand and exported, has been shown to make reductions of up to 50 per cent in figures such as asthmatics' hospital admissions, visits to emergency departments and number of nights woken with symptoms.

But the foundation's medical director, Professor Ian Town, says they are used too little. "GPs may not be that experienced with using them and may not be familiar with the research data."

He wants the Health Ministry or district health boards to make use of these plans a measure of the performance of the Primary Health Organisations now being set up.

The foundation has also looked at some of the complementary treatments offered to asthmatics, but advises people to discuss them with their doctor first.

nzherald.co.nz/health