Asthma cannot be cured; however treatment is aimed at reducing the frequency, severity and length of attacks. Treatment plans would vary from individual to individual since a lot of different factors are involved in asthma. A large number of patients are treated with inhalers, which could be reliever inhalers or preventer inhalers.
1. Reliever inhalers
These are prescribed to help treat symptoms when they occur, that is, during an asthma attack, when peak flow readings are low and before exercise or activity. They help relax and open the airways, making it easier to breath and reducing the risk of an attack. Relievers are medically known as bronchodilators as they widen the bronchi or airways.
Some relievers alleviate symptoms almost instantly (rescue relievers). Others have a longer lasting action (long-lasting relievers). Long-lasting relievers may be prescribed if wheezing, breathing difficulties and coughing persist despite using a preventer and a rescue reliever, or if the sufferer has nocturnal asthma. Common rescue relievers are salbutamol and terbutaline. Another type of reliever is ipratropium bromide, which is often prescribed for babies under two and for older people. Long-lasting relievers include oxitropium, salmeterol, and eformoterol, all of which are inhaled. Side effects are usually mild and pass away quickly. The main ones are a slightly increased heartbeat, and muscle trembling, especially in the hands.
Occasional use of a reliever inhaler may be all that is required where symptoms occur every now and again; however, where a reliever inhaler is required at least 3 times a week to ease symptoms, a preventer inhaler is usually advised.
2. Preventer inhalers
These are prescribed to help prevent asthma symptoms. These are typically used everyday, even when patients do not have symptoms. Preventers are designed to quell swelling and inflammation in the airways and reduce mucus; as such, the sensitivity of the airways is reduced, thereby minimising potential damage. Most preventers are based on corticosteroids, which are steroids but completely different from the anabolic steroids sometimes used by bodybuilders and athletes. The most common types of preventer inhalers include beclomethasone, budesonide, and fluticasone. There are also non-steroid preventers, which are usually used for children; these include sodium cromoglycate and nedocromil sodium. These are usually taken three to four times a day and are not generally as effective as steroids.
It usually takes about 7-14 days for the steroid in a preventer inhaler to build up its effect. As such, it will not give any immediate relief of symptoms. However, after a week or so of treatment, the symptoms will often disappear, or are much reduced. It can take up to six weeks for maximum benefit, after which patients should not need to use a reliever inhaler very often, if at all.
Side-effects of preventer inhalers are unusual at normal doses. These may include hoarseness or loss of voice, oral yeast infections (thrush), and cough. Long-term use may slightly increase the risk of skin thinning, bruising, osteoporosis, eye pressure and cataracts. In children, inhaled corticosteroids may slow growth.
Types of inhaler devices
There are different types of inhaler devices to suit different people. These include,
1. Pressured Metered Dose Inhalers (MDI's), also known as "puffers". They are used to deliver the exact amount of sprayed aerosolised medicine. Medication is mixed into a liquid and forced under pressure into a small aerosol canister. Once activated (usually by pushing down the canister) the liquid evaporates, leaving the active ingredient that is inhaled. A measured dose of the drug is released every time the canister is pushed down. Both relievers and preventers can be given via a puffer.
2. Dry powder inhalers, which contain a small amount of drug in a powder form, contained in a capsule. When activated, the capsule breaks and the powder can be inhaled. Various devices are made by different companies and each has a different method of providing the correct amount of powder for each dose. This type of inhaler device is not usually suitable for children under six. This is because it is usually necessary to breathe fairly hard so as to get the powder into the lungs, children younger than six years cannot often breathe in hard enough to suck in all the powder required.
3. Spacers, which help to coordinate breathing with an inhaler. A spacer is typically a long tube, which clips onto an inhaler, with a mouthpiece on the other end of the tube to breathe in and out of. Spacers allow more medication to enter the lungs than would be possible using an inhaler alone.
4. Nebulisers, in which air or oxygen is forced through the liquid form of a drug, creating a mist, which is inhaled through a mask or mouth piece. They are used to administer high doses of relievers (more than conventional inhalers) in emergency cases and sometimes in children who are too young to use inhalers.
Other medications for the treatment of asthma include, leukotriene modifiers, which reduce the production of, or block the action of leukotrienes (substances released by cells in the lungs during an asthma attack). Leukotrienes cause the lining of the airways to become inflamed, leading to wheezing, shortness of breath and mucus production. Leukotriene modifiers are used alongside other medications to help prevent asthma attack. They are not as effective as inhaled corticosteroids but are ideal for patients who suffer from mild asthma or those who want to avoid corticosteroids.
Theophylline is another form of treatment, which can have anti-inflammatory effects. It is a bronchodilator and may be helpful in relieving symptoms of nocturnal asthma. Due to its low cost, it can be used as an add-on therapy when further asthma control is required. It can however produce some dose-related side effects, including nausea and vomiting, acid reflux, fast or irregular heartbeat, and severe abdominal pain, and as such patients taking theophylline must get regular blood tests to make sure they are getting the correct dosage.
Cromolyn and nedocromil are medications, which can be used daily to help prevent attacks of mild to moderate asthma, as they are rapidly absorbed from the lungs and are impressively safe. They are however not effective for everyone.
Oral and intravenous corticosteroids such as prednisolone and methylprednisolone can be taken to treat acute to severe asthma attacks. These may take a few hours or days to be fully effective. Just like their inhaler counterparts, long-term use of these medications can cause serious adverse effects.