Asthma Medicines

Inhaled Corticosteroids

With greater emphasis being placed on the inflammatory nature of bronchial asthma, the anti-inflammatory agents have achieved greater importance in treatment. The most effective anti-inflammatory agents are corticosteroids, limited to oral or injectable forms until relatively recently, when an inhalation form became available. The topically active inhaled steroids have radically changed and improved the treatment of bronchial asthma. Patients who would have previously been dependent on oral steroids with serious lifetime consequences have been able to be maintained on the spray with virtually no side effects. Those patients with milder forms of asthma but who overuse bronchodilator drugs have been able to decrease their consumption of these agents, reducing the adverse effects of these drugs and perhaps avoiding fatal attacks.

How They Work

Corticosteroids reduce inflammation in the bronchial tubes. Steroids prevent the late phase response and reduce bronchial hyperresponsiveness. The inhaled corticosteroids (bec1omethasone dipropionate, triamcinolone acetonide, flunisolide, budesonide, fluticasone) are “topically active” and achieve their effect on the surface of the bronchial lining. Many of these same agents are used as creams or ointments for skin conditions. If you visualize the lining of the bronchial tube in asthma to be red and inflamed, then the application of the steroid spray is not unlike applying a steroid cream to a skin rash. The results may be a dramatic reduction in inflammation and irritability.

It must be emphasized that for corticosteroids to be effective they must be administered regularly. Tho often patients may abandon a steroid inhaler before it has a chance to work. Compared to the B-adrenergic agonists, corticosteroids do not have an immediate effect and cannot rapidly reduce symptoms. For this reason patients may stop this important medication before it has had an adequate trial. Remember that the primary purpose of corticosteroid sprays is prevention. If used correctly these agents may provide long-term control over asthma. Another major benefit of the regular use of inhaled corticosteroid sprays is the reduced need for B2-agonists, which is extremely important in view of the detrimental effects noted from overusing B2-adrenergic agents.

Specific Agents

The inhaled corticosteroids, their brand names, and the forms that are available. Beclomethasone dipropionate, triamcinolone acetonide, budesonide, fluticasone propionate, and flunisolide are available in the United States. Budesonide (Pulmicort Thrbuhaler) and fluticasone propionate (Flovent Rotadisk) are now available in multidose DPI dispensers. These two agents have only recently been introduced into the United States.

Dosage and Administration

Inhaled corticosteroids may be given in varying dosages depending on individual patients. A common starting dose would be between 100 and 400 micrograms (l1g) per day. High doses (600-2000 ug) may be necessary for control of severe asthma. Inhaled corticosteroids are best given on a twice-a-day basis.

Current information suggests that the inhaled corticosteroids are not equivalent on a per puff or microgram (u.g) basis. Fluticasone propionate appears to be the most potent agent in laboratory studies. Although these laboratory studies appear to correlate with increased effectiveness in patients, direct comparison of the five agents is lacking. The delivery systems used to administer inhaled corticosteroid may affect the effectiveness of the specific medication. For example, when budesonide is administered as a DPI (Thrbuhaler), twice the amount of medication is delivered when compared to the MDI. Budesonide is only available in the DPI form in this country. Fluticasone propionate is available in three dosages (44, 110, and 220 u.g per puff) which allows increased flexibility in adjusting the appropriate dosage for the individual patient.

“High-Dose” Sprays

In view of the large number of sprays needed on a daily basis, “high-dose” sprays have been made available with up to 250 u.g per puff of corticosteroid. These inhalers allow patients with stable asthma to be maintained on as little as two puffs twice a day.

Adverse Effects and How to Prevent Them

The primary side effect of inhaled corticosteroids is development of a yeast infection known as candidiasis in the mouth or throat. With large numbers of puffs from the “low-dose” inhaler or the use of the “high-dose” preparation, there is a greater risk of this infection. This is a local infection and the rare instances of its spreading outside the mouth have typically occurred in patients with lowered immunity who took no precautionary steps. Several preventive steps can be taken to avoid the infection, including rinsing the mouth and spitting after spraying. If unable to rinse the patient may simply drink, flushing residual medication away from the mouth and throat. Passage through the digestive tract leads to rapid breakdown of the drug but rinsing is still preferred. Another extremely helpful step in administering inhaled steroid aimed at reducing the risk of yeast infection is a spacer. This simple device improves delivery of the steroid to the lung as well as reducing the amount likely to be deposited in the mouth and throat. Triamcinolone acetonide (Azmacort) incorporates a spacer in its MDI.

If candidiasis is discovered, treatment should be given promptly, consisting usually of an antifungal agent (nystatin, clotrimazole) prepared as an oral suspension or as a lozenge. It is rare that development of an oral yeast infection will recur and prompt discontinuation of inhaled steroids. In patients with recurrent yeast infection a switch to another anti-inflammatory agent such as cromolyn sodium or nedocromil is indicated.

Another infrequent side effect of inhaled steroids is an effect on the voice. This uncommon effect is usually noted as hoarseness and may be alleviated with a spacer and by a temporary reduction in dosage. Patients who complain of changes in voice should have a careful examination of the vocal cords to ensure that there is no other explanation for the abnormality.

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